JPH04169435A - Nip width detector, developing device and paper feeder - Google Patents

Abstract

PURPOSE:To obtain a development of high quality by providing a calculating means for calculating the width of a nip part based on the detection signal from a pressure sensor provided on a roller. CONSTITUTION:A pressure sensor 11 provided on a roller 5 is rotated following the rotation of the roller 5, and comes in pressure contact with an opponent roller 7 or to a pad, and then is in a free condition again, and rotates. Since the rotational speed is stable, by detecting the time for pressure welding of the pressure sensor 11, its interval of pressure contact, namely a nip width can be calculated by a calculating means 12.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a device for detecting the nip width of a mechanism in which rollers are brought into pressure contact with each other or rollers and a pad, and a developing device and a paper feeding device using the device. It is related to.

[Prior Art] Conventionally, a developing device of a copying machine has a structure as shown in FIG. That is, there is a casing 3 below the hopper 2 that stores the toner 1, and inside the casing 3, there is a developing roller 5 that supplies toner to the photosensitive tram 4. A layer thickness regulation blade 6 for regulation, a supply roller 7 for supplying the toner 1 to the developing roller 5, and the like are provided. As shown in the figure, the supply roller 7 supplies the toner 1 while being in pressure contact with the developing roller 5.

Further, a conventional paper feeding device of a copying machine has a structure as shown in FIG. That is, a separation roller 9 is provided below the upper paper feed roller 8. The paper 1o is sandwiched between the two rollers 8.9 and fed. The separation a-ra 9 rotates in the opposite direction to the paper feed roller 8 to prevent double feeding of paper.

[Problems to be Solved by the Invention] By the way, the supply roller 7 of the above-mentioned developing device is usually made of urethane foam or a fur brush, or if used for a long time, the developing roller 7 is made of urethane foam. 5
Depending on the friction between the fur brush and
The state of pressure contact between the developing roller 5 changes depending on the phenomenon of the hair falling down and the like. As a result, there is a problem that the supply power of the toner 1 deteriorates and the image density decreases.

Furthermore, due to molding distortions of the developing roller and supply roller of the developing device or assembly errors during assembly, the nip width between the developing roller 5 and the supply roller 7 may not be balanced on the left and right sides. As a result, there is a problem in that there is a difference in the supply power of the toner 1 between the left and right sides, resulting in uneven image density.

Furthermore, in the conventional paper feeding device of the copying machine described above, the paper feeding roller 8 and the separation roller 9 are pressed against each other in a symmetrical state, so that the paper may be conveyed diagonally. Conventionally, in order to correct this, a plurality of sets of supply rollers 8 and separation rollers 9 as described above have been provided, and the nip portions are dispersed so as to be as balanced as possible. Alternatively, a method is used in which the correction is not performed at the paper feed roller 8, but by providing a stopper downstream thereof.

However, although the method of preventing diagonal conveyance by dispersing the nip portion can correct the problem to some extent, it is not reliable. Furthermore, the method of correcting using a stopper is a secondary correction method in that it does not directly correct the imbalance between the paper feed roller 8 and separation roller 9.

The present invention aims to solve such conventional problems.

[Means for Solving the Problem] The present invention provides a pressure contact mechanism including a first roller and a 20th roller (or pad) that comes into pressure contact with the first roller. Input the pressure sensor installed on the roller and the detection signal from that pressure sensor,
The present invention is a nip width detecting device including a calculating means for calculating the width of the nip portion based on the calculated width.

