JPH0445035A - Original transport device - Google Patents

Abstract

PURPOSE:To keep off any skewing motion as well as stabilize the extent of conveyance by constituting the circumference of a feed roller with a pilelike rubber sheet, while forming an intervalve between this rubber sheet and a fulcrum shaft with a hard material part at the central neighborhood of this feed roller, a range from both the symmetrical ends to the outside of original width with soft foam sponge roller, respectively. CONSTITUTION:The circumference of a feed roller 4 is formed with a pipelike rubber sheet 4d, while an interval between this rubber sheet 4d and a fulcrum shaft 4c is formed with a hard material at the central neighborhood 4a of the feed roller 4. In addition, a range 4b from both the symmetrical ends to the outside of width of an original sheet S is formed with a soft foam sponge roller. With this constitution, conveying force at the vicinity of the central part of the original range is made larger but this force at both the symmetrical ends is made smaller up to the utmost, through which any skewing motion of the original sheet S is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a document conveying device, and particularly to one used in an image reading device such as a facsimile machine that closely reads an image of a document.

[Conventional technology]

As a conventional document conveyance device of this type, there is one used in a conveyance system of a document reading device, such as the one shown in FIG. 5, for example. This conveyance system includes a front-stage conveyance roller 100 with which a separation piece 101 for separating documents comes into contact, and a contact type image sensor (hereinafter referred to as C5) as a document reading means.
102 . The document 104 is separated and fed one by one by the front conveyance roller 100 and is conveyed by the rear conveyance roller 103, while the information on the document 104 is sequentially read by the image sensor 102. This front conveyance roller 100
The and rear conveyance roller 103 are operated in conjunction with each other via a gear train by a reading drive motor (not shown). On the other hand, the timing at which the image sensor 102 reads the document 104 is determined based on a detection signal from a document edge sensor 107 provided between the front conveyance roller 1oo and the rear conveyance roller 103.

Since C3 (contact sensor) has a shallow depth of field,
If the document were to float off the CS, the quality of the read image would deteriorate, so as shown in Figure 6, the conveyance roller was pressed against the CS during the middle of the document to prevent the document from floating. . Here, the conveyance roller is made of hard rubber and manufactured with highly precisely defined surface flatness.

[Problem that the invention is trying to solve]

However, the above conventional example had the following drawbacks.

(1) As mentioned above, the conveyance roller is made of hard rubber and is in pressure contact with C3 throughout the meal, so there is a uniform conveyance force throughout the meal. Therefore, if the document is skewed for some reason and only one edge of the document is eaten before it is bitten by the transport roller, the load of the separation roller is on the upstream side. There is a problem in that a force couple acts on both the left and right ends of the document, increasing the skewed feeding of the document as shown in FIG.

(2) As mentioned above, the conveyance roller needs to be in close contact with the C3 throughout the feeding to prevent the document from lifting even slightly, but if there are depressions or protrusions on the surface of the O5 or the conveyance roller, the conveyance roller Since the C5 and C3 are separated from each other, the surfaces of the C5 and the conveyance roller are manufactured with the flatness controlled with high precision, which leads to an increase in costs.

(3) If C3 is brought into close contact with C8 by strongly pressing against the conveying roller and slightly deforming the surface of the roller, the conveying force will increase. That is, a motor with torque sufficient to withstand this load is required, but the size of the motor generally increases in proportion to the torque, leading to an increase in the size and cost of the device.

An object of the present invention is to reduce the torque of the drive system for conveying the document as described above and prevent skewing of the document, thereby stabilizing the document conveyance and making it easier to manufacture the conveyance roller.

[Means for Solving the Problems (and Effects)] According to the present invention, the outer periphery of the conveying roller is made of a pipe-shaped rubber sheet, and the area between the pipe-shaped rubber sheet and the support shaft is formed near the center of the conveying roller. It is made of hard material, and the range from the left and right edges to the outside of the document width is made up of soft foam sponge rollers, which increases the conveying force near the center of the document and minimizes the conveying force at the left and right edges. Make it smaller to prevent the document from being skewed.

In addition, by making the outer diameter of the foamed sponge roller somewhat larger than the outer diameter of the hard material part, the outer diameter of the pipe-shaped rubber sheet of the conveying roller is made slightly larger in the foamed sponge roller part than in the hard part. When the document is pressed against the conveyance roller, the foamed sponge roller is slightly deformed, pushing the document and preventing the document from floating.

