JPS6175753A - Original text sheet transport device - Google Patents

Abstract

PURPOSE:To eliminate skew and jam with an original text sheet when they are inserted by moving a pressure roller through utilization of rotation of the drive shaft after insertion of an original, thereby pressing the original to the original transportation surface and rotating the pressure roller. CONSTITUTION:When an original text sheet 1 inserted has reached a transport roller 6, a drive shaft 11 drives the roller 6 to transport the original. At the same time, this rotation of drive shaft 11 is transmitted to a coupling 12 to rotate in the same direction as the drive shaft 11 against the action of a spring 15, so as to press a pressure roller 13 to the original transportation surface 2. Now the pressure roller 13 rotates oppositely to the above-mentioned transport roller 6 owing to contact therewith. Consequently the original 1 receives light tension between the transport roller 6 and pressure roller 13, and is transported by the transport roller 6 while being in close contact with the original transport surface 2. This may eliminate skew or jam with originals likely to occur when they are inserted.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a document conveying device in an optical reading device such as a facnography or OCR device.

Conventional configurations and their problems In recent years, various types of optical reading devices have been developed, such as fan scanning, OCR, etc. One of the important points in such an optical reading device is a device for preventing the document from shifting from the focal plane of the optical system in the optical axis direction during conveyance of the document, and various devices have been proposed.

A conventional document conveying device will be described below.

FIGS. 4 and 5 show a conventional document conveying device, with FIG. 4 showing the document before the document is inserted, and FIG. 5 showing the document being conveyed after the document is inserted. In FIGS. 4 and 5, 1 is a document, 2 is a document conveying surface, 3 is a light source, 4 is a lens, and 5 is a light receiving element.

6 is a conveyance roller, and in opposition to this is a pinch roller 7.
is rotatably provided and is pressed against the conveying row 26 by a spring 8. Reference numeral 9 denotes a floating prevention member, which is rotatable around the bottle 10.

Regarding the conventional document transport device configured as described above,
The operation will be explained below.

First, in FIG. 4, before the original 1 is inserted, the floating prevention member 9 is in contact with the original transport surface 2 due to gravity.

In FIG. 2, when the original 1 is inserted, the floating prevention member 9 is pushed up by the original 1, and then the original 1 is transported by the transport roller 6, which starts rotating upon sensing by a sensor (not shown). That is, the original 1 is pressed against the original transport surface 2 by the floating prevention member 9, and the original 1 comes into close contact with the original transport surface 2 between the transport roller 6 and the floating prevention member 9.

However, with the above configuration, the anti-floating member is in contact with the conveyance surface when inserting the document, which creates resistance to document insertion. Especially when the document is made of thin, smooth paper, it may be impossible to insert the document, or the document may become bent or jammed. This has the problem of causing problems such as.

OBJECTS OF THE INVENTION The present invention solves the above-mentioned problems of the conventional art.Before inserting a document, the floating prevention member is retracted from the document conveying surface.
By holding down the original after it is inserted, it is possible to eliminate paper bending and paper jams when inserting the original, and by taking the movement of the anti-floating member from the rotation of the transport roller, there is no need for a dedicated drive source such as a solenoid. The purpose of the present invention is to provide a document conveying device that does not.

Structure of the Invention The document conveyance device of the present invention includes a conveyance roller for conveying the document, a connecting member that is attached to the rotating shaft of the conveyance roller with viscous resistance and that pivotally supports the conveyance roller, and a pressure roller which is pivotally supported by a connecting member, whose outer periphery is in contact with the outer periphery of the transport roller, and which is disposed on a side opposite to the transport direction of the document from the transport roller; and a pressure roller that urges the pressure roller toward the side opposite to the document and a pinch roller that is provided in pressure contact with the conveyance roller and pinches and conveys the document.When inserting the document, the floating prevention member is retracted from the document conveyance surface, and the document is conveyed after the document is inserted. By pressing it against the surface, it is possible to prevent paper bending and paper jams when inserting a document.

DESCRIPTION OF THE EMBODIMENTS FIGS. 1 and 2 show a document conveying device according to an embodiment of the present invention. FIG. 1 shows the document before the document is inserted, and FIG. 2 shows the document after the document is inserted. In FIG. 1, 11 is a drive shaft, and this drive shaft 11 is rotated with viscous resistance (
For example, a connecting member 12 is provided (for example, by applying highly viscous grease to the sliding surface). A press roller 13 is provided at the other end of the connecting member 12 and is rotatable in contact with the conveying roller 6.

In order to retract the pressing roller 13 so as not to interfere with the insertion of the original 1, a spring 16 is hooked between the connecting member 12 and a pin 14 provided on the main body.

Note that 1 is a document, 2 is a document conveyance surface, 3 is a light source, 4 is a lens, 5 is a light receiving element, 6 is a conveyance roller, 2 is a pinch roller, and 8 is a spring, which are the same as the conventional example. be.