The present invention also provides a casing, a developing roller disposed within the casing and supplying toner to the photosensitive drum;
In a developing device including a supply roller that is close to the developing roller and supplies toner to the developing roller, a plurality of pressure sensors are provided on the developing roller and/or the supply roller, and a detection signal from the pressure sensor is provided. a calculation means for calculating the width of the nip portion based on the input, an adjustment mechanism for adjusting the position of the supply roller, and a control means for controlling the adjustment mechanism based on the calculation result of the calculation means. This is a developing device equipped with

Furthermore, the present invention provides a paper feeding device that feeds paper and includes a first roller and a second roller (or pad) that is in pressure contact with the first roller. /
or a plurality of pressure sensors provided on the 20th roller;
a calculation means that inputs a detection signal from the pressure sensor and calculates the width of the nip portion based on the detection signal; and an adjustment mechanism that adjusts the position of the first roller and/or the second roller (or pad). , based on the calculation result of the calculation means,
and a control means for controlling the adjustment mechanism.

[Function] In the nip width detection device of the present invention, in accordance with the rotation of the roller, the pressure sensor provided therein rotates, comes into pressure contact with the mating roller or pad, and rotates again in a free state. Therefore, by detecting the time during which such a pressure sensor is in pressure contact, it is possible to calculate the pressure contact interval, that is, the nip width, using a calculating means, while the rotational speed is constant.

Further, in the developing device of the present invention, a plurality of pressure sensors provided on the developing roller and/or the supply roller rotate at the locations where the pressure sensors are provided, and detect a pressed state and a free state. Using the result, the calculation means calculates the nip width between the developing roller and the supply roller. Therefore, since the nip width at each location is known, the control means uses the adjustment mechanism to control the nip width to be balanced.

Further, in the paper feeding device of the present invention, a plurality of pressure sensors provided on the first roller and/or the 20th roller rotate at the locations where the pressure sensors are provided, and detect the pressed state and the free state. . Using the result, the calculation means calculates the nip width between the first roller and the second roller (or pad). Therefore, since the nip portion at each location is known, the control means utilizes the adjustment mechanism to control the nip width to be balanced.

[Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway side view showing the main parts of an embodiment of a developing device according to the present invention. In the figure, inside the casing 3, a developing roller 5, a layer thickness regulating plate 6,
A supply roller 7 is provided.

As shown in FIG. 2, this developing roller 5 has two
Pressure sensors 1111 are attached to the surface at several locations. As this pressure sensor 11, for example, a unimorph vibrator made by bonding a piezoelectric element and a metal plate is oscillated at a resonant frequency, and when a load such as pressure is applied to the vibrating surface, the oscillation output decreases, and conversely, the oscillation output decreases when a load such as pressure is applied to the vibrating surface. If there is no load and the vibrating surface is free, a pressure sensor with a large oscillation output can be used.

The calculation means 12 is a means for inputting detection signals from the two pressure sensors 11.11 and calculating the width of the nip portion between the developing roller δ and the supply roller 7 based on the detection signals.

That is, the developing roller 5 rotates at a circumferential speed of ■ and receives pressure from the supply roller 7 only at the nip portion, and the time t during which it is receiving that pressure is counted by the output signal from the pressure sensor 11. The nip width W is obtained as W=tXv. This nip width W is the nip width at the location where each pressure sensor 11 is present.

On the other hand, the shaft 71 of the supply roller 7, as shown in FIG.
It protrudes from the outside of the casing 3, and a roller 16 is attached to it. Casing 3 with its shaft 71 protruding
The hole 17 is a long hole facing the developing roller 5. Also, the casing 3 in the vicinity where the shaft 71 protrudes
A motor 14 is fixed to the motor, and a cam 15 is attached to the motor shaft.
is installed. The cam 15 is the above-mentioned C? 1
It is in contact with 6. These motor 14, cam 15, roller 16, long hole 17, etc. constitute an adjustment mechanism. Note that a similar motor and the like are provided on the opposite side of the casing 30.

The control means 13 is a means for recognizing the balance between the left and right nip widths W from each nip width W obtained by the calculation means 12, and outputting a control signal to the motor 14 so as to maintain the balance.

Next, the operation of the above embodiment will be explained.

When the developer roller 5 and supply roller 7 rotate, the two pressure sensors 11.11 on the developer roller 5 also rotate. Fourth
As shown in the figure, the pressure sensor 11 eventually reaches the nip portion. Then, at the nip part, pressure is applied,
Outputs a signal to that effect. After rotating for a while in this state, the pressure sensor 11 escapes from the nip portion as shown in FIG. Therefore, no pressure is applied.

The calculating means 12 receives such a signal from the pressure sensor 11, and calculates for each pressure sensor 11 using the formula W=tXv from the circumferential velocity V and the time t during which the pressure is being applied.
Calculate the nip width W. Then, calculate the balance between the left and right sides and the excess or deficiency of the absolute width.

The control means 13 looks at the calculation result from the calculation means 12, and
If there is an imbalance, one of the motors 14 attached to the casing 3 is rotated to correct it.

Due to this rotation, the cam 15 rotates, pushes the roller 16, and one end of the shaft 71 of the supply roller 7 moves toward the developing roller 5, for example. This corrects the imbalance in nip width W. Therefore, it is possible to prevent the toner 1 from being unbalancedly supplied due to the unbalance of the nip portion W between the developing roller 5 and the supply roller 7.

An embodiment of the paper feeding device of the present invention will now be described.

FIG. 6 is a side view showing the paper 10 being fed by the paper feed roller 8 and separation roller 9.

The width of the nip portion is W. Pressure sensors 18, 18 are attached to the left and right sides of the paper feed roller 8. As this pressure sensor 18, a unimorph vibrator made of a piezoelectric element and a metal plate laminated together as described above can be used.

The calculation means 19 is a means for inputting the detection signals from the two pressure sensors 18 and 18, and calculating the width of the nip portion between the paper feed roller 8 and the separation roller 9 based on the detection signals.

'That is, the paper feed roller 8 is rotating at a circumferential speed of V,
Since pressure is received from the separation roller 9 only at the nip portion, the time t during which the pressure is being received is measured by the pressure sensor 18.
The nip width W is determined as W:tXV. This nip portion W becomes a nip portion where each pressure sensor 18 is present.

The control means 20 is a means for recognizing the balance between the left and right nips @W from each nip @W obtained by the calculation means 19, and outputting a control signal to the adjustment mechanism 21 so as to maintain the balance.

The adjustment mechanism 21 is a mechanism that is provided on the shaft 91 of the separation roller 9 and moves the shaft 91 toward and away from the paper feed roller 8 . Specifically, it is constituted by means such as a cam or a roller as shown in FIG. 3, for example.

Next, the operation of the above embodiment will be explained.

When the paper feed roller 8 and the separation roller 9 rotate, the two pressure sensors 18,18 on the paper feed roller 8 also rotate. 8th
As shown in the figure, the pressure sensor 18 eventually reaches the nip portion. Then, at the nip part, pressure is applied,
Outputs a signal to that effect. After rotating for a while in this state, the pressure sensor 18 escapes from the nip portion as shown in FIG. Therefore, no pressure is applied.

The calculating means 19 receives such a signal from the pressure sensor 18, and calculates for each pressure sensor 18 using the formula W=tXv from the circumferential velocity V and the time t during which the pressure is being applied.
Calculate the nip width W. So.

Then, calculate the balance between the left and right sides and the excess or deficiency of the absolute width.

The control means 20 looks at the calculation result from the calculation means 19, and
If there is an imbalance, the adjustment mechanism 21 is controlled to correct it. As a result, one end of the shaft 91 of the separating roller 9 moves toward the paper feed roller 8, for example. As a result, the imbalance in the nip portion W is corrected. Therefore, it is possible to prevent the paper from being skewed due to the imbalance in the nip portion W between the paper feed roller 8 and the separation roller 9.

Note that if the paper has already been conveyed diagonally upstream from the location where the paper feed roller 8 and separation roller 9 are located, in order to correct the diagonal conveyance, the paper feed roller 8 and separation roller 9 are intentionally moved. It is also possible to make the nip gW unbalanced.

