JPH0535099A - Gap adjusting structure for toner concentration detecting sensor - Google Patents

Abstract

PURPOSE:To easily and accurately adjust the gap of a stirring paddle and a toner concentration detecting sensor, on structure for adjusting the gap of the stirring paddle provided inside the developing unit of a laser printer, and the toner concentration detecting sensor. CONSTITUTION:This toner concentration detecting sensor is constituted as follows; a Tc sensor 4 is fixed on an attaching member 5 to expose a detecting surface 4a from an inside surface, and the attaching member 5 is tightened to attach it to the outer periphery of a case 1 with plural adjusting screws 17 via an elastic member 16, to obtain a state where the detecting surface 4a is opposite to the blade 2-1 of the stirring paddle 2 disposed inside the case 1. Then, a developer is supplied into the case 1, the stirring paddle 2 is rotated, and simultaneously, the Tc sensor 4 is operated, to observe the output waveform of the sensor 4. Since the adjusting screw 17 is turned so that the height of the output waveform is a normal value, the gap of the stirring paddle 2 and the Tc sensor 4 can be adjusted.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure for adjusting a gap between a stirring paddle and a toner concentration detecting sensor provided in a developing unit of a laser printer.

Recently, with the increase in speed of various computers, laser printers have been widely used, which can print processing information at high speed and prevent office noise, and manage the print density. Therefore, it is important to monitor / control the concentration of the developer (mixing ratio of toner and carrier) in the developing device.

To this end, a toner concentration detection sensor (hereinafter abbreviated as Tc sensor) is provided at a position corresponding to the developer stirring paddle provided in the developing device. The gap between the Tc sensor and the stirring paddle is provided. As a result, the accuracy of detecting the density of the developer fluctuates, so that there is a need for a new gap adjusting structure for the toner density detecting sensor that can adjust the gap easily and with high accuracy.

[0004]

2. Description of the Related Art A gap adjusting structure of a toner concentration detecting sensor which has been widely used in the past is shown in FIG.
The detection surface 4a is exposed from one surface of the mounting member 5 by inserting and fixing the tip portion 4b of the sensor 4 into the fixing hole 5a of the mounting member 5, and the mounting member 5 is fixed with a plurality of machine screws 7. By tightening on the outer surface of the case 1 through the spacer 6 formed in the plate thickness, the detecting surface 4a of the Tc sensor 4 is disposed inside the case 1 and the developer stirring paddle is rotated in the arrow direction. It is configured so as to face the blade 2-1 formed in 2 with a cap having a constant value.

Therefore, the stirring paddle 2 and the Tc sensor 4
The gap adjustment with the mounting member 5 from the outer surface of the case 1
Is removed and the distance between the outer peripheral surface of the blade 2-1 of the stirring paddle 2 and the outer surface of the case 1 provided inside is measured by, for example, a dip vernier caliper, etc. Is selected, and the spacer 6 is interposed between the outer surface of the case 1 and the mounting member 5 and fastened with a machine screw 7, so that the gap is adjusted to a specified value.

[0006]

The problem with the gap adjusting structure of the conventional toner concentration detecting sensor described above is that it is interposed between the mounting member 5 to which the Tc sensor 4 is fixed and the outer surface of the case 1. Since the spacer 6 is configured to adjust the gap between the stirring paddle 2 and the Tc sensor 4, in the gap adjusting work, the mounting member 5 is removed from the outer surface of the case 1 to stir the outer surface of the case 1. By measuring the distance between the outer peripheral surface of the blade 2-1 of the paddle 2 and selecting the spacer 6 having the thickness of the difference between the measured value and the specified value, and interposing it between the case 1 and the mounting member 5, Because we are adjusting to the gap,
When the gap is adjusted, the attachment member 5 needs to be attached and detached, which causes a problem that the work efficiency of the adjustment is poor.

Further, since the width of the outer peripheral surface of the blade 2-1 of the stirring paddle 2 is small and the stirring paddle 2 is easily rotated, it becomes difficult to accurately measure the distance from the outer surface of the mounting member 5 by a measuring instrument such as a dip vernier caliper. , Therefore Tc by the operator
There is also a problem that a large adjustment difference occurs in the gap between the sensor 4 and the blade 2-1 outer peripheral surface of the stirring paddle 2.

