JPH02227685A - Magnetic field distribution measuring instrument - Google Patents

Abstract

PURPOSE:To take an accurate measurement by detecting the position of a pattern, formed corresponding to a measuring element on a base, with the irradiating light of an exposure source which synchronizes with the movement of a photosensitive body. CONSTITUTION:An electrophotographic device irradiates the endless photosensitive body 1 with the light corresponding to information from the exposure means 3 and develops a formed electrostatic latent image into a toner image by a magnetic brush developing device 4. The photosensitive body 1 fitted with measuring elements 13 and 14 for measuring the intensity of a magnetic field in the vertical and horizontal directions is replaced with the base 12 almost in the same shape and a magnetic field distribution on the base 12 is measured. At this time, a pattern indicating the positions of the elements 13 and 14 on the base 12 is formed on the base 12 and the light of the means 3 is detected by a detecting means 16 through the pattern, so that the measurement start position of the magnetic field distribution on the base 12 is set according to the detection signal.

Description

[Detailed Description of the Invention] [Summary] An electrophotographic apparatus having an endless photoconductor, an exposure source that irradiates light according to information onto the photoconductor, and a magnetic brush developer is provided with horizontal and vertical directions. A device for measuring the magnetic field distribution of a magnetic brush developer, in which a support having the same shape as the photoreceptor and having a measuring element for measuring the strength of the magnetic field is attached instead of the photoreceptor, enables accurate measurement. For the purpose of The measurement start position of the magnetic field distribution on the support is configured to be set based on the detection signal of the means.

[Industrial application field]

The present invention provides an electrophotographic apparatus that includes an endless photoreceptor, an exposure source that irradiates light according to information onto the photoreceptor, and a magnetic brush developer, with magnetic field strengths in the horizontal and vertical directions. The present invention relates to an apparatus for measuring the magnetic field distribution of a magnetic brush developing device by attaching a support having the same shape as the photoreceptor and having a measuring element thereon attached thereto instead of the photoreceptor.

In an electrophotographic apparatus, a developer is used to develop an electrostatic latent image formed on a photoreceptor. This developer forms a magnetic brush with a magnetic roller in the developer,
It is brought into contact with the electrostatic latent image on the photoreceptor to form a toner image. Therefore, in order to obtain clear print density, it is important to fully understand the characteristics of the developer. However, conventional measurements of developer characteristics are based on static characteristics, and because the behavior of the developer during actual development cannot be determined, it is necessary to measure the characteristics of the developer during operation.

FIG. 9 is a schematic diagram of the electrophotographic apparatus.

In FIG. 9, first, a photoreceptor 1, which is a recording medium, is uniformly charged using a charger 2 and exposed to a predetermined image by an exposure means 3 such as a zero-order laser beam scanning chemical system or an LED optical system. to form an electrostatic latent image on the photoreceptor l. The electrostatic latent image on the photoreceptor 1 is converted into a toner image by a magnetic brush developer 4 filled with a developer 5. The toner image on the photoreceptor 1 is
The image is transferred onto recording paper 7 by transfer device 6 . Further, the image transferred onto the recording paper 7 is fixed to the recording paper 7 by a fixing device (not shown). The magnetic brush developing device 4 includes a magnet roller in which a plurality of magnetic poles are provided in the circumferential direction, and a sleeve made of a non-magnetic material provided to cover the outer periphery of the magnet roller.

On the other hand, the photoreceptor 1 is neutralized by a static eliminator 8, and the developer remaining on the photoreceptor 1 after the transfer is removed from the photoreceptor 1 by a cleaner 9.

As described above, in an electrophotographic apparatus using a cylindrical photoreceptor l and a magnetic brush developing device 4, the developer 5 used in the magnetic brush developing device 4 is a one-component developer using magnetic toner and an iron powder developer. There are two-component developers that are a mixture of magnetic carrier and toner.

[Conventional technology]

The characteristics of the developer have a great influence on print quality, so
It is important to fully understand the characteristics of the developer 5 used in the magnetic brush developer 4.

Conventionally, these properties have been determined by measuring electrical resistance, charge amount, magnetic properties, shape, particle size, and the like.

[Problem to be solved by the invention]

However, since the characteristics determined in this way are static characteristics and not dynamic characteristics, the behavior of the developer during actual development was not known.