〔Example〕

The present invention will be explained below based on the illustrated embodiment.6 A document conveying device according to an embodiment of the present invention will be shown. In FIG. 1, 1 is a frame that constitutes the outer frame of the device, and this frame 1
A conveyance path P through which a sheet-like original S is conveyed is provided within the conveyance path C.

In the conveyance path P, a document receiving plate 2, a front conveyance roller 3 as a front conveyance means, a rear conveyance roller 4 as a rear conveyance means, and a document discharge guide plate 5 are arranged in this order from the A side in the conveyance direction.

The front conveyance roller 3 is arranged below the conveyance path P, and the document S
A separation plate 6 constituting document separation means is pressed above the separation plate 6 via a support plate 61 by a spring member (not shown).

On the other hand, the rear conveyance roller 4 is arranged at a predetermined interval on the downstream side of the front conveyance roller 3 in the conveyance direction. are pressed together by a leaf spring or the like.

The reading means 7 includes a flat substrate 71, as shown in FIG.
It includes a receiving part 72 including a photoelectric conversion element provided on the upper surface, and a light source 73 such as a cannon tube provided below the substrate 71. The light receiving section 72 is constructed by disposing a photoelectric conversion element 75 on a transparent plate 4 such as a glass plate, and covering the photoelectric conversion element 75 with a transparent thin plate 76 from above.

The photoelectric conversion element 75 is located at the contact portion of the rear conveyance roller 4 and sequentially reads the document S illuminated by the light source 73 through a through hole 77 provided in the substrate 71.

The operation of the above configuration will be explained.

The document S inserted into the conveyance path P is detected by the facsimile main body by the document detection sensor 10 that detects the presence or absence of a document, and the front conveyance roller moves clockwise and the rear conveyance roller 4 moves clockwise.
rotate counterclockwise. The document is conveyed downstream by the frictional force between the front conveyance roller 3 and the separation plate 6, and after the leading edge of the document hits the document edge detection sensor 11, it is further conveyed a predetermined distance and is sandwiched between the rear conveyance roller 4 and the reading means 7. , the image is read while being conveyed further downstream. After that, the trailing edge of the document is detected by the document edge detection sensor 11.
When the document passes by and has been conveyed a predetermined distance, the reading operation ends and the document is discharged onto the document discharge guide plate 5.

Next, FIG. 3 shows a longitudinal cross section near the rear conveyance roller, which is a feature of the present invention. FIG. 3 shows a state in which the outer diameter of the foaming roller 46 that is in contact with the original S is deformed when the original S is bitten.

Here, 4a is a cylindrical hard roller made of plastic, and 4b is a cylindrical foamed roller made of foamed rubber, each of which is integrally formed with a support shaft 4C by adhesive or the like. Reference numeral 4d denotes a thin pipe-shaped rubber sheet, which is wound around the outer circumferences of the hard roller 4a and the foamed roller 4b and is integrally formed with adhesive or the like.

The roller portion of the rear conveyance roller 4 is symmetrical with respect to the front conveyance roller 3 in the longitudinal direction with respect to the center, and has a width larger than the width of the original document.

The width of the hard roller 4a is set to be somewhat wider than the width of the front conveyance roller 3.

The outer periphery of the hard roller 4a is manufactured so that the flatness is controlled to be less than the depth of field of the reading means 7. Further, the outer diameter of the foaming roller 4b is set to be somewhat larger than the outer diameter of the hard roller. As a result, the rubber sheet 4d extends along the outer peripheries of the hard roller 4a and the foaming roller 4b, so the outer diameter of the rubber sheet 4d is also larger at the left and right sides than at the center.

The above configuration has the following effects.

(1) $4 As shown in the figure, the document S is placed on the rear conveyance roller 4.
If the document is skewed for some reason and only one edge of the document is bitten before the document 1 is bitten, the load F2 of the separation roller and the force of the rear transport roller 4 to bite one edge of the document. F1 acts as a couple on the document Sl, but since the inside of the rubber sheet 4d is a soft foam roller 4b, the conveyance force F at one end of the roller is small, and the couple hardly acts on the document. , the skew does not increase.

