JP2001083840A - Belt meandering suppression device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the meandering of a belt in a wider range by constituting a belt position detection means by a swing abutting member and plural sensors for individually measuring the displacement of the plural positions of different distances from a spindle in the arm part to be detected of the swing abutting member. SOLUTION: The belt position detection means is provided with the swing abutting member 63 in a thin and long plate shape provided with an abutting arm part abutted to the side end part of the belt 21 (41) and swung around the spindle 60 parallel to the circulating direction B (or C) of the belt 21 swung following the movement in the width direction of the belt and the arm part to be detected swung around the spindle 60 linked with the swing of the abutting arm part. Also, it is provided with two first and second sensors 64 and 65 for respectively measuring the displacement of the two positions G1 and G2 of the different distances from the spindle 60 in the arm part to be detected of the swing abutting member 63. As a result, the meandering of the belt is more surely and accurately suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a belt meandering suppressing device for suppressing meandering occurring in a width direction orthogonal to a belt circling direction, and particularly to a copier, a printer, a facsimile, a multifunction machine, and the like. The present invention relates to a belt meandering suppressing device suitable for suppressing meandering of a belt member used for image formation in an image forming apparatus to be used.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine or a printer using an electrophotographic method, a belt member such as a photosensitive belt, an intermediate transfer belt, and a sheet conveying belt which are stretched around a plurality of rolls and used are used. In the case where this type of belt is used, a belt meandering suppressing device for suppressing meandering that occurs in a width direction orthogonal to the circumferential direction of the belt is generally employed. This is because, for example, when a plurality of toner images are overlapped to form a color image or the like, if the belt moves in the width direction due to meandering of the belt, the toner images are shifted and overlapped to cause color shift or color unevenness. , Image quality defect such as image shift occurs,
It has been adopted to avoid this.

As the main belt meandering suppressing device, for example, a belt position detecting means for detecting a position in a width direction of the belt and a belt based on position information detected by the belt position detecting means are used. There is known a device provided with belt displacing means for displacing in the width direction and returning to a specified position.

More specifically, as a belt position detecting means, as shown in FIG. 14A, the belt a is brought into contact with a side end of the belt a so that the center of the support shaft b follows the movement of the belt a in the width direction. Contact member c that oscillates, and this contact member c
And a sensor f for measuring a displacement accompanying a swing of the detected portion e located on the opposite side of the support shaft b with respect to the contact portion d with the belt a. G in the drawing indicates a biasing spring. Further, as shown in FIG. 14B, the belt position detecting means is arranged so as to sandwich the side end of the belt a and is divided into upper and lower portions, and a plurality of lights arranged in the width direction of the belt a are detected by the belt side. A light-emitting portion h composed of an LED or the like that emits light toward the camera, and a CCD that receives light not emitted by the belt among light emitted from the light-emitting portion.
And a light receiving unit i composed of the above. On the other hand, as the belt displacing means, a deviation amount (meandering amount) from a specified position is calculated based on the position information obtained by the belt position detecting means, and a belt is stretched to eliminate the deviation amount. A mechanism is used in which a belt is returned to a normal position by inclining one roll by a predetermined amount.

[0005]

However, in such a conventional belt meandering suppressing device, the detection range M of the belt position detecting means (mainly a sensor) is relatively narrow, and this detection range is, for example, ±. Xmm, ± X
The belt position can be corrected by the belt displacement means only within the range of mm, and the amount by which the belt position can be corrected is relatively small. For this reason, when the belt moves even slightly beyond its detection range, for example, when the belt is worn or replaced, the belt is immediately detected as abnormal, and the device stops, resulting in an inconvenient surface. .

Incidentally, in Japanese Patent Application Laid-Open Nos. 9-48533 and 9-169449, the belt meandering to the end of the roll due to meandering is quickly returned to a specified position on the center of the roll. There has been proposed a belt meandering suppressing device which switches a control amount or a control table for correcting a belt position according to the belt meandering.
However, in the case of such an apparatus, since the detection range of the belt position itself is not widened, there is a possibility that the apparatus cannot cope with a large movement of the belt. Could not be the appropriate solution to do so.

The present invention has been made in view of such circumstances, and an object of the present invention is to detect a displacement in a belt width direction due to meandering of a belt in a wider range. An object of the present invention is to provide a belt meandering suppressing device capable of suppressing meandering in a wider range.
In addition, while the belt position can be detected with higher accuracy for the belt displacement within a range close to the specified position, the belt position can be detected for the belt displacement within a range far from the specified position. It is an object of the present invention to provide a belt meandering suppressing device capable of detecting a belt position and suppressing meandering with extremely high efficiency, which is capable of detecting a wider range of displacement even if the detection accuracy is low.

[0008]

According to a first aspect of the present invention, there is provided a belt meandering restraining apparatus for achieving the above object in a width direction orthogonal to a circumferential direction of a belt stretched around a plurality of rolls and rotating. In a belt meandering suppressing device, comprising: belt position detecting means for detecting a position; and belt displacing means for displacing the belt in the width direction based on the position information detected by the belt position detecting means and returning the belt to a specified position. A contact arm that abuts the side end of the belt and swings about a support shaft following the movement of the belt in the width direction; A swing abutting member having a detected arm that swings about the support shaft in conjunction therewith, and displacements at a plurality of positions at different distances from the support shaft in the detected arm portion of the swing abutment member. Individually And it is characterized in that it is composed of a plurality of sensors for measuring.