In view of the above problems, it is an object of the present invention to provide a new toner concentration detecting sensor gap adjusting structure capable of easily and accurately adjusting the gap between the stirring paddle and the Tc sensor.

[0009]

According to the present invention, as shown in FIG. 1, a Tc sensor 4 is fixed to a mounting member 5 to expose a detection surface 4a from the inner surface, and the detection surface 4a is provided inside the case 1. The mounting member 5 is fastened to the outer peripheral surface of the case 1 with a plurality of adjusting screws 17 via the elastic member 16 so as to face the blades 2-1 of the stirring paddle 2 and the developer is placed inside the case 1. Is supplied to rotate the stirring paddle 2 and operate the Tc sensor 4 to observe the output waveform, and the adjusting screw 17 is rotated so that the height of the output waveform becomes a specified value. The gap between the stirring paddle 2 and the Tc sensor 4 can be adjusted.

[0010]

In the present invention, when the developer is supplied into the case 1 and the stirring paddle 2 is rotated and the Tc sensor 4 is operated and the output thereof is observed with an oscilloscope, as shown in FIG. The output waveform of the sensor 4, that is, the waveform generated each time the blade 2-1 of the stirring paddle 2 approaches the detection surface 4a of the Tc sensor 4, is displayed.

The height h of the waveform correlates with the gap between the stirring paddle 2 and the Tc sensor 4 as shown in FIG. 3 (b), and each adjusting screw 17 is rotated from the outside of the case 1 shown in FIG. Then, the mounting member 5 is moved to adjust the height h of the output waveform to the height of the specified gap A point so that the gap can be set to a specified value. Therefore, the gap adjustment between the toner concentration detection sensor and the stirring paddle 2 can be performed. It can be performed easily and with high accuracy.

[0012]

Embodiments of the present invention will be described in detail below with reference to FIGS. FIG. 1 is an enlarged sectional view showing a gap adjusting structure of a toner concentration detecting sensor according to the present embodiment, FIG. 2 is an enlarged sectional view showing a gap adjusting structure of another embodiment, and FIG. 3 is a toner concentration detecting for explaining the operation. The output waveform diagram of the sensor is shown. In the figure, the same members as those in FIG. 3 are denoted by the same symbols, but the other 16 are leaf springs for urging the Tc sensor toward the outer surface of the case, and 17 is the Tc sensor. It is an adjusting screw for adjusting the gap of.

As shown in FIG. 1, the leaf spring 16 is a ring-shaped member formed of a metal having excellent elasticity, for example, a phosphor bronze thin plate, having an inner and outer diameter dimension which can be interposed between the outer surface of the case 1 and the flange portion of the mounting member 5. The plate is formed in a wave shape with a constant height.

The adjusting screw 17 is a general-purpose machine screw having a size capable of being screwed into the female screw hole of the case 1 for fastening the mounting member 5 of the Tc sensor 4. In the gap adjusting structure of the toner concentration detecting sensor using the above member, as shown in FIG. 1, the tip 4b of the Tc sensor 4 is inserted into and fixed to the fixing hole 5a of the mounting member 5 as in the prior art so as to fix the detection surface. 4a is exposed, and the detection surface 4a is made to face the blade 2-1 of the stirring paddle 2 arranged inside the case 1 and the leaf spring 16
The mounting member 5 is fastened to the outer peripheral surface of the case 1 with a plurality of adjusting screws 17 via the, and the mounting members 5 are moved in the direction of the stirring paddle 2 by rotating each of the adjusting screws 17. I am configuring.

The gap adjusting method between the stirring paddle 2 and the Tc sensor 4 having the above-mentioned structure is supplied by supplying the developer into the case 1 and rotating the stirring paddle 2 and the Mg roller 3 in the arrow direction. The developer is stirred by the blade 2-1 of the stirring paddle 2 and the Tc sensor 4 is operated to observe the output waveform as shown in FIG. 3 (a) with an oscilloscope.

