JPS584093Y2 - Copy machine sheet conveyance device - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a sheet conveying device for a copying machine.

For example, in a copying machine as shown in FIG. 1, a document and a sheet as a recording medium are both fed through an inlet 1
It is exposed through the exposure section 2 and discharged from the intermediate discharge port 3.

Here, the original is collected, and only the exposed sheet is continuously fed through the intermediate feeding port 4, reversed in the reversing conveyance section 5, and then passed through the developing section I while being guided by the sheet guide plate 6. The sheet is developed and discharged from the sheet discharge port 8 to obtain a copied sheet.

To introduce the conventional technology related to the exposure section 2 and the reversing conveyance section 5, as shown in FIG. The reversing conveyor section 5 includes a reversing roller 11 having an outer diameter d smaller than that of the cylindrical light source 9, and an intermediate roller 10 disposed opposite to the reversing roller 11. It consists of a facing roller 12 arranged therein.

Furthermore, the exposure section 2 and the reversing conveyance section 5 are connected by a belt 13 having a thickness of t, and this belt 13 presses along the curved surface of the cylindrical light source 9, and after winding around the intermediate roller 10, It is routed along the curved surface of the reversing roller 11 so as to come into pressure contact with it.

When copying the above-mentioned pass b1, the original 14 and the sheet 15 are stacked and sent through the inlet 1, and then pressed against the surface of the cylindrical light source 9 by the belt 13.
It is exposed to light while being conveyed along with the image.

Of the original 14 and sheet 15 sent out from the cylindrical light source 9 in this way, the original 14 is collected when it comes out of the intermediate discharge port, but the leading edge of the sheet 15 continues to be copied through the intermediate feed port 4. The facing roller 12 is fed into the machine.
It is inserted into the pressure contact portion between the belt 13 and the belt 13, and is conveyed toward the developing section 7 along with the movement of the belt 13.

By the way, in the above process, when an oval sheet is used as the sheet 15, after the rear end of the sheet 15 is completely removed from the circumferential surface of the cylindrical light source 9, the tip of the sheet 15 is
There is no problem if the sheet is conveyed by being sandwiched between the opposing roller 12 and the belt 13, but if a large sheet is used as the sheet 15, the rear end of the sheet 15 is connected to the circumferential surface of the cylindrical light source 9. At the same time that the sheet 15 is pressed against the belt 13, the leading edge of the sheet 15 gets caught between the facing roller 12 and the belt 13 and is conveyed, and as time passes,
The slack in the sheet 15 that existed between the exposure section 2 and the conveyance section 5 gradually decreases, and finally, the slack disappears.
When the sheet 15 is conveyed, the tension between the exposure section 2 and the conveyance section 5 becomes strong, so the load on the motor (not shown) that drives the belt 13 increases, or wrinkles may occur during diagonal feeding. The disadvantage is that it occurs.

An object of the present invention is to provide a sheet conveying device for a copying machine that eliminates the above-mentioned drawbacks.

The above-mentioned drawback arises from the fact that the feeding speed of the sheet 15 in the reversing conveyance section 5 is higher than the feeding speed of the sheet 15 in the exposure section 2. Equal, or reversing conveyance section 5
The above-mentioned drawbacks can be overcome by making the feed speed at the exposure section 2 slower than the Q feed speed at the exposure section 2.

The above-mentioned difference in speed is caused by the fact that the belt 13 is thick.

That is, when the belt is wound around the roller, the belt is bent into an arc shape, and at this time, the outer side of the belt stretches, the inner side contracts, and the approximately central part of the thickness does not stretch or contract.

The velocity at the center of the thickness is the same value no matter where it is measured at any point when one continuous belt moves.

In the portion wrapped around the roller, the speed of the surface portion located on the outside of the roller is greater than the speed of the thickness center portion.

It has been confirmed through experiments that in the configuration of a conventional copying machine, the outer peripheral speed of the cylindrical light source 9 (inner speed of the belt 13) is approximately equal to the speed at the center of the thickness of the belt 13.

Therefore, if the feeding speed of the sheet 13 in the exposure section 2 is V, this is approximately equal to the speed at the center of the thickness of the belt 13.

Therefore, if the speed at the center of the thickness of the belt 13 in the reversing conveyance section 5 is V, and the number of rotations per unit time of the reversing roller 11 is n, then the following equation is obtained.

On the other hand, if the speed of the pressure contact portion between the belt 13 and the opposing roller 12 in the reversing conveyance section 5 is vl, then the above /1)
Using the formula, the velocity v1 can be expressed as follows.

In the above equation (2), d = 21.7r as an actual value
Substituting ranz t=1.2m, v1=1.05
v is obtained, and it can be seen from this that the sheet feeding speed at which the exposure section 2 is pressed is 5 times greater than the sheet feeding speed at which the reversing conveyance section 5 is pressed.

In the present invention, the sheet feeding speed in the exposure section 2 and the reversing conveyance section 5 is adjusted by means described below.