Further, when the document is conveyed downstream and becomes the document s2, the document is bitten near the center of the rear conveyance roller 4, and a conveyance force FF acts on the document. Here, rubber sheet 4
d is near the center because there is a hard roller 4a inside,
The conveying force F is a high force for conveying the document. Through the above-described operation, the document is stably conveyed without increasing skew.

(2) Next, the state in which a document is conveyed and read will be explained. As mentioned above, near the center of the document, the rubber sheet 4d follows the outer periphery of the hard roller 4a, which has a highly flat outer periphery, and the outer periphery of the rubber sheet 4d also has a high flatness. The image can be read well if the images are placed in close contact with each other.

In the left and right ranges other than the center of the document, as described above, the outer diameter of the rubber sheet 4d is larger than the central part, so when the rubber sheet 4d hits the reading means 7, the foam roller 4b is on the inside, so the foam roller 4b is slightly deformed. That is,
The outer periphery of the rubber sheet is also slightly deformed to prevent the original from floating and come into close contact with the reading means 7, allowing the image to be read satisfactorily.

(Other examples) Other examples are shown below.

(1) In this example, as a general case, the outer diameter of the foaming roller was set larger than the diameter of the hard roller, but this ratio was determined by the flatness of the foaming roller, hard roller, and contact image sensor. The same effect can be obtained even if it is changed depending on convenience, the depth of field of the contact image sensor, etc.

(2) In this embodiment, the hard roller is made of plastic resin, but the same effect can be obtained if it is made of hard material such as metal.

(3) If the support shaft is made of hard material, the same effect can be obtained by cutting the support shaft into steps and also serving as the hard roller section.

(4) In this example, the image was read with a contact type image sensor, but a glass plate was brought into contact with the conveyance roller, and the conventional C
A similar effect can be obtained in a reduction optical system using a CD.

As explained above, the structure is such that the document is read by placing the conveyance roller in direct contact with the contact image sensor. By changing the location, the following effects can be obtained.

(1) Since the conveyance force at the left and right ends of the conveyance roller is small, even when the document separation means is located upstream of the conveyance, there is little couple force acting on the document, and the skew of the document does not increase, resulting in good reading.

(2) The flatness of the surface of the conveyance roller only needs to be controlled with high accuracy on the hard rubber roller part, and the flatness of the foamed sponge roller part can be controlled more roughly, making it easier to manufacture parts and improving yields, reducing costs. goes down. Furthermore, the flatness of the surface of a contact type image sensor is similarly roughly managed, resulting in a similar effect.

(3) It is no longer necessary to deform the transport roller or image sensor using strong pressure to bring the surface of the transport roller into close contact with the image sensor, reducing the driving load, reducing the size of the motor, and reducing costs. I can do it.

〔Effect of the invention〕

The document conveying device according to the present invention does not cause skew feeding of the document, and
This has the effect of allowing smooth transportation.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a document conveying device embodying the present invention, Fig. 2 is a cross-sectional view illustrating a reading means of a document conveying device embodying the present invention, and Fig. 3 is a cross-sectional view of a conveyance roller, which is a feature of the present invention. 4 is a plan view for explaining the skewed document feeding state in the embodiment, FIG. 5 is a sectional view of a conventional document conveying device, and FIG. 6 is a sectional view of a conventional document conveying device. FIG. 3 is a plan view for explaining a skewed document state. 3 is a front conveyance roller, 4 is a rear conveyance roller, 4a is a hard roller, 4b is a foaming roller, 4c is a spindle, 4d is a pipe-shaped rubber sheet, 6 is a separating plate, 7 is a reading means, S is a document sheet S

Claims (2)

[Claims] (1) In a document conveyance device that reads a document while conveying the document by directly contacting a conveyance roller with a contact image sensor, etc., the outer periphery of the conveyance roller is constructed of a pipe-shaped rubber sheet. A document conveyance device characterized in that the portion between the conveyance roller and the support shaft is made of a hard material near the center of the conveyance roller, and the range from the left and right ends to the outside of the width of the document is made up of soft foamed sponge rollers. (2) By making the outer diameter of the foamed sponge roller larger than the outer diameter of the hard material part, the outer diameter of the pipe-shaped rubber sheet of the conveyance roller is made slightly larger in the foamed sponge roller part than in the hard material part. A document conveying device according to claim (1), characterized in that: