JP2002071303A - Thickness-detecting sensor and device and image-forming device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make thickness-detecting device highly accurate and reduce its cost, without having to use using the conventional supporting member for utilizing the principle of lever. SOLUTION: By constituting the thickness-detecting device, in such a way that a paper sheet is passed through the pressed part between a magnetic body roller 201 and a wheel-shaped magnetic body roller 202 which is arranged opposite to and in contact with the magnetic body roller 201 and in which a coil is wound on an axles part, the inductance of a magnetic path is changed, according to the thickness of the paper leaf body.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thickness sensor for detecting the thickness of a paper sheet, a thickness detecting device, and an image forming apparatus using the same, which is used in an image forming apparatus such as a copying machine and an LBP. .

[0002]

2. Description of the Related Art FIG. 5 shows an example of a conventional thickness sensor. Two rollers 303 and 302 opposed to each other so as to be in pressure contact with each other, a support member 303 having one side fixed to the roller and a magnetic body fixed to the other side, and a magnetic body 305 attached to the support member. A transformer 306 near the body 305 and forming a magnetic path with the magnetic body 305;
And a spring mechanism 304 for urging the support member 303.

When a paper sheet enters between the rollers, the paper sheet 1
The lower roller 302 is lowered by the thickness of 23, the support member 303 rotates clockwise about the rotation axis, and the magnetic body 305 attached to the support member 303 moves upward. The support member 303 is urged by a spring mechanism 304 in a counterclockwise direction on the paper surface, and is urged in a direction in which the roller pair comes into pressure contact with each other. Magnetic body 3 attached to support member 303
05 is in contact with the transformer 306, and the inductance value of the transformer 306 changes by the amount of movement of the magnetic body 305. Using this inductance value, the paper sheet 12
3 is detected.

[0004]

However, in the above-mentioned conventional example, a mechanism such as a support member utilizing the principle of leverage for moving the magnetic material in accordance with the amount of movement of the lower roller is required, thus increasing the cost.

In addition, there is a drawback that the detection accuracy is low because a mechanism such as a support member is required.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems. By providing the function of a transformer and a magnetic material to a roller pair, the distance between the roller pair according to the thickness of the paper sheet can be reduced. It is an object of the present invention to provide a thickness sensor, a thickness detecting device, and an image forming apparatus using the thickness detecting device, which can reduce cost and achieve high accuracy by eliminating a mechanism for transmitting the magnetic material. .

[0007]

In order to achieve the above object, a first aspect of the present invention is a wheel-shaped magnetic roller in which a coil is wound around a magnetic roller and an axle portion opposed to and disposed in contact with the magnetic roller. It is characterized by having a body roller. In this configuration, the transformer and the roller can be integrated, and the magnetic body and the roller can be integrated.

The invention according to a second aspect is characterized in that it comprises a magnetized magnet roller, and a wheel-shaped magnetic roller in which a coil is wound around an axle portion which is disposed so as to be in contact with the magnet roller. In this configuration, the transformer and the roller can be integrated, and the magnetic body and the roller can be integrated.

A third aspect of the present invention is characterized in that a means for pressing the magnetic roller against the wheel-shaped magnetic roller is provided. In this configuration, the magnetic roller and the wheel-shaped magnetic roller can be pressed against each other.

According to the fourth aspect of the present invention, a magnetic path is formed between the magnetic roller and the wheel-shaped magnetic roller, and the sheet is passed through the pressure contact portion between the magnetic roller and the wheel-shaped magnetic roller. Thus, the inductance of the thickness detection sensor is changed according to the thickness of the paper sheet. With this configuration, the inductance of the thickness detection sensor can be changed according to the thickness of the sheet. In the invention of claim 5,
A thickness detection sensor and an oscillator utilizing the inductance of the thickness detection sensor are provided, and the oscillation frequency of the oscillator is changed according to the thickness of the paper sheet. With this configuration, the oscillation frequency of the oscillator can be changed according to the thickness of the sheet. A sixth aspect of the present invention is characterized in that a thickness detecting device is provided. With this configuration, the image forming apparatus can detect the thickness of the sheet.

According to the seventh aspect of the present invention, a magnetic path is formed between the magnetic roller and the wheel-shaped magnetic roller, and the sheet is passed through the pressure contact portion between the magnetic roller and the wheel-shaped magnetic roller. Thus, the inductance of the thickness detection sensor is changed according to the thickness of the paper sheet. With this configuration, the inductance of the thickness detection sensor can be changed according to the thickness of the sheet. In the invention of claim 8,
A thickness detection sensor according to claim 7 and an oscillator using the inductance of the thickness detection sensor are provided, and the oscillation frequency of the oscillator is changed according to the thickness of the paper sheet.
With this configuration, the oscillation frequency of the oscillator can be changed according to the thickness of the sheet.

According to a ninth aspect of the present invention, there is provided the thickness detecting device of the eighth aspect. With this configuration, the image forming apparatus can detect the thickness of the sheet.