Then, the height h of the output waveform is varied by rotating each adjusting screw 17 to move the mounting member 5 toward the stirring paddle 2, and the value is at point A in FIG. 3 (b). The adjustment screw 17 is stopped from rotating at a height of a gap having a specified value, for example, 0.3 mm, and fixed by a locking agent or the like.

As a result, the adjusting screw provided outside the developing device
By rotating 17 the stirring paddle 2 and Tc sensor 4
Since the gap between and becomes a specified value, the gap can be adjusted easily and highly accurately.

The gap adjusting structure of another embodiment is
As shown in FIG. 2, a mounting member 25 having a male screw 25b provided on the outer circumference of the small diameter portion of the flanged cylindrical base and the Tc sensor 4 fixed to the central fixing hole 25a is provided at a position corresponding to the stirring paddle 2 of the case 21. It is screwed into the female screw hole through the leaf spring 16 and the mounting member 25 is rotated to a specified value while observing the output waveform of the Tc sensor 4 as in the above embodiment, and is shown in the drawing. The same effect as above can be obtained by locking the rotation with a lock screw not provided.

The above description is based on the illustrated embodiments, but the present invention is not limited to the embodiments described above,
For example, a packing formed of synthetic rubber or an elastic body such as a plurality of coil springs may be interposed between the mounting member and the case, and it is not limited to the leaf spring.

[0020]

As is apparent from the above description, according to the present invention, there is an advantage that the gap between the stirring paddle and the Tc sensor can be adjusted easily and highly accurately with a very simple structure, which is extremely economical and It is possible to provide a gap adjusting structure of a toner concentration detecting sensor which can be expected to improve reliability.

[Brief description of drawings]

FIG. 1 is an enlarged sectional view showing a gap adjusting structure of a toner concentration detecting sensor according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view showing a gap adjusting structure of another embodiment.

FIG. 3 is a diagram showing an output of a toner concentration detection sensor for explaining an operation.

FIG. 4 is a sectional view showing a gap adjusting structure of a conventional toner concentration detecting sensor.

[Explanation of symbols]

1, 21 is a case, 2 is a stirring paddle, 2-1 is a blade, 3 is a Mg roller, 4 is a Tc sensor, 4a is a detection surface, 4b is a tip portion, 5 and 25 are mounting members, and 5a and 25a are fixing holes. , 16 is a leaf spring, 17 is an adjusting screw, 25b is a male screw

Continued front page    (72) Inventor Etsuo Aoyama             1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture             Within Fujitsu Limited (72) Inventor Keiichiro Sakata             1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture             Within Fujitsu Limited

Claims (3)

[Claims] 1. A toner concentration detection sensor (4) is fixed to a mounting member (5) to expose the detection surface (4a) from the inner surface, and the detection surface (4a) is disposed inside the case (1). The mounting member (5) is arranged on the outer peripheral surface of the case (1) through the elastic member (16) so as to face the blade (2-1) of the stirring paddle (2) and the mounting member. The moving means (17) of (5) is provided, the developer is supplied to the inside of the case (1) to rotate the stirring paddle (2), and the detection sensor (4) is operated to output the output waveform. Observe and move
A gap adjusting structure of a toner concentration detecting sensor, wherein the height of the output waveform can be adjusted to a height of a specified gap value by rotating (17). 2. The attachment means (5), wherein the moving means is arranged on the outer peripheral surface of the case (1) through the elastic member (16).
Provided on the adjusting screw (17), and by rotating the adjusting screw (17), the detection surface (4a) exposed from the mounting member (5)
2. The gap adjusting structure for a toner concentration detecting sensor according to claim 1, wherein said structure is arranged so as to be close to said stirring paddle (2). 3. The moving means comprises a male screw (25
The toner concentration detection sensor (4) is fixed to the mounting member (25) in which b) is screwed, and the mounting member (25) is perforated on the outer peripheral surface of the case (21) via the elastic member (16). 2. The structure is such that the gap between the detection surface (4a) and the stirring paddle (2) is adjusted by screwing into the screwed hole.
Gap adjustment structure of the toner concentration detection sensor described.