According to the belt meandering suppressing device of the first invention, the displacement of the swinging contact member due to the swing of the detected arm portion varies depending on the distance from the support shaft. By measuring the displacement of each position having a different distance from the support shaft at a plurality of sensors, the detection range is widened. In addition, the larger the separation distance of the detected arm from the support shaft, the larger the swing radius, and more sensitively to a small displacement of the belt, resulting in a large displacement, and conversely, a distance from the support shaft. The smaller the distance, the smaller the swing radius, and the response to a large displacement of the belt becomes slow, but the displacement is small. For this reason, the position of the belt can be detected with a detection accuracy corresponding to the amount of displacement of the belt by appropriately switching and using a plurality of sensors that respectively measure the displacement of each position of the detected arm portion. Becomes Here, the support shaft of the swinging contact member is usually arranged so as to be parallel to the circling direction of the belt, but the swinging contact member (the contact arm portion) surely follows the movement in the width direction of the belt. The arrangement is not particularly limited as long as it can swing. This is the same in the case of a first support shaft and the like described later.

According to a second aspect of the present invention, there is provided a belt meandering suppressing device according to the present invention, wherein the belt position detecting means in the belt meandering suppressing device according to the first invention is replaced by a side end portion of the belt. Contact arm that swings about the support shaft following the movement of the belt in the width direction, and swings about the support shaft in conjunction with the swing of the contact arm, and A swing contact member having a detected portion on which a plurality of types of detected curved surfaces having different displacement amounts when passing through the same position, and displacements of different detected curved surfaces in the detected portion of the swing contact member And a sensor for measuring the position of the belt.

According to the belt meandering suppressing device of the second invention, the displacement of each of the detected curved surfaces of the detected portion with respect to the swing angle of the swing contact member is different. By configuring so that the amount of displacement of the detected curved surface when the swing angle is large is small, the detection range is widened even though the measurement is performed by one sensor. In addition to the configuration of the detected curved surface, if the amount of displacement of the detected curved surface is increased when the belt movement amount is small and the swing angle of the swing contact member is small, the displacement with respect to the swing angle is increased. The detected surface with a large amount reacts more sensitively to a small displacement of the belt and displaces greatly.On the contrary, the detected surface with a small displacement with respect to the swing angle responds greatly to a large displacement of the belt, Displaces small. For this reason,
By detecting each curved surface having a different displacement amount with respect to the swing angle in accordance with the movement amount of the belt and appropriately forming the curved surface continuously, the belt position can be detected with a detection accuracy according to the belt displacement amount. It is possible to do.

Further, a belt meandering suppressing device according to the present invention (third invention) for achieving the above object is a belt meandering suppressing device according to the first invention, wherein the belt position detecting means is replaced with a side end portion of the belt. Contact arm that swings about the first support shaft following the movement of the belt in the width direction, and swings about the first support shaft in conjunction with the swing of the contact arm. A swing contact member having a detected arm portion to be detected, and a first support shaft of the swing contact member is fixed, and a swing range of the contact member swinging on the first support shaft is regulated. A pair of left and right stop members are provided to stop the swing of the contact member at the regulating position, and the first support shaft is located at a position different from the first support shaft while supporting the swing contact member. A swing support that swings about a parallel second support shaft When, is characterized in the use of belt position detection means is composed of a sensor for measuring the displacement of the sensing arm portion of the swinging abutment member supported on the oscillating supporting member.

According to the belt meandering restraining apparatus of the third invention, the swing contact member swings on the first support shaft, and after the swing contact member is stopped by the stop member, the first support is stopped. Since the swing support member for fixing the shaft swings on the second support shaft, the swing abutment member eventually swings about the two support shafts, and the displacement amount of the swing abutment member also increases in two stages. .
As a result, the detection range is widened in spite of measurement by one sensor. In addition, when the swing contact member swings on the first support shaft, the detection arm portion is more sensitively reacted to a small displacement of the belt and largely displaced,
On the other hand, when the swing support member swings on the second support shaft, the detection arm of the swing support member responds to a large displacement of the belt, but displaces slightly. For this reason, by setting so that the swing contact member swings on the first support shaft and the swing support member swings on the second support shaft as appropriate according to the displacement amount of the belt, the displacement of the belt is improved. It is possible to detect the position of the belt with the detection accuracy according to the amount.

[0014]

[First Embodiment] FIG. 1 is a schematic view showing a color image forming apparatus to which the present invention (first invention) is applied, and FIG. 1A is an intermediate transfer belt as a belt member 1. 21B illustrates an example in which the present invention is applied as a belt meandering suppressing device in an intermediate transfer belt mechanism that drives the belt 21, and FIG. 2B illustrates an example in which the present invention is applied as a belt meandering suppressing device in a sheet conveying belt mechanism that drives a sheet conveying belt 41 as the belt member 1. FIG. 2 is a schematic perspective view showing the entirety of an intermediate transfer belt mechanism or a sheet conveying belt mechanism to which the belt meandering suppressing device is applied.

In the image forming apparatus shown in FIG. 1A, the intermediate transfer belt 21 of the intermediate transfer belt mechanism 20 is
Drive roll 22, driven roll 23, tension roll 2
4 and the backup roll 25, and is rotated in the direction of arrow B by the rotational power of the drive roll 22. Then, the intermediate transfer belt mechanism 20
Below, four image forming units 10Y, 10M, 10C, which respectively form four color toner images of yellow (Y), magenta (M), cyan (C), and black (k) by an electrophotographic process. 10K are arranged, and the four toner images formed by the respective image forming units 10 are multiplex-transferred so as to be superimposed on the intermediate transfer belt 21.