[0013]

(Embodiment 1) Here, a thickness detecting device provided in an image forming apparatus will be described.

FIG. 1 is a sectional view showing an example of this type of image forming apparatus, for example, a laser beam printer.

In FIG. 1, reference numeral 100 denotes a controller unit, which converts an electric signal, which is code data input from a host computer (not shown), into a video controller unit 103.
Then, after being developed into a dot image and stored in the memory inside the video controller, it is returned to the engine unit 102 as a video signal. Each element of the engine unit 102 is controlled by the engine controller 105, and exchange of video signals with the controller unit 100 is also performed via the engine controller 105. Engine controller 10
The video signal input to the video interface unit (not shown) of No. 5 is sent to the laser driver 106, where ON / OFF of the semiconductor laser 107 is controlled.
Laser light 110 emitted from this semiconductor laser 107
Is deflected by the polygon mirror 108 and the photosensitive drum 1
The scanning light in the longitudinal direction 12 is projected on the photosensitive drum 112 via the mirror 109. Photosensitive drum 112
Rotates in the direction of the arrow and is temporarily charged by the primary charger 111, and then is exposed to light in accordance with ON / OFF of the laser beam to form an electrostatic latent image on the surface of the photosensitive drum. And
Colored charged particles (hereinafter, referred to as toner) are applied by the developing device 113 to obtain a visible image. The paper sheet 123 is taken out of the paper supply cassette 120 by the paper supply roller 121 and is conveyed by the conveyance rollers 134a and 134b. Paper leaf 12
3 reaches the photosensitive drum through the thickness detecting device. When the sheet body 123 reaches between the photosensitive drum and the transfer roller, the visible image is transferred. Transfer residual toner is transferred to the photosensitive drum 1
The surface of the photosensitive drum 112 is wiped off by the cleaning device 115, and the photosensitive drum 112 is ready for the next image forming step.

On the other hand, the paper sheet on which the unfixed toner image is placed is
After passing through the fixing device 116 to obtain a permanent fixed image, the paper sheet is discharged out of the apparatus as a final print in the direction of the arrow in the figure. It should be noted that the arrow in FIG.
4 shows a feeding trajectory of a sheet taken out of the printer and conveyed.
The fixing device 116 has a heater (fixing heater) 119 in the hollow fixing roller 117. When the heater 119 is energized, the fixing roller 117 is overheated, and a sensor (not shown) for detecting the surface temperature of the fixing roller 117 is provided. The output is input to a temperature controller (not shown), and the heater 119
Are turned ON / OFF to maintain a predetermined surface temperature.
The pressure roller 118 is pressed against the fixing roller 117 by an urging means (not shown), and the unfixed toner on the sheet is heated together with the sheet in a nip formed by the fixing roller 117 and the pressure roller 118. , And is permanently fixed. Then, the paper sheet 123 is discharged in the direction of LS.

In the above process, information on the thickness of the paper sheet detected by the thickness detecting device is sent to the engine controller 105, and the engine controller uses this information to control the image formation of the primary charger, the developing device, the transfer roller and the like. Change conditions. Further, the engine controller 105 also changes the temperature of the fixing roller.

Thus, the image forming apparatus can print an optimum image even when the thickness of the paper sheet changes.

FIG. 2 is a schematic view of a thickness sensor according to the present invention. Magnetic roller 20 made of magnetic material such as ferrite
1. a wheel roller 202 made of a magnetic material such as ferrite having a wheel-like shape disposed to face the magnetic material roller;
A bobbin 20 that supports a wheel roller and winds a coil
3. The basic configuration includes a bearing 204 for receiving the magnetic roller 201, a spring 205 for urging the magnetic roller 201 against a wheel roller, a support member 207 for supporting the magnetic roller, and a coil 210.

The support member 207 is attached to the image forming apparatus main body. The magnetic roller 201 is urged against the wheel roller 202 by a spring 205, and when there is no sheet 123, the magnetic roller 201 and the wheel roller 202 are in contact. The wheel roller 202 forms a magnetic path with the magnetic roller 201. When the sheet 123 enters between the rollers, the magnetic roller 201 is displaced upward according to the thickness of the sheet, and the magnetic roller 201 is slightly separated from the wheel roller 202. By separating the two rollers by the thickness of the paper sheet, an air gap is generated in the magnetic path formed by the two rollers, and the inductance value of the coil decreases. The inductance value generated in the coil is inversely proportional to the amount of displacement of the magnetic roller 201.

As described above, the thickness of the sheet body 123 is directly
Since it is reflected on the air gap of the magnetic path, that is, on the inductance value of the coil, the paper sheet
3 can be detected.

Further, since one roller and the magnetic body are integrated and the other roller and the transformer are integrated, the number of parts can be reduced, and the cost can be reduced.

