JPH02138051A - Sheet material conveying device - Google Patents

Abstract

PURPOSE:To prevent a skew of a sheet material by making the conveying speed of the sheet material via conveying rollers different between the portion provided with a restricting member and the portion not provided with it in response to the positional relation between the conveying rollers and the restricting member in the conveyance direction of the sheet material to thrust the sheet material to the restricting member. CONSTITUTION:The conveying speed difference of a sheet material between the portion provided with a restricting member 9 and the portion not provided with it is determined in response to the positional relation between conveying rollers 10 and the restricting member 9 of the sheet material in the conveyance direction of the sheet material. The sheet material S is conveyed while being thrust to the restricting member 9. As a result, even if the conveying rollers 10 are one-sidedly abraded, the sheet material S is not skewed immediately, and a skew of the sheet material S can be prevented for a long period.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a sheet material conveying device applied to an image forming apparatus such as a copying machine, and in particular to a sheet material conveying device that uses a plurality or long rollers to convey a sheet material. The present invention relates to a sheet material conveying device that performs.

(Prior Art) Conventionally, as this type of device, one shown in FIG. 5, for example, is known. In this device, three conveyor rollers 101, 102, 103 made of rubber with the same diameter are attached to a drive shaft 100.
The sheet material So is rotated by a motor (not shown).
is conveyed in the direction of the arrow Ao force. and,
The sheet material S is on the upstream side in the sheet material conveyance direction.

A lateral resist plate 104 is provided on one side of the conveyance path (on the left side in the figure) to prevent skewing. The sheet material SO whose displacement in the width direction is regulated by the lateral registration plate 104 is guided as it is to the registration roller 105 by the rotation of the conveyance rollers 101 to 103.

(Problem to be Solved by the Invention) By the way, in such a conventional example, when the rubber conveyance rollers 101 to 103 are used for a long period of time, the outer diameters of the rollers become unbalanced due to wear.
-103, there may be a difference in the conveyance speed of the sheet material So.

For example, when comparing the conveyance rollers 101 and 103 on both sides, if the conveyance roller 103 on the side opposite to the horizontal registration plate 104 has more wear, then the conveyance roller on the side of the horizontal registration plate 104 relatively The outer diameter of the roller 101 becomes larger, and the conveyance speed of the roller 101 becomes larger. Therefore, the sheet material So receives a force in the direction of arrow P1 at the leading end, and receives a force in the direction of arrow P2 at the rear end. However, in this case, since the sheet material So is regulated by the lateral resist plate 104, it does not skew on the upstream side of the sheet material conveyance direction of the conveyance rollers 101 to 103, and furthermore, the rear end of the sheet material So is regulated by the lateral resist plate 104. 1
Since the front end of the sheet material So is pinched by the registration rollers 105 before leaving the sheet material So, skewing of the sheet material So does not occur even on the downstream side in the sheet material conveyance direction.

On the other hand, in the opposite case, that is, when the conveyance roller 101 on the side of the horizontal registration plate 104 is worn more than the conveyance roller 103 on the opposite side, the sheet material S
However, in this case, the sheet material S is on the right side in the conveyance direction of the sheet material So.

Since no means is provided to prevent the sheet material So from skewing, the sheet material So gradually skews in the direction of arrow P4. As described above, in the above conventional example, the sheet material skews due to wear of the conveyance roller that conveys the sheet material, so the conveyance roller must be replaced even if it is still usable. However, there was a problem in that it imposed an excessive burden on the user.

Therefore, the present invention has been made to solve the problems of the prior art described above, and its purpose is to provide a sheet material conveying device that can prevent sheet materials from being skewed for a long period of time. .

(Means for Solving the Problem) In order to achieve the above object, the present invention includes a conveyance roller for conveying the sheet material, and a side part of the sheet material is pushed into one side of the sheet material conveyance path. In a sheet material conveying device provided with a sheet material regulating member that regulates the lateral position of the sheet material by hitting the sheet material, the sheet material is moved between the conveying roller and the sheet material regulating member in order to abut the sheet material against the sheet material regulating member. The conveyance speed of the sheet material by the conveyance roller is made different between a portion on the side where the sheet material regulating member is provided and a portion on the side where the sheet material regulating member is not provided, depending on the positional relationship in the conveying direction. Features.

(Function) In general, in a device that conveys sheet material using conveyance rollers, there is a difference in the conveyance speed of the sheet material between the side where the sheet material regulating member is provided and the portion where the sheet material regulating member is not provided. If there is, a force is applied that causes the sheet material to rotate around the portion where the conveyance speed is low.

Therefore, as in the present invention, if the magnitude of the conveying speed is determined according to the positional relationship between the conveying roller and the sheet material regulating member in the sheet material conveying direction, the sheet material can be brought into contact with the sheet material regulating member while It becomes possible to convey sheet materials. As the device is used, even when the conveyance rollers become worn and the outer diameter of the roller on the side with a higher conveyance speed becomes relatively small, the magnitude relationship of the conveyance speeds on both sides of the sheet material does not immediately reverse, and the sheet material It is possible to delay the occurrence of skewed timber.

(Example) Hereinafter, the present invention will be explained based on illustrated embodiments.

1, 2(a) and 2(b) show an embodiment of a sheet material conveying device according to the present invention, and FIG. 2(a)
, (b) shows a schematic configuration of a recording apparatus to which the same embodiment is applied. This recording device forms images by electrophotography, and has a function of recording images on both sides of the sheet material S.

In FIGS. 2(a) and 2(b), reference numeral 1 denotes a cassette for storing sheet materials S, and the sheet materials S are fed out one by one by a paper feed roller 2 from this cassette 1. As shown in FIG. Registration rollers 3 consisting of 3a and 3b are disposed on the downstream side of the sheet material S in the paper feeding direction, and feed the sheet material S at a predetermined timing to the photoreceptor 4 rotating at a constant speed. Incidentally, known primary and transfer chargers, a developer, a cleaner, etc. (not shown) are arranged around the photoreceptor 4. Then, on the downstream side of the photoreceptor 4 in the sheet material conveying direction, a sheet material S
A fixing roller 5 consisting of a pair of rollers 5a and 5b is provided for fixing the toner image transferred thereon.

Here, in the single recording apparatus, in order to record images on both sides of the sheet material S, a switchback means 6, a preliminary shift roller 7, a slow feed roller 8. A sheet material reversing mechanism consisting of a horizontal registration plate 9 and a refeed roller 10 is provided.

The switchback means 6 is disposed on the downstream side of the fixing device 5 in the sheet material conveyance direction, and includes a pair of rollers 6a and 6b that can perform one reversal. Then, the conveying direction of the sheet material S is switched, and the preliminary shift roller 7 located below
The sheet material S is conveyed toward (arrow A direction).

The preliminary shift rollers 7 are a pair of rollers 7a.

Two pairs of rollers 7b are arranged in parallel, but the direction of their rotational axes is inclined in the opposite direction to the horizontal resist plate 9, as shown in FIG. 2(a).

The oblique feed roller 8 is a roller 8 similar to the rollers 7a and 7b described above.
It is equipped with one roller pair consisting of rollers a and 8b. and,
This oblique feed roller 8 has its rotation axis inclined toward the horizontal resist plate 9 in order to abut the sheet material S against the horizontal resist plate 9 provided on the left side in the sheet material conveyance direction. Incidentally, a chamfered portion 9a is formed at the leading end of the horizontal resist plate 9 for smooth conveyance of the sheet material S.

The paper refeed roller 10 is composed of three lower transport rollers, teno drive rollers 10a, 10b, and 10c, and three upper rollers for pressing the sheet material S against each roller 10a to 10c. , and the sheet material S is again fed to the registration rollers 3 by this paper refeed roller lO.

In the above configuration, when recording images on both sides of the sheet material S, the sheet material S is fed out one by one from the cassette l by the paper feed roller 2, and the sheet material S is delivered to the photoconductor 4 at a predetermined timing by the registration roller 3. Then, the sheet material S on which the image has been formed is sent to the fixing device 5 to fix the image, and then conveyed to the switchback means 6. In the switchback means 6, when the rear end of the sheet material S reaches the reversal point 12, the rotation is switched from the rotation for conveying the sheet material S in the direction of arrow B to the rotation for retreating in the direction of arrow C, The sheet material S is conveyed in the direction of arrow A. Furthermore, this sheet material S is moved by the preliminary shift roller 7.
However, in that case, since the preliminary shift roller 7 is inclined in the opposite direction to the horizontal registration plate 9, the sheet material S
are skewed in the same direction, and do not hit the chamfered portion 9a of the horizontal registration plate 9. Then, the sheet material S is hit against the horizontal registration plate 9 by the oblique feed roller 8 to determine the horizontal registration, and then The sheet material S is fed again to the registration roller 3 by the paper refeeding roller 10, and the sheet material S is turned upside down by the above operation, and an image similar to that described above is recorded on the second side of the sheet material S, which is not shown in the drawings. By placing the paper 4a on the tray, the double-sided recording operation is completed.

By the way, in the paper refeed roller 10, as a means for conveying the sheet material S, a drive roller 1O made of rubber is used.
aNIOc (hereinafter referred to as "roller") is used,
Since the rollers 11 are pressed against each roller 10a-10c by a spring or the like, it is practically impossible for these rollers 10a-10c to wear out uniformly.

For example, the roller 10c on the opposite side of the horizontal registration plate 9 wears more than the roller lOa located on the side of the horizontal registration 9,
When the roller 10a becomes relatively large, its conveying force increases, but since the sheet material S is regulated by the horizontal registration plate 9, it will not be skewed.

However, if the roller 10a is worn more than the roller 10c, the sheet material S may be skewed because there is no means for straightening the sheet material S on the opposite side of the horizontal registration plate 9. This will occur.

Therefore, in this embodiment, as shown in FIG. 1, the diameter of the roller 10c on the side opposite to the horizontal resist plate 9 is made small, and for some reason the roller lOa on the side of the horizontal resist plate 9 is Even if it wears more than 10c,
The sheet material S is prevented from being skewed until the diameter of the roller 10a becomes smaller than the diameter of the roller 10c.

That is, the diameter of each roller 10a-10c is Da,
If D b , D c , initially Da = Db
>Dc, forces in the directions of arrows P1 and P2 act on the sheet material S, but since the sheet material S is regulated by the horizontal resist plate 9, skew does not occur, and the force in the direction of the arrow Ao
Conveyed in the force direction. On the other hand, the roller 1 on the side of the horizontal resist plate 9
If roller 0a is worn more than roller 10c, that is, D
When a < D c, forces in the directions of arrows P3 and P4 act on the sheet material S, so that skewing occurs in the direction of arrow P4.

However, in this embodiment, D a > D c
Since Da > Dc, Da
<I) The time to reach c is from Da=Dc to Da
It will be longer than the time it takes to reach < D c .

Therefore, even if roller 10a wears more than roller 10c for some reason, D≧
The relationship De can be maintained, and the timing at which skewing of the sheet material S occurs can be delayed.

By the way, in the above embodiment, as shown in FIG. 2(b), the length of the sheet material conveying path 13 from the paper refeeding roller 10 to the registration roller 3 is short, and it is difficult to convey the sheet material S. Since a relatively large conveying force is required, three rollers 10a to 10c are used. However, for devices that do not require a very large conveying force, two rollers are sufficient to convey the sheet material.
The roller loc on the side opposite to the horizontal registration plate 9 may be omitted, and the sheet material S may be conveyed only by the rollers 10a and 10b. In this case, theoretically, the skew of the sheet material S due to roller wear may be This makes it possible to completely prevent rows.

In addition, when conveying the sheet material S using long rollers such as registration rollers, a tapered roller 20 is used as shown in FIG. It is also possible to arrange the portions facing each other. In this case, it is possible to prevent the sheet material S from being skewed for a long period of time, as in the embodiment described above.

Incidentally, in an apparatus in which the lateral resist plate is located downstream of the conveyance roller in the sheet material conveyance direction, the same effect as in the above embodiment can be obtained by reversing the size relationship of the diameters of the rollers.

Furthermore, as shown in FIG.
Two rollers 30, 31 are provided, and each roller 30, 3
1 are driven by separate motors Ml and M2, and the roller 31 on the opposite side to the horizontal resist plate 9 is driven at a lower rotational speed than the roller 30 on the side of the horizontal resist plate 9. The effect of this can be obtained. In this case, one motor and gears with different reduction ratios are used to drive the roller 30°3.
It is also possible to provide a difference in the number of rotations.

Although the above embodiment has been described using the paper refeed roller 10 as an example, the present invention is not limited to this and can be applied to other rollers. Furthermore, the present invention is applicable not only to the above-mentioned recording apparatus but also to various other apparatuses.

(Effect of the invention) According to the present invention having the above configuration and operation.

Even when the conveying roller is worn out in a biased manner, the sheet material does not immediately skew, and as a result, the sheet material can be prevented from skewing for a long period of time.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a schematic configuration of essential parts of an embodiment of a sheet material conveying device according to the present invention, and FIG. 2(a). (b) shows a schematic overall configuration of a recording device to which the same embodiment is applied, where (a) is a plan view, (b) is a front view, and FIG. 3 is another embodiment of the present invention. FIG. 4 is a plan view showing a schematic configuration of essential parts of still another embodiment of the present invention, and FIG. 5 is a plan view showing a schematic configuration of essential parts of a conventional sheet material conveying device. It is a diagram. 3... Registration roller 8... Oblique feed roller 9...
Lateral registration plate (sheet material regulating member) 10... Re-feeding rollers 10a, 10b, 10cm-- Drive roller (conveyance roller) 11... Roller S... Explanation of sheet material code

Claims (2)

[Claims] (1) A sheet material equipped with a conveyance roller for conveying the sheet material, and a sheet material regulating member that regulates the lateral position of the sheet material by abutting the side of the sheet material on one side of the sheet material conveyance path. In the conveying device, in order to abut the sheet material against the sheet material regulating section, the conveying speed of the sheet material by the conveying roller is adjusted according to the positional relationship in the sheet material conveying direction between the conveying roller and the sheet material regulating member. A sheet material conveying device characterized in that a portion on a side where the sheet material regulating member is provided and a portion on a side where the sheet material regulating member is not provided are different. (2) When the conveyance roller is composed of multiple rollers arranged on the same axis and the sheet material regulating member is located upstream from the conveying roller in the sheet material conveying direction, the conveyance on the side where the sheet material regulating member is provided is The outer diameter of the conveying roller on the side where the sheet material regulating member is not provided is made slightly smaller than the outer diameter of the roller, and when the sheet material regulating member is located downstream of the conveying roller in the sheet material conveying direction, the sheet material regulating member is 2. The sheet material conveying device according to claim 1, wherein the outer diameter of the conveying roller on the side where the sheet material regulating member is not provided is slightly larger than the outer diameter of the conveying roller on the side where the member is provided.