JPS63277139A - Paper feeding device - Google Patents

Abstract

PURPOSE:To make a device small size and low cost and to carry out accurate paper conveyance by providing a means of conveying a sheet material in cooperation with a feeding means on the lower course side in the sheet material conveying direction of a separating means. CONSTITUTION:Transfer materials 1 on a paper feeding tray 2 are pressed against a paper feed roller 4 by means of a paper feeding pressure spring and, as the paper feed roller 4 is rotated, the ends of the transfer materials 1 are advanced up to a paper guide 2' by friction reaching a separating pad 6. And, plural piled sheets of transfer paper 1 come to stop from the sheet whichever comes in close vicinity to the separating pad 6 earlier and, due to friction, only one sheet of transfer paper 1a passes through between the paper feed roller 4 and the separating pad 6, arrives at a roller 7 which is driven being pressed by the paper feed roller 4, and the sheet of paper 1a is held in between and conveyed. Thereupon, the conveying speed vp of the transfer material 1a is stabilized since the pressing force of the roller 7 against the paper feed roller 4 is sufficiently large with respect to the friction load between the transfer material 1a and the separating pad 6. Hence, the accurate conveyance can be carried out, enabling a device to be low cost and small size and to perform accurate paper conveyance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a paper feeding device used in an image forming apparatus such as a copying machine or a printer.

[Conventional technology A conventional example is shown in FIG.

The transfer material stacked on the paper feed tray 2 is pressed against a feed roller 4 by a paper feed pressure spring 3. When the feeding roller 4 rotates, the leading edge of the transfer material (sheet material) 1 enters the paper guide 2' due to friction. one for the coefficient of friction between the plurality of sheets of the transfer material l that has entered, one for the coefficient of friction between the feeding roller 4 and the transfer material l, and one for the separation pressure spring 5 on the feeding roller 4. Therefore, the relationship between the friction coefficient w2 between the pressed separation bat 6 and the transfer material l is as follows.

It is configured so that <#Lz<pz.

μ, <μ2, the plurality of overlapping transfer materials 1 are conveyed or stopped from the one closest to the separation pad 6, and finally the J
l. Since 2<g:+, only one transfer material la is conveyed passing between the feeding roller 4 and the separation bat 6 (see FIGS. 12 and 13). Immediately after passing between the feeding roller 4 and the separation bat 6, the conveyance speed Va at which the transfer material 1a is conveyed is unstable because it changes due to a harance of μ1μ2μ3. After the leading edge of the transfer material 1a is held between the pair of register rollers 13 and 14, the feeding roller 4
The drive is cut.

A one-way clutch (not shown) is attached to the feeding roller 4, and the feeding roller 4 is rotated by friction between the transfer material 1a and the feeding roller 4. When the rear end of the transfer material la leaves the feed roller 4, the feed roller 4 stops rotating and the primary transfer material 1b is not transported. Since the pressing force acting between the pair of register rollers 13 and 14 is sufficiently large compared to the frictional load between the transfer material 1a and the separation bat 6, the conveyance speed vb for conveying the transfer material 1a is stabilized. On the other hand, the light beam 9 emitted from the optical scanning section 8 forms an image on the photoreceptor lO to form a latent image, and the latent image is developed with toner by a developing device. The toner image on the photoreceptor lO is transferred to the transfer material 1a at point P. The toner image on the transfer material la is fixed by a fixing device 12.

[Problem to be solved by the invention] In the above-mentioned conventional example, a pair of register rollers 13 and 14 was used to stabilize the speed at point P where transfer is performed, and an accurate image was obtained. The disadvantages of using a pair were that the space was large and the cost was high.

[Means for Solving the Problems (and Effects)] According to the present invention, there is a loading means capable of loading sheet materials, a feeding means for feeding out the sheet materials, and a sheet feeding means that cooperates with the feeding means to load the sheet materials. In a sheet feeding device equipped with a means for separating sheet materials, by providing a means for conveying sheet materials in cooperation with the feeding means on the downstream side of the separating means in the sheet material conveying direction, the paper feeding device can be made cheaper, smaller, and more accurate. This makes it possible to carry out paper conveyance.

[Example] FIG. 1 shows an embodiment of the present invention.