That is, any of the image forming units 10
Also, after the photosensitive drum 11 rotating in the direction of the arrow A is uniformly charged by the charging device 12 of the roll type, a laser beam corresponding to the color-separated image data from the latent image forming device 13 is formed on the charged surface. (Dotted arrow) is scanned and exposed to write an electrostatic latent image. Thereafter, the latent image is developed with a developer supplied from the developing device 14 to become a toner image. The four toner images formed on the drum 11 are sequentially primary-transferred to the surface of the intermediate transfer belt 21 between the photosensitive drum 11 and the transfer device 15 of a roll type. The surface of the photosensitive drum 11 after the transfer is cleaned by the blade of the drum cleaner 16. Then, the intermediate transfer belt 2
The recording sheet conveyed at a predetermined timing by the registration roll 30 or the like to the secondary transfer position where the secondary transfer roll 26 disposed opposite to the backup roll 25 is disposed at a predetermined timing. P is secondarily transferred to P. Then, the recording sheet P to which the toner image has been transferred is sent so as to pass through the nip portion between the heating roll 36 and the pressure roll 37 in the roll nip type fixing device 35, and the toner image is thermally fixed. Through the above process, a color image is formed on the recording sheet P.

On the other hand, in the image forming apparatus shown in FIG. 1B, the sheet conveying belt 41 of the sheet conveying belt mechanism 40 is stretched around a driving roll 42, a driven roll 43, a tension roll 44, and a backup roll 45. The drive roll 42 rotates in the direction of arrow C by the rotational power. Further, four image forming units 10Y, 10M, 10C, and 10K that respectively form toner images of four colors are arranged above the sheet conveying belt mechanism 40, as in the case of the image forming apparatus. The four toner images formed by the image forming units 10 are multiplex-transferred so as to be superimposed on the recording sheet P conveyed by being attracted to the sheet conveying belt 41.

That is, as in the case of the image forming apparatus, each photosensitive drum 11 in each image forming unit 10
After four toner images are respectively formed on the recording sheet P, the toner images are multiplexed so that the toner images are superimposed on the recording sheet P conveyed by being electrostatically adsorbed to the sheet conveying belt 41 by the sheet adsorbing device 46. Transcribed. Then, the recording sheet P on which the toner image has been transferred is separated from the sheet conveying belt 41 near the backup roll 45, and then sent to a roll nip type fixing device 35, where the toner image is thermally fixed. Through the above process, a color image is formed on the recording sheet P. FIG. 1a, b
Each one-dot chain line in the drawing indicates the transport path of the recording sheet P.

The intermediate transfer belt mechanism 20 (or the sheet conveying belt mechanism 40) is provided with a belt meandering suppressing device 50 as shown in FIGS.

As shown in FIG. 2, the belt meandering suppressing device 50 according to the first embodiment sets the position of the intermediate transfer belt 21 (or the sheet conveying belt 41) in the width direction E orthogonal to the circumferential direction B (or C). Belt position detecting means 5 for detecting
1 and a belt displacing means 52 for displacing the belt 21 (41) in the width direction based on the position information detected by the belt position detecting means 51 and returning it to a specified position.

The belt position detecting means 51 contacts the side end portion 21a (41a) of the belt 21 (41) and swings following the movement of the belt in the width direction E.
The contact arm 61 swings around a support shaft 60 parallel to the rotation direction B (or C) of the first position, and a detected object swings around the support shaft 60 in conjunction with the swing of the contact arm 61. An elongated plate-shaped swing contact member 63 having an arm portion 62
And two positions G1, at which the distance L from the support shaft 60 in the detected arm portion 62 of the swing contact member 63 is different.
It is composed of two first sensors 64 and a second sensor 65 for measuring the displacement of G2. Reference numeral 66 in FIG. 3 indicates that the arm 62 to be detected of the swinging contact member 63 is pulled with a relatively low tension, whereby the contact arm 6
1 is always the belt end 2 even when the belt is moving.
The biasing spring is biased so as to keep elastic contact with 1a (41a).

The swing contact member 63 is connected to the belt 21 (4
When the belt 21 (41) moves in the width direction E <b> 1 when the belt 21 (41) moves in the width direction E <b> 1 when the belt 21 (41) is in the regular specified position N without meandering, the vertical axis is set. Swing so as to incline in the direction of arrow J. Conversely, belt 21
When (41) moves in the width direction E2, the support shaft 60
Swinging around the center in the direction of arrow K. Further, the first sensor 64 and the second sensor 65
Are irradiated with light (dotted line) toward the detected arm portion 62 of the swinging contact member 63, and the light is reflected by the detected arm portion 62 to receive the reflected light. After measuring the displacement of the arm portion 62, the belt 21
(41) An optical sensor capable of detecting the position in the width direction E.

