JP2000344381A - Sheet conveying device and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet conveying device and an image forming device capable of identifying accurately the exchange time of a feeding roller, and excellent in reliability. SOLUTION: A rubber part 20 of a retard roller 3b comprises a surface layer 20a processed polishing grains and a core layer 20c in its inside, and the surface layer 20a and the core layer 20c are different in color. When the retard roller 3b is worn down by griding through each other with a paper sheet P, a user can understand the life of the retard roller 3b by watching the retard roller 3b from a monitoring part, and can adequately identify the exchange time of the retard roller 3b only by watching and confirming from the outside of the device because the core layer 20c appears to change color on a surfaces of the rubber part 20.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet conveying apparatus provided with a conveying roller for conveying a sheet such as a sheet feeding unit for sending out a sheet fed from a sheet storing section such as a sheet feeding tray to an image forming section. For example, copiers, printing machines,
It is applied to an image forming apparatus such as a printer.

[0002]

2. Description of the Related Art Conventionally, in a sheet feeding unit as a sheet conveying device incorporated in an image forming apparatus such as a copying machine, a sheet as a sheet fed by a pickup roller from a sheet feeding tray is sent to a predetermined conveying path. Some have a paper feed roller as a pair of transport rollers.

Usually, a high friction material such as rubber is used on the outer peripheral portion of the paper feed roller to prevent slippage with the paper, and for example, a rubber portion is provided.

[0004] This kind of paper feed roller wears due to friction with the paper at the time of paper feed, and when this becomes remarkable, paper jam is likely to occur. Therefore, when the feed roller reaches a certain wear limit level, it is necessary to replace the feed roller.

On the other hand, in the conventional paper feeding unit, when the paper feeding roller is incorporated in the main body of the image forming apparatus, the paper feeding roller is shielded by the unit frame (sheet metal frame), and is hidden behind a position invisible from the outside of the apparatus. I will. Therefore, in order to judge when to replace the paper feed roller, it is necessary to perform a troublesome operation such as removing a component using a tool.

Therefore, as a means for identifying the timing of replacing the paper feed roller without troublesome work, the number of sheets processed by the image forming apparatus having been fed is managed by a counter, and the count value is used to determine the timing of replacing the paper feed roller. It was considered to be used for standards.

[0007]

However, in the case of the above-described prior art, the following problems have occurred.

In an image forming apparatus provided with a plurality of paper feed trays corresponding to each paper size, the number of paper feeds from each paper feed tray varies, and the number of paper feeds varies depending on the paper quality of the paper used. There is a difference in the amount of wear of the paper roller.

For this reason, when the paper feed roller is replaced based on the count value of the number of processed sheets as described above, even the paper feed roller which does not need to be replaced may be replaced.
Conversely, the paper feed roller may be replaced after a paper jam has occurred much later than the time for replacement.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide a highly reliable sheet conveying apparatus capable of accurately identifying the timing of replacing a conveying roller. An object of the present invention is to provide an image forming apparatus.

[0011]

In order to achieve the above object, a sheet conveying apparatus according to the present invention has a rubber portion which contacts a sheet on an outer surface and a support portion which supports the rubber portion from the inside. In a sheet conveying apparatus provided with a conveying roller, the rubber portion is provided in multiple layers with different colors for each layer toward the inside, and the color of the outer surface of the rubber portion is changed according to the wear amount of the rubber portion. It is characterized by making it.

Therefore, since the outer surface of the rubber portion of the transport roller changes color due to wear, the outer surface changes to a predetermined color when the transport roller is replaced. Time can be accurately identified.

It is preferable that a monitoring means is provided for making the outer surface of the rubber portion visible from outside the apparatus. Thus, the outer surface of the rubber portion of the transport roller can be visually monitored from outside the apparatus.

In the case where the rubber portion is installed so as to be mounted on the support portion upside down, and the rubber portion is mounted upside down,
It is preferable that the transporting roller abuts the inner surface of the rubber portion that is turned over on the sheet.

[0015] Thus, the outer surface and the inner surface of the rubber portion can be brought into contact with the sheet, and the life of the rubber portion can be reduced by about two.
Can be doubled.

It is preferable that the rubber portion is provided in three layers toward the inside, and of the three layers, the middle second layer is higher in hardness than the outside first layer and the inside third layer.

Thus, the intermediate second layer is formed on the outer first layer.
Even when the layer is worn and the rubber portion is not turned upside down, the hardness is high and it is hard to wear, so that it is possible to prevent the abrasion from progressing and exposing the inner third layer to the surface.

It is preferable that a rubber width of the rubber portion is shorter than an outer diameter of the rubber portion.

Thus, the rubber portion can be easily turned over.

[0020] It is preferable that the outer surface and the inner surface of the rubber portion are provided with polishing lines.

Thus, the outer surface and the inner surface of the rubber portion can abut on the sheet in the same manner.

A fitting portion for fitting with the support portion is provided at one end of the rubber portion in the rubber width direction, and the outer surface and the inner surface of the rubber portion are polished in opposite directions. Is preferably provided.

Thus, since there is a fitting portion provided at one end in the rubber width direction, the mounting direction of the rubber portion to the support portion is determined. It can be in the same direction.

It is preferable that a wear detecting means for detecting a wear amount of the rubber portion is provided.

Thus, even when the user does not visually check the wear of the rubber portion of the transport roller, the wear amount of the rubber portion can be detected.

It is preferable that the rubber portions are provided so as to have different layer thicknesses in the rubber width direction, and a plurality of the wear detecting means are provided in portions of the rubber portion having different layer thicknesses in the rubber width direction.

Thus, the wear amount of the rubber portion when the plurality of wear detecting means detects the next layer is different, so that the wear amount of the rubber portion can be detected stepwise by the plurality of wear detecting means.

It is preferable that a notification unit is provided for notifying a user that the predetermined wear amount of the rubber portion has been detected by the wear detection unit.

Thus, even when the user does not visually check the wear of the rubber portion of the transport roller, the user can know that the rubber portion has worn by a predetermined amount.

It is preferable that the notifying means displays a message on a display unit to notify a user.

It is preferable that the notifying unit generates a sound from a sound generating unit and notifies the user.

An image forming apparatus according to the present invention is characterized by including the above-mentioned sheet conveying apparatus and image forming means for forming an image on a sheet.

[0033]

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the dimensions of the components described in this embodiment,
The materials, shapes, relative arrangements, and the like are not intended to limit the scope of the present invention only to them unless otherwise specified.

(First Embodiment) Hereinafter, a first embodiment applied to a sheet feeding unit mounted on a copying machine and feeding a sheet as a sheet to an image forming section will be described with reference to the drawings. This will be described in detail.

The present invention is not limited to a sheet feeding unit mounted on a copying machine, but is, for example, a sheet conveying device mounted on an image forming apparatus such as a copying machine, a printing machine, or a printer and provided with a conveying roller. It is generally applicable.

Here, the description of the image forming section including the image forming means for forming an image on a sheet is omitted,
For example, it is configured using a known image forming unit such as an electrophotographic system or an inkjet system.

FIG. 1 is a view for explaining a first embodiment of a sheet feeding unit according to the present invention. FIG. 1 (a) is a perspective view thereof, and FIG. 1 (b) is a sectional view of a main part thereof. is there.

In the paper feed unit 1 shown in FIG. 1, a paper feed roller 3 as a pair of transport rollers is provided inside a unit frame 2. Each of the pair of paper feed rollers 3 includes a feed roller 3a on the rotation drive side and a retard roller 3b pressed against the feed roller 3a by a spring pressure or the like.

One of the feed rollers 3a has a function of feeding out a sheet P as a sheet by its rotation, and the other retard roller 3b has a function of preventing double feeding or the like (sheet separating function).

Feed roller 3a and retard roller 3
A plurality of b's are attached to separate rotating shafts (one of the intermediate support members) at predetermined intervals in the axial direction, so that any paper P within a specified size can be handled. ing.

In addition, inside the unit frame 2,
A pickup roller 6 for feeding out the sheets P stacked on the sheet supply table 5 of the sheet supply tray 4 serving as a sheet storage unit is provided. The paper P stacked on the paper feed tray 4 is pressed against the pickup roller 6 by urging means (not shown) provided on the paper feed tray 4 side.

At the time of paper feeding, the pickup roller 6
Is driven in order from the uppermost sheet P abutting on the pickup roller 6, and the fed sheet P is delivered to the pair of sheet feed rollers 3.

On the other hand, on one end side of the unit frame 2,
A mounting piece 7 is provided as a fixing portion to the main body of the copying machine. A motor serving as a drive source of the feed roller 3a, a driving force transmission system and a wiring system associated therewith are provided on the other end of the unit frame 2. Is provided. As shown in FIG. 2, the paper feeding unit 1
The paper P is incorporated in the main body 9 of the copier in accordance with the paper storage position of the copier, that is, the storage position of the paper P when the paper feed tray 4 is set in the copier.

An opening / closing cover 10 for removing jams and for maintenance is attached to the right hand side of the main body 9 as viewed from the user side. Paper feed unit 1 in a one-to-one relationship
Is incorporated.

Then, the paper P in the paper feed tray 4 is transferred to a pair of paper feed rollers 3 of the corresponding paper feed unit 1.

Here, when two sheets of paper P are fed out simultaneously from the pickup roller 6 to the pair of paper feed rollers 3, the first (upper) sheet P is fed to the feed roller 3a. The second sheet (the lower side) of the sheet P is in contact with the retard roller 3b and is sandwiched between the pair of sheet feeding rollers 3.

At this time, a predetermined rotational load is applied to the retard roller 3b, and this rotational load, together with the frictional force between the retard roller 3b and the sheet P, is a force that prevents the advance of the second sheet P. Acts as.

At this time, on the feed roller 3a side, the first sheet P is reliably advanced by the rotation thereof.
Almost no wear.

However, since the retard roller 3b is rubbed with the second or subsequent sheet P, the retard roller 3b gradually wears as the sheet feeding operation is repeated, and the amount of wear is more than a certain level. Becomes a cause of paper jam and the like.

What greatly affects the life of the retard roller 3b is the surface condition of the retard roller 3b due to wear.

Normally, the surface of the retard roller 3b is
As shown in the figure, the polishing line is provided in the direction of the regular line with respect to the transport direction of the sheet P. This polished eye is 0.8m thick
However, when the polishing line is eliminated, the conveying force is reduced.

Further, if sheet feeding is continued in this state,
The outer diameter of the retard roller 3b is unevenly worn, so that the pressure is applied non-uniformly, and the average value of the pressing force is weakened. As a result, when the wear amount exceeds a certain level, a paper feeding failure occurs.

Therefore, in the present embodiment, an example will be described in which the color change of the surface layer is detected with a wear detection target of the pair of paper feed rollers 3, particularly the retard roller 3b.

First, with respect to the sheet feeding unit 1, a monitoring unit 12 is formed on the unit frame 2 as monitoring means so that the wear state of the retard roller 3b can be visually checked. As shown in FIG. 2, the monitoring unit 12 is provided on the front surface of the unit frame 2 exposed to the outside when the opening / closing cover 10 of the copying machine is opened, with a part thereof being opened.

The position of the monitoring unit 12 on the front of the unit frame 2 is, as shown in FIGS.
When opening 0 and observing the inside of the frame from the monitoring unit 12,
The retard roller 3b is set at a position where the retard roller 3b can be seen from outside the copying machine.

Incidentally, the front surface of the unit frame 2 on which the monitoring unit 12 is formed serves as a guide surface of a common paper conveyance path for the paper P fed from each paper feed tray 4. As shown in FIG. 3, the peripheral portion is squeezed inward, or a slight step is provided (not shown) to catch the paper P on the paper transport path side indicated by an arrow in FIG. 3. Care must be taken not to leave any parts.

Further, by inserting a transparent member (for example, polycarbonate resin) into the opening / closing cover 10, the retard roller 3b can be viewed from outside the machine without opening / closing the opening / closing cover 10.

Next, the structure of the retard roller 3b disposed in the sheet feeding unit 1 will be described. In the present embodiment, a case will be described in which the rubber portion 20 of the retard roller 3b has two layers inward.

Normally, the retard roller 3b is
And a core part 21 as a support part.

The rubber portion 20 of the retard roller 3b
As shown in FIG. 5, the surface layer 20a includes a surface layer 20a on which polishing is processed and an inner core layer 20c. The surface layer 20a and the core layer 20c have different colors.

In the process in which the retard roller 3b wears due to the rubbing with the paper P, the wear reaches a predetermined amount of wear. Then, the core layer 20c appears and the color of the surface of the rubber portion 20 changes, so that the user
By visually observing the retard roller 3b from 2, the life of the retard roller 3b can be known.

As a result, the replacement time of the retard roller 3b can be accurately identified only by visual confirmation from the outside of the apparatus without performing troublesome work such as removal of parts as in the related art.

In the present embodiment, the paper feed roller 3 has been described as an example.
The present invention can be applied.

In addition to providing two intermediate layers of different colors between the surface layer 20a and the core layer 20c in addition to the two layers of the surface layer 20a and the core layer 20c, the life of the roller is reduced at the stage of abrasion. The user may be alerted.

(Second Embodiment) By the way, in an inexpensive printer, the number of sheets passed is not so large as in a printing machine, so that the opportunity to replace the retard roller 3b is at most once. Therefore, it is very troublesome to order a new retard roller 3b from a manufacturer and replace it.

Therefore, in the present embodiment, a configuration is proposed in which the rubber portion 20 of the roller whose life has expired can be turned over and used again. Here, only the retard roller 3b, which is a characteristic part of the present embodiment, will be described, and other configurations are the same as those of the first embodiment.

In the present embodiment, as shown in FIG. 6, the inner diameter φD1 of the rubber portion 20 is larger than the outer diameter φD2 of the core portion 21 (φD1> φD2). The rubber part 20 is turned upside down so that it can be used again.

The rubber width T, which is the contact width of the rubber portion 20 in the axial direction, is shorter than the outer diameter φD3 of the rubber portion 20 (T> φD3). This makes it possible to easily turn the rubber portion 20 upside down.

Further, the convex portion 23 and the rubber portion 2
A concave portion (or cutout portion) 24 as a fitting portion that fits with the convex portion 23 is provided at one end of the rubber width 0.

The protrusions 23 and the recesses 24 are formed by the rubber portions 20.
And the metal core 21 may be provided in reverse, and the shape is not limited to these as long as they can be fitted.

The rubber portion 20 has a surface layer 2 as an outer first layer.
0a, a core layer 20c as an intermediate second layer, and an inner third layer.
It has three layers including a surface layer 20b as a layer.

The hardness of the second core layer 20c is higher than the hardness of the first and third surface layers 20a and 20b. Thereby, the second core layer 20c has a high hardness and is hard to be worn even when the replacement of the rubber part 20 is forgotten, so that the second core layer 20c is prevented from being worn and reaching the surface layer on the opposite side. Further, the rubber portion 20 has an outer surface that is fitted to the rubber portion 20 and an inner surface that is fitted with the core metal portion 21, that is, the surface layer 20a,
Polished lines are formed on each surface of 20b.

Normally, the polishing points in contact with the sheet are first in the sheet conveying direction, as shown in FIG. 5 in the first embodiment.

For this reason, in the present embodiment, the core 21
In the rubber portion 20, the one end of the rubber width at which the concave portion 23 is provided is determined as the mounting direction.
The polishing surface is formed in the opposite direction to the polishing surface on the outer surface (the surface of the surface layer 20a), so that even if the rubber portion 20 is turned over, the polishing surface contacts the paper in order.

Here, a method of manufacturing the three-layer rubber portion 20 used in the present embodiment will be described. First, the third layer (the surface layer 20b) is manufactured using a mold, and the second layer (the core layer 20b) is manufactured.
c) The first layer (surface layer 20a) is formed by applying a semi-liquid rubber layer, and then the surface of the first layer is polished with a cylindrical grindstone to form polished lines. The third layer can be polished upside down and polished in the same manner as the first layer, or as shown in FIG.
Polishing is performed using the polishing roller 28 from the inner diameter side.

With the above configuration, the protrusions 23 of the cored bar 21 are formed.
And the recess 24 of the rubber portion 20 are merely fitted, so that the rubber portion 20 can be easily removed.
When the rubber portion 20 is turned over, the concave portion 2 of the rubber portion 20 is formed.
4, the mounting direction of the rubber portion 20 is fixed, and the direction of the polished eye is not reversed.

On the other hand, even if the fitting between the rubber portion 20 and the core metal portion 21 is performed with a clearance fit, since the concave portion 24 of the rubber portion 20 is fitted to the convex portion 23 of the core metal portion 21, Does not spin idle.

Therefore, since the rubber portion 20 of the retard roller 3b is used upside down, the life per one roller can be almost doubled.

Further, the replacement of the retard roller 3b is only an operation of turning over the rubber portion 20, and there is no trouble of obtaining a new rubber portion 20 from a manufacturer.

(Third Embodiment) Next, a configuration in which wear detecting means is provided for the retard roller 3b will be described. As shown in FIG. 8, the paper jam is caused by the retard roller 3.
This is a configuration for more surely informing the user whether or not it has occurred due to the wear of b.

Here, the retard roller 3b has the same three-layer rubber portion 20 as in the second embodiment and can be used upside down. Other configurations are the same as those of the first and second embodiments, and the same reference numerals are given and the description is omitted.

As shown in FIG. 8, a non-contact wear detecting means 25 is provided for the retard roller 3b.

The wear detecting means is a non-contact type wear detecting means 2
5 includes, for example, a gap sensor and a reflection sensor.

When a gap sensor is used as the non-contact type wear detecting means 25, the replacement time is identified by detecting the wear amount of the retard roller 3b based on the gap amount.

On the other hand, the case where a reflection type sensor is used as the non-contact wear detecting means 25 will be described below.

Generally, a reflection type sensor has a white background color (for example,
White, gray, and yellow) and the color of a black background (eg, black, blue, and green) have characteristics in which the light reception output varies.

By utilizing this characteristic, the retard roller 3b
The first and third layers of the rubber portion 20 are provided on a white background color (eg, white, gray, yellow) that is easy to reflect, and the second layer is a black background color (eg, black, blue, green) that is difficult to reflect. ), When the first layer is worn, the second layer is exposed, so that the output value of the reflection sensor is changed.

Thus, in the reflection type sensor, when the first layer is worn and the output value exceeds a certain level, the replacement time is identified.

The above-mentioned non-contact type wear detecting means 25
Thus, there is an advantage that the life of the retard roller 3b is not shortened.

Further, in the non-contact type wear detecting means 25,
Although the contact portion may cause the retard roller 3b to wear, the contact roller may be replaced with a contact-type wear detecting unit. As a contact-type abrasion detecting means, for example, as shown in FIG. 9, there is provided a lever 26 which is always in contact with the retard roller 3b, and a photo sensor 27 whose optical path is blocked by the lever 26.

In the above-described configuration of the lever 26 and the photosensor 27, when the amount of wear of the retard roller 3b increases,
The lever 26 tilts to contact the retard roller 3b, and cannot interrupt the optical path of the photosensor 27, so that the replacement time is identified.

When the wear of the retard roller 3b is detected by using the above wear detecting means, the retard roller 3b
Even if the amount of wear of the
It is possible to know the time when a predetermined amount of wear has occurred, and it is possible to more reliably notify the user whether or not the paper jam has occurred due to the wear of the retard roller 3b.

Note that the retard roller 3b may have the rubber portion 20 that is used upside down and is not used, which is used in the first embodiment.

(Fourth Embodiment) Next, the retard roller 3b is detected by the wear detecting means used in the third embodiment.
A description will be given of an embodiment in which when wear is detected, a message such as "feed roller replacement time" is displayed on a liquid crystal operation unit as a display unit in the copying machine, and a notifying means is provided to inform the user of the replacement time. Here, an example in which a gap sensor is used as the wear detecting means will be described.

FIG. 10 is a flowchart for displaying a message on the liquid crystal. The flowchart of FIG. 10 shows an example in which the exchange message is displayed immediately after the copy button is pressed so that the user can know the exchange time during the operation.

First, the user presses a copy button (step S1). A signal that the copy button has been pressed is transmitted to the gap sensor, and the gap sensor emits light (step S2).

Then, the output value a of the light receiving output is read (step S3), and the wear amount of the retard roller 3b is detected.

The detection of the wear amount is performed by comparing the read output value a with the discrimination value b (step S4), and the output value a> the discrimination value b.
, A signal is input to the liquid crystal operation unit (step S
5) A message "It is time to replace the paper feed roller" is displayed on the liquid crystal operation unit (step S6). At this time, a beep sound may be generated by inputting a signal to a beep unit serving as a sound generating unit.

After the detection of the wear amount is completed, a copying operation is performed (step S7). In step S4, output value a>
Even when the identification value b has not been reached, step S7 is performed as it is.
Then, the copying operation is performed. As described above, by displaying a message on the liquid crystal operation unit immediately after pressing the copy button, it is possible to reliably notify the user of the wear of the retard roller 3b.

(Fifth Embodiment) Next, a case where not only the life detection but also the remaining life detection are performed by the wear detecting means used in the fourth embodiment will be described.

If it is known in advance that the life expectancy of the retard roller 3b is short before the end of the life of the retard roller 3b, it is possible to take measures such as changing the sheet feeding position.

Therefore, as shown in FIG. 11, the thickness of the core layer 20c of the rubber portion 20 is changed in the rubber width direction. Then, sensors 30 and 31 as wear detecting means are disposed at two places where the layer thicknesses are different.

In FIG. 11A, the rubber portion 2 at the center of the rubber width is shown.
The core layer 20c of FIG.
In the figure, the core layer 20c of the rubber portion 20 at the center of the rubber width is provided thin.

Further, a reflection type sensor is used for the sensors 30 and 31 so that a change in the color of the rubber portion 20 can be read.

With the above configuration, as the rubber portion 20 wears, the color of the surface layer changes first as the thinner surface layer wears, and is detected by one of the sensors 30 and 31. An indication that the life expectancy is approaching is displayed on the liquid crystal operation unit.

When the wear further proceeds and the remaining sensor detects the wear, an exchange message is displayed on the liquid crystal operation unit.

As described above, if a different message is displayed according to the amount of wear, the user can know the life of the retard roller 3b in advance, which is convenient for taking measures.

[0108]

As described above, according to the present invention, the color of the outer surface of the rubber portion changes in accordance with the wear of the transport roller. In addition, it is possible to accurately determine the time for replacing the transport roller.

Further, by using the transport roller even if the rubber portion is turned over, the life per rubber portion can be almost doubled.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a sheet feeding unit.

FIG. 2 is a perspective view illustrating a state in which a sheet feeding unit is assembled into an apparatus main body.

FIG. 3 is an enlarged view of a main part for explaining details of a monitoring unit.

FIG. 4 is a diagram illustrating a position of a monitoring unit.

FIG. 5 is a diagram illustrating a retard roller according to the first embodiment.

FIG. 6 is a diagram illustrating a retard roller according to a second embodiment.

FIG. 7 is a diagram illustrating a method of polishing a third layer.

FIG. 8 is a diagram illustrating a wear detecting unit according to a third embodiment.

FIG. 9 is a view for explaining a contact-type wear detecting means.

FIG. 10 is a flowchart of wear detection according to a fourth embodiment.

FIG. 11 is a diagram illustrating a retard roller and a wear detecting unit according to a fifth embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper feed unit 2 Unit frame 3 Paper feed roller 3a Feed roller 3b Retard roller 4 Paper feed tray 9 Main body 12 Monitoring part 20 Rubber part 20a First layer 20b Third layer 20c Second layer 21 Core metal part 23 Convex part 24 Recess 25 Wear detection means (non-contact type) 26 Lever 27 Photosensor 28 Polishing roller

Claims (13)

[Claims] 1. A sheet transporting apparatus comprising a transport roller having a rubber portion that contacts a sheet on an outer surface and a support portion that supports the rubber portion from the inside. A sheet conveying device comprising: a plurality of layers having different colors, wherein a color of an outer surface of the rubber portion is changed according to an amount of wear of the rubber portion. 2. The apparatus according to claim 1, further comprising monitoring means for making the outer surface of said rubber portion visible from outside the apparatus.
3. The sheet conveying device according to 1. 3. The method according to claim 1, wherein the rubber portion is mounted on the support portion so that the rubber portion can be mounted on the support portion. The sheet conveying device according to claim 1, wherein the sheet conveying device is in contact with the sheet conveying device. 4. The method according to claim 1, wherein the rubber portion is provided in three layers inward, and of the three layers, the middle second layer has a higher hardness than the outer first layer and the inner third layer. The sheet conveying device according to claim 3, wherein 5. The sheet conveying device according to claim 3, wherein a rubber width of the rubber portion is shorter than an outer diameter of the rubber portion. 6. The sheet conveying apparatus according to claim 3, wherein an outer surface and an inner surface of the rubber portion are provided with polishing lines. 7. A fitting portion for fitting with the support portion is provided at one end of the rubber portion in the rubber width direction, and the outer surface and the inner surface of the rubber portion are polished in opposite directions. The sheet conveying device according to claim 6, wherein the sheet conveying device is provided at a polishing eye. 8. The sheet conveying apparatus according to claim 1, further comprising a wear detecting means for detecting a wear amount of said rubber portion. 9. A method according to claim 1, wherein said rubber portions are provided with different layer thicknesses in the rubber width direction, and a plurality of said wear detecting means are provided in portions of said rubber portions having different layer thicknesses in the rubber width direction. The sheet conveying device according to claim 8, wherein 10. The sheet conveying apparatus according to claim 8, further comprising a notifying means for notifying a user that a predetermined amount of wear of the rubber portion has been detected by the wear detecting means. 11. The apparatus according to claim 10, wherein said notifying means notifies a user by displaying a message on a display unit.
3. The sheet conveying device according to 1. 12. The sheet conveying apparatus according to claim 10, wherein said notifying means notifies a user by generating a sound from a sound generating unit. 13. An image forming apparatus comprising: the sheet conveying device according to claim 1; and an image forming unit that forms an image on a sheet.