Here, the magnetic brush developing device includes a magnetic roller 10 for making a magnetic brush and a developing sleeve 1 for conveying the developer 5.
1 and a developer 5 containing magnetic powder around it, it is a kind of magnetic circuit, and the overall dynamic characteristics of the developer 4 including the developer 5 can be determined from the magnetic field distribution around the developer 4 during development. I found out that it is required.

Therefore, an object of the present invention is to provide a magnetic field distribution measuring device that can accurately measure magnetic field distribution.

[Means to solve the problem]

As shown in FIG. 1, an object of the present invention is to provide an electrophotographic photographic system having an endless photoconductor 2, an exposure source 3 for irradiating light according to information onto the photoconductor 2, and a magnetic brush developing device 5. A support 12 having the same shape as the photoreceptor 2, on which a measurement element 13 for measuring the strength of the magnetic field in the horizontal direction and a measurement element 14 for measuring the strength of the magnetic field in the vertical direction are attached to the apparatus, is attached to the photoreceptor 2. A device for measuring the magnetic field distribution on the support 12, which forms a pattern 17 on the support 12 indicating the positions of the measuring elements 13 and 14 on the support 12. , a developing magnetic field distribution in which a detection means 16 is provided for detecting the light from the exposure source 3 through the pattern 17, and a detection signal from the detection means 16 is used to set a measurement start position of the magnetic field distribution on the support 12. Achieved by measuring equipment.

[Function] As mentioned above, the measurement element 1 provided on the support 12
A pattern 17 is formed corresponding to the position of 3.14, and the position of this pattern 17 is
Since the detection is performed using the light from the exposure source 3 that is accurately irradiated in synchronization with the movement of the magnetic field, it is possible to accurately measure the magnetic field distribution.

〔Example〕

Embodiments of the magnetic field distribution measuring device according to the present invention will be described below with reference to the drawings.

(a) Explanation of the principle of measuring magnetic field distribution First, the principle of measuring the magnetic field distribution on the photoreceptor l will be explained using FIGS. 1 and 2.

As shown in FIG. 1, a cylindrical support 12 having the same shape and the same material as the cylindrical support for the photoreceptor 1 is used, and on its surface,
Hall elements 13 and 14 are attached to measure the magnetic field distribution in two directions, circumferential and perpendicular to the cylindrical support 12.

At this time, if the magnetic sensor (Hall element 13, 14) 21 is set at position A as shown in FIG. and BK in the circumferential direction.

B=BV +B,・−・−・・・−・−(1) Here,
Letting the magnitude of each vector be BV and BH, the magnitude B and direction δ of the composite magnetic field are B=Ii1=几;-jMie i-1... (2) δ= jan
-' B H/ B v ------ (31 has B
It turns out that it is sufficient to measure VSBN.

These BV and B processes include a Hall element 13 in the moving direction of the support 12 in FIG. 1, and a Hall element 1 in a direction perpendicular to the moving direction.
4.

Therefore, by individually introducing various developers into the magnetic brush developing device 4 and measuring and comparing the magnetic field distribution,
Differences in dynamic properties (fluidity, magnetic properties) of developers can be determined.

(b) Explanation of the overall configuration of the measuring device FIG. 3 is a diagram illustrating the overall configuration of the magnetic field distribution measuring device.

In the figure, reference numeral 12 denotes a cylindrical support, which has the same shape (cylindrical shape) as the photoreceptor l in FIG. 9 and is made of a non-magnetic material. What is attached is a motor 15 for rotationally driving the cylindrical support 12;
6 is a rotary encoder, which is installed coaxially with the cylindrical support 12 and is for detecting the rotation angle position of the cylindrical support 12 that is rotationally driven by the motor 15; 17 is a rotation control device; , which controls the rotational driving and stopping of the motor 15, and 18 is an encoder control device which converts the output signal from the rotary encoder 16 into a pulse signal and outputs the count output as a position signal (angle data). , 19 is a sensor control device, which receives the output signal from the Hall element 13.14, converts it into digital data and outputs it, 20 is a central control device, which controls each control device 17, 18, 19. It is something.

In the configuration described above, the operation will be explained.

It is assumed that the support 12 is attached in place of the photosensitive drum 1 of the electrophotographic recording apparatus shown in FIG.