FIG. 3 is a control block diagram of an image forming apparatus provided with a thickness detecting device. The thickness sensor whose inductance value changes according to the thickness of the paper sheet 123 is connected to the LC oscillation circuit 208. The LC oscillation circuit 208 oscillates at a frequency corresponding to the inductance value of the thickness sensor. That is, oscillation is performed at a frequency corresponding to the thickness of the paper sheet 123. The signal of the oscillation circuit 208 is frequency-divided by the frequency divider 209 and sent to the engine controller 105. The engine controller 105 detects this frequency and detects
The thickness of the fixing roller is recognized, and control of image formation such as a primary electric withstand device, a developing device, and a transfer roller (not shown) and a temperature of the fixing roller are changed.

As a result, it is possible to print an image optimal for the thickness of the paper sheet 123.

Here, the LC oscillation circuit has been described using the LC Colpitts oscillation circuit, but is not limited to this.

Although the description has been made by inserting the frequency divider between the oscillation circuit and the engine controller, it is not always necessary to insert the frequency divider.

By practicing the present invention as described above, it is possible to improve the accuracy and cost of the thickness detecting device. Further, it is possible to provide an image forming apparatus capable of printing an optimum image according to the thickness of the paper sheet.

(Embodiment 2) In the first embodiment, the magnetic roller 201 is used. In the second embodiment, a magnetized magnet roller 206 is used.

FIG. 4 is a schematic view of a thickness sensor according to the second embodiment.

The description of the same numbers as in the first embodiment is omitted.

The difference from the first embodiment is a magnet roller 206 made of a magnet and a support member 208 for supporting the magnet roller 206.

In the first embodiment, the magnetic roller 201 is biased against the wheel roller 202 by the spring 205, but in the second embodiment, the magnetic roller 201 is
, The magnet roller 206 urges the wheel roller 202 by its own magnetic force.

As a result, members such as springs and bearings are not required, and the cost can be reduced.

[0034]

As described above, claims 1 and 3,
According to the fourth, fifth and sixth aspects of the present invention, it is possible to improve the accuracy and cost of the thickness detecting device without using a conventional supporting member utilizing the principle of leverage. Further, it is possible to provide an image forming apparatus capable of printing an optimum image according to the thickness of the paper sheet. According to the second, sixth, seventh, eighth, and ninth aspects, it is possible to improve the accuracy of the thickness detecting device and further reduce the cost. Further, it is possible to provide an image forming apparatus capable of printing an optimal image according to the thickness of a sheet.

[Brief description of the drawings]

FIG. 1 is a sectional view of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic view of a thickness sensor according to the first embodiment of the present invention.

FIG. 3 is a control block diagram of the image forming apparatus according to the first embodiment of the present invention.

FIG. 4 is a schematic view of a thickness sensor according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional image forming apparatus.

[Explanation of symbols]

 Reference Signs List 201 magnetic roller 202 wheel roller 203 bobbin 123 paper sheet 206 magnet roller 208 oscillation circuit 105 engine controller

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Ishii 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Hirofumi Hori 3-30-2 Shimomaruko, Ota-ku, Tokyo F term (reference) in the company 2F063 AA16 BC09 BD17 DA02 DA05 EB25 GA03 LA05 2H027 DC02 DE04

Claims (9)

[Claims] 1. A thickness detection sensor comprising: a magnetic roller; and a wheel-shaped magnetic roller having a coil wound around an axle portion which is disposed so as to be in contact with the magnetic roller. 2. A thickness detection sensor comprising: a magnetized magnet roller; and a wheel-shaped magnetic roller in which a coil is wound around an axle portion that is disposed so as to be in contact with the magnet roller. 3. The apparatus according to claim 1, further comprising means for pressing said magnetic roller against said wheel-shaped magnetic roller.
Thickness detection sensor. 4. A paper sheet by forming a magnetic path between a magnetic roller and a wheel-shaped magnetic roller and passing the paper sheet through a pressure contact portion between the magnetic roller and the wheel-shaped magnetic roller. 4. The thickness detection sensor according to claim 3, wherein the inductance of the thickness detection sensor is changed according to the thickness of the sensor. 5. A thickness detecting device comprising: the thickness detecting sensor according to claim 4; and an oscillator using an inductance of the thickness detecting sensor, wherein the oscillation frequency of the oscillator is changed according to the thickness of the paper sheet. 6. An image forming apparatus comprising the thickness detecting device according to claim 5. 7. A paper sheet by forming a magnetic path between the magnetic roller and the wheel-shaped magnetic roller and passing the paper sheet through a pressure contact portion between the magnetic roller and the wheel-shaped magnetic roller. 3. The thickness detection sensor according to claim 2, wherein the inductance of the thickness detection sensor is changed according to the thickness of the thickness detection sensor. 8. A thickness detecting device, comprising: the thickness detecting sensor according to claim 7; and an oscillator using inductance of the thickness detecting sensor, wherein the oscillation frequency of the oscillator is changed according to the thickness of the paper sheet. 9. An image forming apparatus comprising the thickness detecting device according to claim 8.