The first sensor 64 is supported on the support shaft 60 by the same distance L1 from the center point (O) of the support shaft 60 to the contact position of the contact arm 61 with which the belt-side end contacts. The second sensor 65 is installed so as to measure the displacement of the position G1 of the detected arm 62 away from the center point (O) of the second sensor 60. For example, the second sensor 65 has a separation distance L2 (= L1) that is half the separation distance L1. / 2) is provided so as to measure the displacement of the position G2 of the detected arm portion 62 that is separated from the center point (O) of the support shaft 60 by (/ 2). Further, the first sensor 64 is, for example, the center of the support shaft 60 by the same distance as the separation distance L1 from the center point (O) of the support shaft 60 to the contact position of the contact arm portion 61 with which the belt-side end contacts. The second sensor 65 is installed so as to measure the displacement of the position G1 of the detected arm 62 away from the point (O), and the second sensor 65 has a separation distance L2 (= L1 / 2) that is, for example, half the separation distance L1. It is installed so as to measure the displacement of the position G <b> 2 of the detected arm 62 apart from the center point (O) of the support shaft 60 only.

On the other hand, the belt displacing means 52
The belt 21 (41) is displaced in the width direction E by displacing the tension roll 24 of the plurality of rolls supporting (41) in, for example, the vertical directions Q and R at one end thereof. This tension roll 2
A displacement (steering) mechanism 53 for displacing the tension roll 4 in the vertical directions Q and R supports one end of the tension roll 24 on an eccentric cam 54 which is rotated by a motor 54 in a predetermined direction by a predetermined amount. By rotating 54, one side of the tension roll 24 can be displaced by a predetermined amount in the vertical directions Q and R thereof.

The belt displacing means 52 employing the steering mechanism 53 transmits the belt position information obtained by the belt position detecting means 51 to the control device 56 and performs predetermined processing. It is sent to a drive circuit 57 that drives a motor in the steering mechanism 53, and is operated by this. That is, when the detection information of the belt position is input, the control device 5
6, the current position of the belt is calculated by the position calculation unit 56a, and based on the calculation result, the current position of the belt is compared with the specified position N by the control processing unit 56b. Is obtained, and a control signal corresponding to the amount of belt displacement is sent to the drive circuit 57. Each of the drive rolls 22 (42) has, for example, a rotational drive force of the drive motor 38,
9 to rotate.

Next, the operation of the belt meandering suppressing device 50 will be described.

First, when the belt 21 (41) is at the specified position N, as shown in FIG.
Since the swing contact member 63 of 1 (60) is in a vertical state,
At this time, the output of the first sensor 64 (for example, when a sensor having an output of 0 to 5 V is used) is "2.
5V ". In this state, the control device 53 recognizes that the belt is at the normal specified position N, and as a result, the belt displacement means 52 does not operate.

When the belt 21 (41) moves in the width direction E1 or E2 due to the meandering, FIG.
As shown in FIG. 5, following the movement of the belt, the contact arm portion 61 of the swing contact member 63 swings around the support shaft 60 in the direction of arrow J or the direction of arrow K, and interlocks with the swing. Similarly, the detected arm portion 62 is rotated around the support shaft 60 by an arrow J.
Swings in the direction or the arrow K direction and is displaced. Then, the displacement of the detected arm 62 at this time is measured by the first sensor 64 or the second sensor 65.

In the first embodiment, the belt 21
When the movement in the width direction of (41) is within a range close to the prescribed position N (when the swing angle of the swing abutment member 63 is within the range of 0 to ± θ), the displacement of the detected arm portion 62 Is measured by the first sensor 64, and when the movement of the belt 21 (41) in the width direction is larger than that (when the swing angle of the swing contact member 63 is in the range of + θ to + 2θ or -θ to -2θ). Is set so that the displacement of the detected arm portion 62 is measured by switching to the second sensor 65.

FIG. 4 shows the swing angle (θ) of the swing contact member 63 and the positions G1, G2 of the detected arm 62 at this time.
3 shows a relationship between the first sensor 64 and the second sensor 65 for measuring the respective displacement amounts and the respective displacement amounts. FIG. 5 shows the relationship between the swing state of the swing contact member 63 and the sensor output value with respect to each belt meandering amount.

4 and 5, the displacement of each of the positions G1 and G2 of the detected arm portion 62 is determined by two sensors 64,
By performing the measurement in a shared manner by the use of the first sensor 64, the detection range of the belt position is widened as compared with a case where the displacement amount is measured only by one of the first sensors 64, for example. In other words, only the first sensor 64 can measure, for example, the total displacement (2 W) of the position G1 of the detected arm 62 corresponding to the swing of the swing contact member 63 by ± θ. By measuring the displacement of the position G2 of the detected arm 62 by the 2 sensor 65, for example, the displacement of the position G1 of the detected arm 62 corresponding to the swing of the swinging contact member 63 by ± 2θ can be obtained. The measurement can be performed by measuring the amount of displacement (2S) of the position G2 in the detected arm portion 62.

When the movement of the belt 21 (41) in the width direction is within a range close to the prescribed position N, the displacement of the swing contact member 63 at the position G1 far from the support shaft 60 of the detected arm portion 62. The position of the belt 21 (41) (slight change) can be detected with high accuracy by measuring the delicate displacement with the first sensor 64 because the position of the belt 21 (41) is increased quickly and quickly. Thus, the belt displacement means 52 can be controlled based on the highly accurate belt position detection information.
Can be operated, so that the meandering of the belt occurring near the displacement regulation position N can be more accurately suppressed.

On the other hand, if the movement of the belt 21 (41) in the width direction is largely separated from the vicinity of the specified position N, the movement of the belt 21 (41) is not substantially changed but the support of the detected arm portion 62 of the swinging contact member 63 is replaced. Since the displacement of the position G2 close to the shaft 60 is small, by measuring the large displacement with the second sensor 65, it is possible to reliably detect even the position of the belt 21 (41) which has greatly changed. This allows
Even if there is a significant change in the belt position, the change is detected, so that the belt can be surely returned to the specified position N by the operation of the belt displacement means 52.

Therefore, the belt meandering suppressing device 50
According to the method described above, the belt position can be detected with higher accuracy with respect to the displacement of the belt within a range close to the specified position N, while the belt position can be detected within a range far from the specified position N. In other words, even if the detection accuracy of the belt position is low, it is possible to detect a wider range of displacement, so that it is possible to detect the belt position and suppress meandering very efficiently.
As a result, the meandering of the belt is more reliably and accurately suppressed, so that the intermediate transfer belt 21 and the sheet transport belt 4
No image quality defects such as color shift, color unevenness, and image shift caused by the meandering 1 occur.

[Second Embodiment] FIG. 6 shows a belt position detecting means according to another embodiment to which the present invention (second invention) is applied.
6 is the same as that of the first embodiment except that a belt position detecting means 70 shown in FIG.

The belt meandering device 5 according to the second embodiment
As shown in FIG. 6, the belt position detecting means 70 of the belt 21 abuts on the side end 21a (41a) of the belt 21 (41) and swings following the movement of the belt 21 in the width direction E. A contact arm 72 that swings about a support shaft 71 parallel to the rotation direction B (or C), and the contact arm 72
In the form of a deformed sector in which a plurality of types of detected curved surfaces 73a, 73b, and 73c having different amounts of displacement when passing through the same position due to the swing are formed in association with the swing of the support shaft 71. The swing contact member 75 includes a swing contact member 75, and one sensor 76 that measures the displacement of each of the different detected curved surfaces 73 a, 73 b, and 73 c in the detected portion 74 of the swing contact member 75. Reference numeral 77 in FIG. 6 indicates that the contact arm 72 of the swinging contact member 75 is pulled with relatively low tension, whereby the contact arm 72 always moves its belt side end 21a (even when the belt moves). 41a)
This is a biasing spring that is biased so as to keep elastic contact with the spring.

The swing contact member 75 is similar to the swing contact member 63 (FIG. 3) of the first embodiment, and is similar to the belt 21.
When (41) does not meander and is at the regular specified position N, the belt 21 (41) is set to be in a vertical state.
Swings in the width direction E1 so as to tilt in the direction of arrow J about the support shaft 60, and conversely, the belt 2
1 (41) is moved in the width direction E2.
It swings so as to incline in the direction of arrow K about 0. The sensor 76 is also an optical sensor similar to the first sensor 64 and the second sensor 65 in the first embodiment.

Each of the detected curved surfaces 73a, 73b, 73 of the detected arm 74 in the swing contact member 75.
c, the displacement amounts (W, S) when passing through the same position due to the swing of the swing contact member 75 (when crossing the light 76a emitted from the sensor 76 as shown by the dotted line in FIG. 6) are different (C). W> S), as shown in FIG. 5, the rate of change of the swing radius from the center point (O) of the support shaft 71 is changed in accordance with the swing angle (θ). That is, the first detected curved surface 73a is formed into a curved surface having a characteristic of being significantly displaced (± W) by the swing of the swing contact member 75, and the second detected curved surface 73b is formed.
Is a curved surface having a characteristic of being slightly displaced (−S) by the swing of the swing contact member 75 in the direction of the arrow K, and the third detected curved surface 73c is slightly caused by the swing of the swing contact member 75 in the direction of the arrow J. Each is formed on a curved surface having a characteristic of displacing (-S).

Next, the operation of the belt meandering suppressing device 50 using the belt position detecting means 70 will be described.

First, when the belt 21 (41) is at the prescribed position N, the swing contact member 75 of the belt position detecting means 70 as shown in FIG.
Since the contact arm portion 72 is in a vertical state, the output of the sensor 76 (when using a sensor having an output of 0 to 5 V) at this time indicates "2.5 V" as shown in FIG.
In this state, the control device 53 recognizes that the belt is at the normal specified position N, and as a result, the belt displacement means 52 does not operate.

When the belt 21 (41) moves in the width direction E1 or E2 due to the meandering, FIG.
As shown in FIG. 7, following the movement of the belt, the contact arm 72 of the swing contact member 75 swings around the support shaft 71 in the direction of arrow J or the direction of arrow K, and interlocks with this swing. Similarly, the detected part 74 is displaced by swinging about the support shaft 71 in the arrow J direction or the arrow K direction. Each of the detected curved surfaces 73a, 73b, 73c in the detected portion 74 at this time.
Is measured by the sensor 76.

FIG. 7 shows the swing angle (θ) of the swing contact member 75 at this time and each detected curved surface 73 in the detected portion 74.
a, 73b, 73c, and the relationship between the displacement amounts (W, S), and the respective displacement amounts, and sensors 76 for measuring the respective displacement amounts.
It shows the relationship with. FIG. 8 shows the relationship between the swing state of the swing contact member 75 and the sensor output value with respect to each belt meandering amount.

7 and 8 that the detected portion 62 is formed by a plurality of detected curved surfaces having different displacement amounts as described above, so that the displacement amount with respect to the swing angle is the same as in the first embodiment. The amount of displacement is larger than the displacement amount in the case of the mere linear detected arm portion 62, and the detection range of the belt position is widened. In other words, particularly when the swing contact member 75 swings greatly, the second and third detected curved surfaces 73b and 73c having a small displacement amount of the detected portion 74 cause the belt to greatly fluctuate and swing. Even when the contact member 75 swings greatly, the two detected curved surfaces 7
By 3b and 73c, the displacement amount at that time can be measured.

When the movement of the belt 21 (41) in the width direction is within a range close to the specified position N (the swing contact member 7).
5 is in the range of 0 to ± θ), since the sensor 76 measures the displacement of the first detected curved surface 73a having a large displacement with respect to the swing angle,
1 (41) (small fluctuation) can be detected with high accuracy. Thereby, the belt displacement means 52 can be operated based on the highly accurate detection information of the belt position, so that the meandering of the belt occurring near the prescribed displacement position N can be more accurately suppressed.

On the other hand, when the movement of the belt 21 (41) in the width direction is greatly separated from the vicinity of the prescribed position N and large (the swing angle of the swing contact member 75 is + θ to + 2θ or -θ to -2θ).
), The second or third detected curved surfaces 73b, 73c having a small displacement amount for the large movement.
Is measured by the sensor 76, it is possible to reliably detect even the position of the belt 21 (41) that has greatly changed. As a result, even if there is a significant change in the belt position, the change is detected, so that the belt can be surely returned to the specified position N by the operation of the belt displacement means 52.

Therefore, the belt position detecting means 70
The same effect as in the first embodiment described above can also be obtained with the belt meandering suppressing device 50 using.

[Embodiment 3] FIG. 9 shows a belt position detecting means according to another embodiment to which the present invention (third invention) is applied.
Is the same as that of the first embodiment except that a belt position detecting means 80 shown in FIG. 9 is used in place of the belt position detecting means 60 in the belt meandering device 50 in FIG.

The belt meandering device 5 according to the third embodiment
As shown in FIG. 9, the belt position detecting means 80 of the belt 21 which abuts on the side end 21a (41a) of the belt 21 (41) and swings following the movement of the belt 21 in the width direction E. A contact arm 82 that swings about a first support shaft 81 parallel to the rotation direction B (or C), and an object that swings about the first support shaft 81 in conjunction with the swing of the contact arm 82. An elongated flat plate-shaped swing contact member 84 having a detection arm portion 83, and a first support shaft 81 of the swing contact member 84, which is fixed and swings about the first support shaft 81. A pair of left and right stop members (stoppers) 85a and 85b for stopping the swinging of the contact member 84 at the regulating positions so as to regulate the swing range of the 84 are provided, and the swing contact member 84 is supported. At a position different from the first support shaft 81 Of a plate-shaped swing support member 87 swinging about a second support shaft 86 parallel to the first support shaft 81, and a detected arm portion 83 of a swing contact member 84 supported on the swing support member 87. And a sensor 88 for measuring displacement.

Reference numeral 89 in FIG. 9 is a support member for fixing the second support shaft 86. Reference numeral 90 denotes a contact arm 82 of the swinging contact member 84 which is pulled by a relatively weak tension so that the contact arm 82 always moves to the belt-side end 21a (41a) even when the belt moves. This is a biasing spring that is biased so as to keep elastic contact. Further, reference numerals 91 and 92 denote swing support members 87.
The lower side of the second support shaft 86 is pulled with relatively low tension, so that the swing support member 87 is in a neutral state and is balanced so as to swing about the second support shaft 86. It is a spring for maintaining balance. The spring constant K1 of the biasing spring 90 and the spring constants K2 and K3 of the balance holding springs 91 and 92 are determined.
Is greater than or equal to “K1 <K2 + K3 (where K2 = K
3) ".

The oscillating contact member 84 is similar to the oscillating contact member 63 (FIG. 3) in the first embodiment, and is similar to the belt 21.
When (41) does not meander and is at the regular specified position N, the belt 21 (41) is set to be in a vertical state.
Is moved in the width direction E1 so as to tilt in the direction of arrow J about the first support shaft 81 (FIG. 10).
a) Conversely, when the belt 21 (41) moves in the width direction E2, the belt 21 (41) swings so as to incline in the direction of arrow K about the first support shaft 81 (FIG. 11a).
When the belt 21 (41) moves significantly in the width direction E <b> 1 and the swing contact member 84 hits the stop member 85 a and stops, the swing support member 87 stops moving.
Further, the belt 21 (41) swings so as to incline in the direction of the arrow J around the center 6 (FIG. 10b).
When it stops by hitting b, it swings so as to further tilt in the direction of arrow K about the second support shaft 86 (FIG. 11B). Further, the sensor 88 is also an optical sensor similar to the first sensor 64 and the second sensor 65 in the first embodiment.

Next, the operation of the belt meandering suppressing device 50 using the belt position detecting means 80 will be described.

First, when the belt 21 (41) is at the specified position N, the swing contact member 84 of the belt position detecting means 80 as shown in FIG.
Since the contact arm 82 is in a vertical state, the output of the sensor 98 (when a sensor having an output of 0 to 5 V is used) at this time is "2.5 V" as shown in FIG. In this state, the controller 53 recognizes that the belt is at the normal specified position N.
As a result, the belt displacement means 52 does not operate.