Further, at the time when the support body 12 is attached to the apparatus, it is not known where the Hall elements 13 and 14 are located with respect to the developing device 4. Therefore, when the operator selects the Hall element 13.
After the position 14 is visually aligned to, for example, the position of the wire line 2a of the front charger 2, the rotation angle θ is read by the sensor control device 19 using this position as a reference.

First, the central control device 20 issues a drive command to the rotation control device 17 to drive the motor 15 and rotate the support body 12 while controlling the rotation speed by the rotation control device 17. At this time, the central controller 20 reads data on the rotation angle θ based on the output of the rotary encoder 16 via the encoder controller 18, and determines the position of the Hall elements 13 and 14 with respect to the developer 4. know. At the same time, the central control device 20 receives data in BylB as a result of the sensor control device 19 measuring the output of the magnetic sensor (Hall element 13, 14) 21, and this Bll, 8M
The magnetic field distribution (B, δ) is determined by processing the data based on the integration formula described above.

(C) Description of one embodiment By the way, in the device configuration shown in FIG. 3, the positioning of the Hall elements 13 and 14 is performed visually, but this positioning method has poor position reproducibility; A deviation occurs in the measurement start position for each different developer, making it impossible to perform accurate measurement.

Therefore, in the present invention, the exposure source 3 provided within the electrophotographic recording apparatus is effectively utilized to enable accurate positioning.

FIG. 1 is an explanatory diagram of an embodiment of the present invention, and FIG. 4 is an explanatory diagram of a cylindrical support according to an embodiment. Made of
A slit 47 having a slit width of 100 .mu.m is provided at one end thereof at the same position on the circumference of the Hall elements 13 and 14. A light receiving sensor 46 such as a phototransistor is installed inside the slit 47 as shown in FIG.

Furthermore, this light receiving sensor 46 detects a laser beam which is an exposure source, and its output is inputted to an angle counting section 49 provided in the encoder control device 1B shown in FIG. In this angle counting section 49, a rotary encoder 1 is provided.
A circuit for amplifying and shaping the waveform signal from 6 and a counter for counting the output pulses of this circuit are provided.

Therefore, after the output of the light receiving sensor 46 is amplified and shaped by a circuit (not shown), the value of the counter can be reset by inputting the output to the clear terminal of the counter (not shown) of the angle counting section 49.

Note that the output of the light receiving sensor 46 is also input to the central control device 20, and the central control device 20 starts a measurement operation based on this output signal. Here, the laser source is centrally controlled by the controller of the electrophotographic recording device.
The device 20 is driven and controlled by applying a write signal.

In this way, in this embodiment, a laser beam that is scanned with high precision inside the electrophotographic apparatus is used, and the measurement start position is set using this as a reference, so that an accuracy of ±0.1@ or less is obtained. be able to.

Note that although this embodiment has been described as an example using a laser beam, the present invention is not limited to this.

(d) Description of other embodiments In the above-mentioned embodiment, since the rotary encoder 16 was used as the position reading means, there was a problem that the measuring device was large and complicated.

In this embodiment, by using an exposure laser beam within the electrophotographic apparatus as the position reading means, the apparatus can be made smaller and simpler.

FIG. 5 is an explanatory diagram of another embodiment.

As shown in FIG. 5(a), patterns 45 are provided at intervals of 1 on the circumference of a cylindrical support 12 having the same shape as the photoreceptor l.
The cylindrical support 12 is made of an aluminum tube with a diameter of 80-1 and a length of 260s11. Furthermore, the pattern 45 was formed by providing a groove that would not be reflected when the exposure laser beam 48 was irradiated.

Then, as shown in FIG. 5, the polygon mirror is fixed so that the exposure laser beam 48 is placed on the pattern 45 provided on the cylindrical support 12, and the exposure laser beam 48 is irradiated. The reflected light is detected by an optical sensor 67 using a phototransistor. When the exposure laser beam 48 is irradiated onto the pattern 45, there is no reflection, so no output is produced, but when the exposure laser beam 48 is irradiated onto a region other than the pattern 45, the optical sensor 67 detects the reflected light and generates an output. do. The output signal of this optical sensor 67 is counted by the counter in the angle counter 49 in the same manner as described above, and the rotation angle of the cylindrical support 12 is measured.

At this time, the position of the Hall elements 13 and 14 is detected using the method of the above-mentioned embodiment.