Its structure, as shown in FIGS. 3 and 4, is that the conventional facing roller 12 is replaced with a large roller 17 and a small roller 18 fixed to a shaft 16. 17 also has a large diameter reversing roller 11,
Moreover, it is in pressure contact with the reversing row 211, thereby transmitting rotation to the shaft 16.

Further, the small roller 18 is slightly spaced apart from the outer circumference of the belt 13 (7).

However, the amount of this separation needs to be smaller than the thickness of the sheet 15.

Therefore, the radius of the small roller 18 is smaller than the radius of the roller 11 by the thickness t of the button belt 13.

Next, in order to maintain an appropriate degree of pressure contact, the bearing 16a of the shaft 16 and the bearing 1 of the shaft 19, which is integral with the reversing roller 11, are
An elastic material 20 is wound around the shaft 9B, and functions to keep both shafts close to each other at all times.

In addition, considering the case where the thickness of the sheet to be conveyed is extremely small, due to slight manufacturing errors, the small roller 18 and the belt 13 are always in pressure contact regardless of the presence or absence of the sheet. It may also be a configuration.

However, even in this case, no particular problem arises in obtaining the effects of the present invention.

That is, what is necessary is to obtain a situation in which, when a sheet to be conveyed and held is interposed between the small roller 18 and the belt 13, the small roller 18 and the belt 13 are simultaneously pressed against the sheet. Also, it does not matter whether or not the small roller 18 and the belt 13 are pressed against each other in a situation where the sheet is not present.

In the present invention, the reversing roller 11 is rotated by the belt 13, and the large roller 17 is rotated according to the rotation of the reversing roller 11.
is rotated, the rotational speed is reduced here, and the small roller 18 is rotated by this reduced rotation.

The sheet 15 to be conveyed is conveyed by the belt 13 and small rollers 18.
and is conveyed at approximately the average speed of both.

In Figure 4, the speed at the center of the thickness of the belt 13 is v1.
The number of revolutions per unit time of the reversing roller 11 and the shaft 16 are each n*nt, the outer diameter of the reversing roller 11 is d1, the outer diameter of the dog row 211 is dl, the outer diameter of the small roller 18 is d2, and the reversing roller 11 peripheral speed (peripheral speed of dog roller IT)
If v2 is the circumferential speed of the small row 218 and v3 is the circumferential speed of the small row 218, then the following equation holds true.

v=n(d+t)π・・・・・・・・・・・・・・・(
3) V2 = n1d1 From equation (4), π2naπ ・・・・・・・・・・・・・・・(5) From equations (5) and (6), the circumference of small roller 18 The speed v3 is v3""d2n1π, and by substituting equation (7) into this equation, the following equation is obtained.

Substituting the values used in the experiment, d1=24Φ, d2222Φ, d=21.7Φ, and 21.27/a into the upper phase equation 8 to find v3, we get v3"" O-869v. obtain.

In this state, when the sheet 15 is inserted between the belt 13 and the small roller 18, the sheet 15 has a speed v = 1.0
5v, sent at a rate of 0695-0.97v, which is approximately the average rate of v3=0.869v.

This speed is the feeding speed v1=l, Q5 in the exposure section 2.
It is smaller than V.

That is, the sheet feeding speed in the exposure section 2 and the sheet feeding speed in the reversing conveyance section 5 are balanced, and the drawbacks mentioned at the beginning are eliminated.

[Brief explanation of drawings]

Fig. 1 is a diagram schematically showing the configuration of a copying machine suitable for carrying out the present invention, Fig. 2 is a side sectional view of the main part of a sheet conveying device illustrating the drawbacks of the prior art, and Fig. 3 is a diagram schematically showing the structure of a copying machine suitable for implementing the present invention. FIG. 4 is a perspective view of the reversing conveyance unit showing the structure of the invention, and a side view of the same with a sheet inserted. 2... Exposure section, 5... Reversing conveyance section, 9
......Cylindrical light source, 10...Middle lawn, 11...Reversing roller, 13...Belt, 17...Large roller, 18・・・・・・Little roller.

Claims (1)

[Scope of utility model registration request] At the exposure part, press along the curved surface of the external cylindrical light source,
In a sheet conveying device of a copying machine, the sheet conveying device of a copying machine has a belt that is wound around an intermediate roller and then wrapped around the belt so as to press against the curved surface of the reversing roller having an outer diameter d in a reversing conveying section consisting of a pair of rollers. The roller facing the
The rollers are replaced with two types of rollers, a large roller and a small roller, which have the same shaft and different diameters, and the large roller made with a larger diameter than the reversing roller is brought into pressure contact with the reversing roller, and the small roller is replaced with the reversing roller. 1. A sheet conveying device for a copying machine, characterized in that the sheet conveying device for a copying machine is configured to press against the outer periphery of a belt that is passed around the belt through a sheet to be conveyed.