When the belt 21 (41) slightly moves in the width direction E1 or E2 due to the meandering (provided that the swing supporting member 87 is in a vertical neutral state without swinging), FIGS. As shown in FIG. 11, the contact arm 8 of the swing contact member 84 follows the movement of the belt.
2 swings around the first support shaft 81 in the arrow J direction or the arrow K direction, and in conjunction with this swing, the detected arm unit 83 similarly moves around the first support shaft 81 in the arrow J direction or the arrow K direction. And is displaced (a state shown by a dotted line 83a in FIG. 12).
Then, the displacement of the detected arm 83 at this time is measured by the sensor 88.

When the belt 21 (41) moves significantly in the width direction E1 or E2 due to the meandering, the swing contact member 84 first strikes one of the stop members 85a and 85b, and the swing is caused. After stopping (FIGS. 10a and 11a), the swing support member 87 stops the second support shaft 86 and swings in the arrow J direction or the arrow K direction while the swing contact member 84 is held in that state. Swing support member 87
As a result, the position of the detected arm portion 83 is further displaced substantially in the direction of the arrow J or the direction of the arrow K (a state shown by a dotted line 83b in FIG. 12). Then, the final displacement of the detected arm 83 at this time is measured by the sensor 88.

FIG. 12 shows the swing angle (θ) of the swing contact member 84 and the swing support member 87 at this time and the detected portion 83.
2 shows the relationship between the displacement amount (W, S) and the relationship between each displacement amount and a sensor 88 that measures each displacement amount. FIG. 13 shows the relationship between the swing state of the swing contact member 84 and the swing support member 87 and the sensor output value with respect to each belt meandering amount.

From FIG. 12 and FIG. 13, the first support shaft 8
The swing contact member 84 that swings at 1 is fixed to the first support shaft 81 and is supported by the swing support member 87 that swings at the second support shaft 86, so that the swing contact member 84 becomes the first support shaft 81. And the second support shaft 86 is configured to swing in two stages around different support shafts, so that the amount of displacement of the swing contact member 84 with respect to the swing angle is the same as in the first embodiment. The amount of displacement increases by one step (by the amount of displacement S) as compared with the amount of displacement when swinging by one support shaft 60, and the detection range of the belt position is widened. That is, the swing contact member 8
4 oscillates on the first support shaft 81 and is displaced by the amount of displacement (± W), and then the oscillating support member 8 supporting the oscillating contact member 84
7 is further displaced by the displacement amount (± S) on the second support shaft 86. Thereby, even when the belt is greatly fluctuated and the swing contact member 84 swings greatly,
By swinging the two support shafts 81 and 86 in two stages, the displacement amount at that time can be measured.

When the movement of the belt 21 (41) in the width direction is within a range close to the prescribed position N (the swing contact member 7).
5 is in the range of 0 to ± θ), the displacement amount of the detected arm portion 83 due to the swing of the swing contact member 84 on the first support shaft 81 having a large displacement amount with respect to the swing angle is The belt 21 is measured by the sensor 88.
The position (small fluctuation) of (41) can be accurately detected. Thereby, the belt displacement means 52 can be operated based on the highly accurate detection information of the belt position, so that the meandering of the belt occurring near the prescribed displacement position N can be more accurately suppressed.

On the other hand, when the movement of the belt 21 (41) in the width direction is largely separated from the vicinity of the prescribed position N (the swing angle of the swing contact member 75 is + θ to + 2θ or -θ to -2θ).
), The amount of displacement of the detected arm 83 due to the swing of the swing support member 87 on the second support shaft 86 having a small amount of displacement for the large movement is detected by the sensor 88.
The belt 21 fluctuates greatly because it is measured by
Even the position (41) can be detected reliably. As a result, even if there is a significant change in the belt position, the change is detected, so that the belt can be surely returned to the specified position N by the operation of the belt displacement means 52.

Therefore, the belt position detecting means 80
The same effect as in the first embodiment described above can also be obtained with the belt meandering suppressing device 50 using.

[0060]

As described above, according to the belt meandering suppressing device of the present invention, displacement in the belt width direction due to belt meandering or the like can be detected in a wider range. More extensive deterrence. In addition, while the belt position can be detected with higher accuracy for the belt displacement within a range close to the specified position, the belt position can be detected for the belt displacement within a range far from the specified position. Although the detection accuracy is low, a wider range of displacement can be detected, thereby making it possible to detect the belt position and suppress meandering very efficiently.

[Brief description of the drawings]

FIG. 1 shows an example of an image forming apparatus to which the present invention can be applied. FIG. 1A is a schematic configuration diagram of an example of an image forming apparatus using an intermediate transfer belt mechanism, and FIG. FIG. 1 is a schematic configuration diagram of an example of an image forming apparatus that uses a printer.

FIG. 2 is a schematic perspective view illustrating a configuration of a belt mechanism and a belt meandering suppressing device according to the first embodiment.

FIG. 3 is a schematic diagram illustrating a belt position detecting unit according to the first embodiment.

4 is a diagram showing a relationship between a swing angle of a swing contact member and a displacement amount of each position of a detected arm in the belt position detecting means of FIG. 3, and a first sensor for measuring each displacement amount and each displacement amount; FIG. 4 is an explanatory diagram showing a relationship between a second sensor and a second sensor.

FIG. 5 is a correlation diagram showing a relationship between a swing state of a swing contact member and a sensor output value with respect to each belt meandering amount in the belt position detecting unit of FIG. 3;

FIG. 6 is a schematic diagram illustrating a belt position detecting unit according to the second embodiment.

FIG. 7 shows a relationship between a swing angle of a swing contact member in the belt position detecting means of FIG. 6 and a displacement amount of each detected curved surface in a detected portion, and a sensor for measuring the respective displacement amounts and the respective displacement amounts. FIG.

8 is a correlation diagram showing a relationship between a swing state of a swing abutment member and a sensor output value with respect to each belt meander amount in the belt position detection unit of FIG. 6;

FIG. 9 is a schematic diagram illustrating a belt position detecting unit according to the third embodiment.

FIG. 10 is an explanatory view showing an operation state of the swing contact member and the swing support member in the belt position detecting means of FIG. 9 (when the belt moves in one direction).

FIG. 11 is an explanatory view showing an operation state of the swing contact member and the swing support member in the belt position detecting means of FIG. 9 (when the belt moves in the other direction).

12 shows a relationship between the swing angle of the swing contact member and the swing support member in the belt position detecting means of FIG. 9 and the displacement amount of the detected arm portion, and the respective displacement amounts and a sensor for measuring the respective displacement amounts. FIG.

13 is a correlation diagram showing a relationship between a sensor output value and a swing state of a swing contact member and a swing support member with respect to each belt meandering amount in the belt position detecting unit of FIG. 9;

FIG. 14 is a schematic configuration diagram illustrating a typical example of a belt position detecting unit in the related art.

[Explanation of symbols]

21: intermediate transfer belt (belt), 22 to 25: plural rolls, 41: sheet transport belt (belt), 42 to 4
5, a plurality of rolls, 50, a belt meandering suppressing device, 51,
70, 80: Belt position detecting means, 52: Belt displacement means, 60, 71: Support shaft, 61, 72, 82 ... Contact arm part, 62, 83 ... Detected arm part, 63, 75, 84 ...
Swing contact member, 64, 65... A plurality of sensors, 73 a, 7
3b, 73c: detected curved surface, 74: detected portion, 76, 8
Reference numeral 8: sensor, 81: first support shaft, 85a, 85b: stop member, 86: second support shaft, 87: swing support member, B, C: circumferential direction of the belt, E1, E2: width direction of the belt, G1 ,
G2: Positions with different distances from the support shaft.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification FI FI Theme Court ゛ (Reference) G03G 15/16 G03G 15/16 3F048 // B65G 15/64 B65G 15/64 3F049 (72) Inventor Mitsuaki Kuroda 2274 Hongo, Ebina-shi, Kanagawa Prefecture, inside Fuji Xerox Co., Ltd. Inside Fuji Xerox Co., Ltd. (72) Inventor Kazuo Takano 2274 Hongo, Ebina-shi, Kanagawa Prefecture, Inside Fuji Xerox Co., Ltd. (72) Inventor Norio Hokari 2274 Hongo, Ebina-shi, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72 Inventor Takashi Hoshino 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Zero (72) Inventor Susumu Yamashina 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Kozo Tagawa 2274 Hongo, Ebina City, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Invention Person Satoshi Nishikawa 2274 Hongo, Ebina City, Kanagawa Prefecture, within Fuji Xerox Co., Ltd. (72) Inventor Yoshihiko Mitamura 2274 Hongo, Ebina City, Kanagawa Prefecture, F X-Term Co., Ltd. DD20 GG01 GG04 GG07 GG21 GG62 GG63 HH04 HH09 HH30 JJ13 MM00 2H027 DA22 DE02 DE07 ED01 2H032 BA09 BA18 CA02 2H035 CB06 CF02 CG01 3F023 AA05 BA02 BB01 BB09 BC01 CA02 GA01 3A04 BA02 A LA05 LA07 LB01

Claims (3)

[Claims] 1. A belt position detecting means for detecting a position in a width direction orthogonal to a circling direction of a belt stretched around a plurality of rolls, and based on position information detected by the belt position detecting means. A belt meandering restraint device comprising: belt displacement means for displacing the belt in the width direction and returning the belt to a predetermined position. The belt position detection means contacts the side end of the belt and moves in the width direction of the belt. A swinging contact member having a contact arm that swings about a support shaft following the above, and a detected arm that swings about the support shaft in conjunction with the swing of the contact arm; A belt meandering suppression device, comprising: a plurality of sensors for individually measuring displacements of a plurality of positions at different distances from the support shaft in a detected arm portion of a swing contact member. 2. A contact arm which abuts on a side end of the belt and swings around a support shaft following the movement of the belt in the width direction, instead of the belt position detecting means according to claim 1. And a sensed part formed with a plurality of types of sensed curved surfaces having different amounts of displacement when swinging about the support shaft and passing through the same position due to the swing in conjunction with the swing of the contact arm part. Using a belt position detecting means comprising: a rocking contact member having: and a sensor for measuring a displacement of each of different detected curved surfaces in a detected portion of the rocking contact member. apparatus. 3. The belt position detecting means according to claim 1, wherein said belt is in contact with a side end of said belt and swings about a first support shaft following movement of said belt in a width direction. A swing contact member having a contact arm portion, a detected arm portion swinging about the first support shaft in conjunction with the swing of the contact arm portion, and a first support shaft of the swing contact member. A pair of left and right stop members are provided, which are fixed and stop the swing of the contact member at the regulated position so as to regulate the swing range of the contact member that swings on the first support shaft, and A swing support member that swings around a second support shaft parallel to the first support shaft at a position different from the first support shaft while supporting the swing contact member, and supported on the swing support member. A sensor for measuring the displacement of the detected arm of the swing contact member. A belt meandering preventing device using the belt position detecting means thus configured.