(+1) Description of another embodiment In the other embodiments described above, it is necessary to adjust the position of the polygon mirror so that the laser beam from the laser source is irradiated onto the pattern, which requires time to set.

Therefore, in this embodiment, measurement can be performed while scanning the laser beam 48. However, laser beam 18
When the pattern 45 is irradiated with light, there is no reflection, so no output is produced. However, when the light is irradiated onto a region other than the pattern 45, the reflected light is detected and an output is generated. At this time, since the output of the optical sensor 67 scans the exposure laser beam 48, it becomes a pulse-like signal as shown in FIG. 7(a). In this case, it is not possible to detect the pattern 45 and count the angle by the angle counting section 49.
As shown in FIG. 6, a single-shot multivibrator 69 was inserted between the angle counting section 49 and the optical sensor 67 to remove the pulse signal generated by the scanning of the exposure laser beam 48.

FIG. 8 is a time chart showing the relationship between the input and output of the single-shot multivibrator 69 used in this example, and a retriggerable single-shot multivibrator was used. When a pulse is input to this single-shot multivibrator 69, a pulse with a width t1 is output as shown in Fig. 8. If the input is again during tw, an output of tw is further output from there. . So, t.

By making the scan period ts of the exposure laser beam 48 longer than the scanning period ts (FIG. 8(a)), a pulsed input signal can be converted into a constant output as shown in FIG. 2(b). .

As is clear from the above description, the rotation angle of the cylindrical support 12 can be measured using the angle needle number section 49, as in the case of the previous embodiment.

In this way, in this embodiment, it is possible to eliminate the need for a rotary encoder, making it possible to downsize and simplify the measuring device, and to reduce the cost.

【Effect of the invention〕

As described above, according to the present invention, an electrophotographic apparatus including an endless photoreceptor, an exposure source that irradiates light according to information onto the photoreceptor, and a magnetic brush developer can be used in a horizontal direction. A support having substantially the same shape as the photoreceptor is attached in place of the photoreceptor, to which a measurement element for measuring the strength of the magnetic field and a measurement element for measuring the strength of the magnetic field in the vertical direction are attached, In a measurement device that measures a magnetic field distribution on the support, a detection device that detects light from the exposure source through a pattern on the support that indicates the position of a measurement element on the support. By providing a means to measure the magnetic field distribution on the support body using the detection signal, it is possible to dramatically improve the reproducibility of the magnetic field distribution measurement, allowing accurate measurement of the magnetic field distribution. becomes possible.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of one embodiment, Fig. 2 is an explanatory diagram of the magnetic field distribution measurement principle, Fig. 3 is an explanatory diagram of the overall configuration of the measuring device, and Fig. 4 is an explanatory diagram of the cylindrical support according to one embodiment. 5 is an explanatory diagram of another embodiment; FIG. 6 is an explanatory diagram of another embodiment; FIG. 7 is a time chart showing the relationship between the optical sensor output and the single shot multivibrator output; Figure 8 is a time chart showing the operation of the single shot multivibrator, and Figure 9 is a schematic diagram of the electrophotographic recording device. In the figure, l is a photoreceptor, 2 is a developer, IO is a magnetic roller, 11 is a developing sleeve, 12 is a cylindrical support, 13 and 14 are Hall elements, 46 is a light receiving sensor, 47 is a slit, and 48 is a laser beam , 49 indicates an angle counting section. - Great offer! iaq diagram $I interstitial I determination device. All #O Ir holes 13L light supply 3I21, mW-3f 1ift >l'lLR, buried tn tf
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Claims (1)

[Claims] An endless photoreceptor (2), an exposure source (3) that irradiates light according to information onto the photoreceptor, and a magnetic brush developer (5).
the photoreceptor (2), in which a measuring element (13) for measuring the strength of a magnetic field in the horizontal direction and a measuring element (14) for measuring the strength of the magnetic field in the vertical direction are attached to an electrophotographic apparatus having the above;
In an apparatus for measuring the magnetic field distribution on the support (12), a support (12) having approximately the same shape as the photoreceptor (2) is attached in place of the photoreceptor (2). Body (1
2) a detection means (16) forming a pattern (17) indicating the position of the measurement element (13, 14) on the top and detecting light from the exposure source (13) via the pattern (17);
), and the measurement start position of the magnetic field distribution on the support body (12) is set based on the detection signal thereof.