The nip width W may be made unbalanced on the left and right sides so that the paper is fed diagonally in the direction opposite to the diagonal direction detected by the sensor.

Furthermore, instead of the separation roller 9, a separation pad may be used.

Moreover, the number of pressure sensors of the present invention is not limited to two, and more than two may be provided. Further, it may be provided on either roller or both rollers.

Further, the adjustment mechanism of the present invention is not limited to one using the rollers, cams, motors, etc. described above, and may be any mechanism that can adjust the nip width.

Further, the calculation means and control means of the present invention may be realized in software using a microcomputer, or may be realized using a dedicated hardware circuit having these functions.

[Effects of the Invention] As is clear from the above description, the nip width detection device of the present invention can calculate the width of the nip portion based on the detection signal from the pressure sensor provided on the roller.

Further, in the developing device of the present invention, a plurality of pressure sensors provided on the developing roller and/or the supply roller ζ rotate at the location where the developing roller and/or the supply roller ζ are provided, and detect a pressed state and a free state,
A calculation means calculates the nip portion between the developing roller and the supply roller. Therefore, since the nip width at each location is known, the nip width can be balanced and high-quality development can be performed.

Further, in the paper feeding device of the present invention, a plurality of pressure sensors provided on the tenth roller and/or the second roller rotate at the locations where the pressure sensors are provided, and detect a pressed state and a free state. , the nip width between the first roller and the second roller (or pad) is calculated.

Therefore, since the nip width at each location is known, the nip width can be balanced and oblique sheet feeding can be eliminated.

[Brief explanation of drawings]

FIG. 1 is a schematic partially cutaway sectional view showing an embodiment of a developing device according to the present invention, FIG. 2 is a perspective view of a developing roller of the embodiment, and FIG. FIG. 4 and FIG. 5 are side views for explaining the operation of the adjustment mechanism; FIG. 6 is a side view for explaining one embodiment of the paper feeding device according to the present invention; Figure 7 is a front view of the same embodiment, and Figure 8 is a front view of the same embodiment.
9 and 9 are front views for explaining the operation of the same embodiment, FIG. 10 is a schematic sectional view showing an example of a conventional developing device, and FIG. 11 is an example of a conventional paper feeding device. FIG. DESCRIPTION OF SYMBOLS 1... Toner, 3... Casing, 4... Photosensitive tram, 5... Developing roller, 7... Supply roller, 8...
... Paper feed roller, 9 ... Separation roller, 10 ... Paper, 11.18 ... Pressure sensor, 12.19 ... Calculation means, 13.20 ... Control means, 14, 15 16
, 17.21...adjustment mechanism.

Claims (3)

[Claims] (1) A pressure sensor provided on the first roller and/or second roller of a pressure contact mechanism that includes a first roller and a second roller (or pad) that comes into pressure contact with the first roller. What is claimed is: 1. A nip width detection device comprising: a calculation means for inputting a detection signal from the pressure sensor and calculating the width of the nip portion based on the detection signal. (2) A developing device including a casing, a developing roller disposed within the casing and supplying toner to the photosensitive drum, and a supply roller proximate to the developing roller supplying toner to the developing roller, a plurality of pressure sensors provided on the developing roller and/or the supply roller; a calculation means for inputting a detection signal from the pressure sensor and calculating the width of the nip portion based on the detection signal; A developing device comprising: an adjustment mechanism that adjusts a position; and a control device that controls the adjustment mechanism based on a calculation result of the calculation device. (3) In a paper feeding device that feeds paper and includes a first roller and a second roller (or pad) that presses against the first roller, the first roller and/or the second roller a plurality of pressure sensors provided on the roller; a calculation means for inputting a detection signal from the pressure sensor and calculating the width of the nip portion based on the detection signal; and the first roller and/or the second roller. (or a pad); and a control means that controls the adjustment mechanism based on the calculation result of the calculation means.