JPH0479938B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document feeding device for a copying machine, and more particularly, it is provided with a plurality of drive rolls and driven rolls, and a sheet document is inserted between the rolls to feed the copying machine. The present invention relates to a document feeding device that transports a document onto a platen.

[Conventional technology]

Conventionally, a document feeding device for transferring a sheet-like document onto the platen of a copying machine is disposed on the top surface of the copying machine main body 1, as shown in FIG. A plurality of drive rolls 2 made of a material of
A driven roll 3 is provided above and below, and is formed of a soft foam such as rubber or plastic, and is supported by a bearing so as to be rotatable in the direction of arrow B as the drive roll 2 rotates; A device is known that includes a document guide 4 attached between rolls 3.

According to this device, the sheet-like original 5 is
Since documents can be continuously fed onto the platen 6 by simply inserting them one by one with the copy side facing up, copying operations can be performed while checking the copy side of the original, and the occurrence of copy errors can be significantly reduced. In addition, the present invention has the advantage that the operation of opening and closing the platen cover, which was conventionally required for each copying operation, is no longer necessary, and the operability of the copying machine can be significantly improved.

However, in this device, as shown in FIG. 1, the copy surface of the original 5 comes into contact with the driven roll 3, so the surface of the driven roll 3 is easily soiled by the original 5, and especially when a large number of pencil originals are inserted. If this occurs, the pencil dust may accumulate on the surface of the driven roll, and this accumulated pencil dust may be transferred to a newly inserted document, staining the document, and Copies also have the disadvantage of being unclear, and this disadvantage is particularly noticeable in multi-mode document feeders that automatically circulate and repeatedly convey documents.

In order to overcome this drawback, a document feeding device has been proposed in which an aluminum roll whose surface is anodized is used in place of the driven roll. This type of roller has minute irregularities on the surface of the driven roll, which prevents pencil dust from adhering to the original and is effective in removing stains on the original.However, in the case of a multi-mode document feeder, each driven In order to equalize the roll pressure between the roll and the drive roll, a spring must be provided for each driven roll, which poses a problem in that the apparatus becomes large and expensive.

[Purpose of the invention]

The present invention eliminates and improves the drawbacks of the prior art described above, and provides a document feeder equipped with a plurality of drive rolls and driven rolls, in which the outer peripheral surface of the driven roll is covered with a rubber elastic body, and An object of the present invention is to provide a document feeding device which prevents pencil dust from adhering to a driven roll by coating its surface with resin to prevent pencil dust from adhering to it, and thereby does not stain copied originals. It is.

[Structure of the invention]

That is, the present invention provides a document feeding device including a plurality of drive rolls and a plurality of driven rolls made of soft foam, in which the outer circumferential surface of the soft foam layer of the driven rolls is covered with a rubber elastic body, and further By covering the surface with a coating film or film made of resin to which pencil powder does not adhere, the pencil powder is prevented from adhering to the surface of the driven roll, thereby preventing the copy document from becoming stained;
This makes it possible to obtain clear copies.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 2 and 3.
This will be explained with reference to the figures. 2 shows a partial side view of the document feeding device of the present invention, and FIG. 3 shows a perspective view of the driven roll of the present invention.

That is, as shown in FIG. 2, the document feeding device of the present invention includes a plurality of drive rolls 7 and driven rolls 8, 8 that are pressed against the top and bottom of the drive rolls 7, respectively.
and a document guide 9 attached between each of the driven rolls 8.

First, the drive roll 7 is made of chloroprene rubber, and is supported by a support shaft 10 so as to be rotatable in the direction of arrow A.

On the other hand, the driven rolls 8 and 8 are provided above and below the drive roll 7, respectively, as shown in FIGS. It is coated with a rubber elastic body 12, and its surface is coated with a polytetrafluoroethylene resin film 1 that prevents pencil powder from adhering to it.
3 and the drive roll 7
It is supported by a support shaft 14 so as to be rotatable in the direction of arrow B with the rotation of the support shaft 14 .

Further, an appropriate pressure is applied between the driving roll 7 and the driven rolls 8, 8 by a mechanism not shown.

The spaces between each driven roll 8 are connected by a document guide 9, as in the conventional document feeder shown in FIG. 1, and the inserted document is guided by this document guide 9 and conveyed onto the platen surface. It is configured to do this.

In the present invention, as described above, the surface of the driven roll that comes into contact with the copying surface of the original is coated with a resin film that prevents pencil dust from adhering to it. There is no possibility that it will stick to the surface and accumulate.