The operation of the document conveying device of this embodiment configured as described above will be described below.

First, in FIG. 1, the original 1 is not inserted, and the pressing roller 13 is retracted from the original transport surface 2 by the force of the spring 15. Next, in FIG. 2, when the document 1 is inserted and reaches the conveyance roller 6, a sensor (not shown) senses this, and the conveyance roller 6 begins to rotate by the drive shaft 11 and begins to feed the document 1. At the same time, the rotation of the drive shaft 11 is transmitted to the connection member 12 via viscous resistance, and the connection member 12 starts rotating in the same direction as the rotation of the drive shaft 11 against the force of the spring 16. At the same time, the pressing roller 213 presses the
is rotated in the opposite direction to the rotation of the transport row 26 due to contact with the transport row 26. At this time, the document 1 is conveyed by the conveyance roller 16 while being brought into close contact with the document conveyance surface 2 under a slight tension between the conveyance roller 6 and the pressing roller 13 . Here, the pressure roller 6 and the document 1 slip. Figure 3 shows the force relationship at this time. Here, W is spring 8
Pressure force due to μ. is the coefficient of friction between the transport roller 6 and the document 1, F is the transport force, and the following relationship holds between them.

F=μ. W......
(1) Also, assuming that ω is the angular velocity of the drive shaft 110, μ is the viscous resistance coefficient between the drive shaft 11 and the connecting member 12, and r is the radius of the sliding surface, the torque T transmitted to the connecting member 12 is given by the following equation. T=μ・(rω)2 ・・・・・・(
2) The force W applied to the pressure roller 13 is the force Fs caused by the force thorn 18 due to this torque T. When the distance between the axes of the pressure roller 13 and the conveyance roller 6 is e, the force W is: w=T −1−Fs =p(rov)2・1−Fs
=−・−(3). If the frictional forces between the pressing roller 13 and the original 1 and between the original 1 and the original transport surface 2 caused by this pressing force W are f', , fl, respectively, then f
l: μmw, fl: μ2W (
4). Here, μm and μ2 are respective friction coefficients. Substituting equation (3) into equation (4), f'+=t, t
, (μ(rω)26−Fs).

f2=μ2(μ(rω)2e−Fs) ・−−(5
) In the above, the following equation must hold between the conveying force F and the frictional forces f, , fl.

2) 11・fl ・・・・・・
(6) Also, μ from equations (1) and (5). W) μm (μ(rω)d−Fs).

μ2(p (r ω)2(l Fs ) −−(7
) Konoke) It is necessary to set each position so that the formula holds true.

As described above, according to this embodiment, the pressure roller is retracted from the document conveyance surface before the document is inserted, and after the document is inserted, the pressure roller is moved using the rotation of the drive shaft to press the document against the document conveyance surface. Furthermore, the pressure roller is rotated by the rotation of the conveyance roller, applying light tension to the document and bringing it into close contact with the document conveyance surface, thereby preventing the document from shifting in the optical axis direction from the focal plane of the optical system in the optical reading device. Moreover, it is possible to prevent deterioration of insertability, paper bending, and paper jam when inserting a document.

Effects of the Invention As is clear from the above description, the present invention retracts the pressure roller from the document conveyance surface before inserting the document, moves the pressure roller using the rotation of the drive shaft after the document is inserted, and moves the document to the document conveyance surface. By using the rotation of the conveyance roller to rotate the pressure roller to apply light tension to the document and bring it into close contact with the document conveyance surface, the document is prevented from shifting from the focal plane of the optical reading device. Furthermore, it is possible to realize an excellent document conveying device that improves the insertion property when inserting a document and can prevent paper bending and paper jamming.

[Brief explanation of the drawing]

FIG. 1 is a front view of a document conveying device according to an embodiment of the present invention in a state before a document is inserted, FIG. 2 is a front view of the document conveying device in a state after a document is inserted, and FIG. FIG. 4 is a front view showing the force relationship, FIG. 4 is a front view of a conventional document conveying device in a state before the document is inserted, and FIG. 5 is a front view of the document conveying device in a state after the document is inserted. 1... Original, 2... Original transport surface, 6.
...Conveyance roller, completed...Pinch roller,
12... Connection member, 13... Pressing row 2.15... Spring. Name of agent: Masu Toshio Nakao and 1 other person, s
= Evening 2 Figure

Claims (1)

[Claims] a conveying roller for conveying a document; a connecting member that is attached to the rotating shaft of the conveying roller with viscous resistance and pivotally supporting the conveying roller; and a connecting member that is pivotally supported by the connecting member and whose outer periphery is a pressure roller provided in contact with the outer periphery of the roller and disposed on the opposite side of the document conveyance direction from the conveyance roller; a resilient member that biases the pressure roller toward the opposite side of the document; and a resilient member in pressure contact with the conveyance roller. A document conveying device equipped with a pinch roller that is provided to pinch and convey a document.