Therefore, the document inserted through the document feeder will not be smeared with pencil dust or the like accumulated on the surface of the driven roll, unlike in the conventional case, and clear copies can be obtained.

In addition, in the present invention, since a rubber elastic body is interposed between the soft foam of the driven roll and the above-mentioned resin film that does not allow pencil powder to adhere, its elastic force allows the nip pressure with the drive roll to be applied. Accordingly, the degree of deformation or distortion of the driven roll that occurs can be reduced, thereby improving the stability of document conveyance.

In order to confirm the effects of the driven roll in the document feeder of the present invention, a comparative test was conducted using the test machine shown in FIG. 5 using the three types of driven rolls shown in FIG. 4.

FIG. 4 shows a cross-sectional view of each driven roll, where A shows a conventional driven roll made of foamed chloroprene 15, and B shows a conventional driven roll made of polyester film 1, which has a property that prevents pencil powder from adhering to the surface of the roll.
6 shows the coated driven roll, and C shows the driven roll used in the above example.

Further, the testing machine is composed of a movable table 17 that reciprocates in the direction of the arrow as shown in FIG. 5, and a fixing member 18 provided above the movable table 17 to fix each of the driven rolls.

The test method is as shown in Figure 5.
A document 19 with a plurality of straight lines drawn in pencil on tracing paper is placed on the movable table 17, and a driven roll 2 is fixed above it with a fixing material 18.
The movable table 17 was reciprocated many times in the direction of the arrow, and the degree of contamination of each of the driven rolls 20 and the original 19 due to pencil powder was measured (Test 1).

Next, the movable table 17 is fixed, the driven rolls 20 are set on it, compressed for 24 hours to deform the driven rolls 20 under pressure, and then released to determine the amount of residual deformation of each driven roll 20 due to changes over time. (Residual distortion amount)
was measured (Test 2).

As a result, measurement results as shown in FIGS. 6 and 7 were obtained. In other words, Figure 6 shows the results of Test 1, and the degree of dirt on the manuscript etc. due to pencil powder is as follows:
It shows that the conventional driven roll in (a) is the worst, and the driven rolls in (b) and (c) are much less.

On the other hand, FIG. 7 shows the results of Test 2, and shows that the amount of residual deformation of the driven roll (B) is the largest, and the amount of residual deformation of the other rolls (A) and (C) is small.

As is clear from the measurement results, it was confirmed that the driven roll used in the above example was the most excellent in terms of staining due to pencil dust and residual deformation due to nip pressure.

In the above embodiment, polytetrafluoroethylene is used as the resin to which pencil dust does not adhere to the driven roll, but other resins such as polyester, polyimide, polyvinyl chloride, etc. can also be used.

〔Effect of the invention〕

As described above, the present invention has a structure in which the outer peripheral surface of the soft foam layer of the driven roll is coated with a rubber elastic body, and the surface is further coated with a coating film or film film made of resin to which pencil powder does not adhere. Therefore, no matter how many times a document written in pencil is passed through the roller, pencil powder from the document does not adhere to and accumulate on the surface of the driven roll.

Therefore, the inserted document is not smudged by the driven roll, and a clear copy can be obtained.

Furthermore, even if the driving roll and the driven roll are kept in pressure contact with each other for a long time without being operated, the degree of deformation or distortion of the driven roll is small due to the elastic force of the rubber elastic body, so that the conveyance of the original is not hindered. The practical effects of the present invention are enormous.

[Brief explanation of the drawing]

FIG. 1 shows a side sectional view of a conventional document feeding device, and FIGS. 2 and 3 show embodiments of the present invention, and FIG. 2 is a partial side sectional view of the document feeding device of the present invention. , FIG. 3 shows a perspective view of the driven roll of the present invention, and FIGS. 4 to 7 show comparative test methods and results for confirming the effects of the present invention. FIG. FIG. 5 shows a side view of the test machine, and FIGS. 6 and 7 are graphs showing the measurement results. Explanation of symbols, 7... Drive roll, 8... Driven roll, 9... Document guide, 10, 14... Support shaft, 1
1... Soft foam, 12... Rubber elastic body, 13...
...Resin film.

Claims (1)

[Claims] 1. In a document feeding device that includes a plurality of drive rolls and a plurality of driven rolls that rotate while being pressed against each other, and that inserts a sheet-like original document between the rolls and transfers it onto a platen of a copying machine, the soft foam layer of the driven roll 1. A document feeding device characterized in that an outer circumferential surface is covered with a rubber elastic material, and the surface is further covered with a coating film or a film film made of resin to which pencil dust does not adhere.