The transfer material 1 loaded on the paper feed tray 2 is pressed against the feed roller 4 by the paper feed pressure spring 3 . When the feeding roller 4 rotates, the leading edge of the transfer material 1 enters the paper guide 2' due to friction. A friction coefficient 3 between the plurality of sheets of the transferred transfer material 1 that has entered, a friction coefficient 3 between the feeding roller 4 and the transfer material 1, and a pressure applied to the feeding roller 4 by a separation pressure spring 5. The relationship between the friction coefficient μ2 between the separated separation bat 6 and the transfer material l is such that <JL2<gz. The conveyance of the plurality of overlapping transfer materials 1 is stopped by the wheel 1 and the roller 2, starting from the one closest to the separation bat 6, and finally, the conveyance of the transfer material 1a is stopped by the wheel 2 It passes between the roller 4 and the separation bat 6, reaches the driven roller 7 that is pressed by the feeding roller 4, and is conveyed while being held between the feeding roller 4 and the roller 7 (Fig. 2). , 3rd
(See figure) The pressing force of the roller 7 on the feeding roller 4 is sufficiently large compared to the frictional load between the transfer material 1a and the separation bat 6. After being nipped by the transfer material la, the conveyance speed v2 of the transfer material la becomes stable.

On the other hand, the light beam 9 emitted from the optical scanning section 8 forms an image on the photoreceptor 10 to form a latent image, and the latent image is developed with toner by a developing device 11. The toner image on the photoreceptor lO is transferred to the transfer material 1a at point P. The transfer material 1a is the photoreceptor l
When the feeding roller 4 is sandwiched between the feeding roller 21 and the transfer roller 21, the drive to the feeding roller 4 is released. A one-way clutch bearing 4d is integrated with the feed roller 4, and after the drive to the feed roller 4 is released, it rotates following the transfer material 1a due to frictional transmission. When the rear end of the transfer material 1a passes the point where the feed roller 4 and the roller 7 contact (point Q), the feed roller 4 stops, and the next transfer material 1b stops at a slightly moved position. do. The toner image on the transfer material lb is fixed by a fixing device 12.

When the feed roller 4 completes the feeding operation of the transfer material 1a and a certain period of time has elapsed, the solenoid 22 (see FIG. 8) is activated, and the claw 22b and the protrusion 4e of the cam plate are separated, and at the same time the feeding is completed. The driving of the feed roller 4 is started again, and the next transfer material 1b is fed, and the state 1H in FIG. 7 is again achieved.

The above operations are repeated to feed the third and subsequent sheets.

FIG. 4 is an axial direction explanatory view of the vicinity of the feeding roller of the present invention.

The rotation of the feed roller 4 is transmitted to the roller 7 by pressing the roller 7 with a tension spring 15. 16 is a bearing.

In addition, the timing of writing the image on the photosensitive weight 0 and the transfer material l
A switch SW or the like is effective as a means for registering with the tip of the tip. In other words, writing (irradiation) may be started at the same time (or a little later) when the tip of the sheet or the switch SWI is pressed. This is determined by the distance between switch SW (or point Q) and point P, and the distance from three points on photoreceptor IO to point P.

In addition, to measure the timing, use the switch SW as shown above.
1 may be omitted, and control may be performed using a timer from the start of paper feeding by the paper feeding roller 4.

[Other Embodiments] A main sectional view and an axial direction explanatory view of the vicinity of the feeding roller of another embodiment (1) are shown in FIGS. 5 and 6, respectively. Through the same process as in the embodiment of the present invention, the leading edge of the transfer material 1a reaches point P. In parallel with the movement of the transfer material 1a reaching point P, the cam plate 4c mounted on the feed roller shaft 4b is rotating, until the leading edge of the transfer material 1a reaches point P. The core A6 feed roller 4 and roller 7 are in contact with each other.

(See Figure 7). Immediately after the tip of the transfer material 1a reaches point P, it is regulated by the control ring 4e or pawl 22b of the solenoid 22, and stops at the position where the cam plate 4c abuts the spacer 7C, as shown in FIG. . At this time, the input gear 23 is rotating or the shaft 4b is stopped. When the cam plate 4c comes into contact with the roller, the feeding roller 4 and the roller 7 are separated from each other. This condition is.

Returning to FIG. 5, this is the state in which the rollers have been moved to the position of roller 7 or 7'. At this time, the feeding roller 4 is driven to rotate mainly due to friction with the transfer material 1a at the R point. When the rear end of the transfer material 1a passes through point R, the feeding roller stops rotating, and the next transfer material 1b is not transported. When it is desired to more accurately control the interval between a transfer material and the next transfer material in the process after paper is fed, the structure of this other embodiment is effective.

FIG. 9 shows an axial direction explanatory view of the vicinity of the feeding roller of still another embodiment (2). In this case, in this embodiment, gears 17 and 1
8 has been added.

The rotation of the feed roller 4 is transmitted to the roller 7 via gears 17,18. At this time, the gear ratio of the gears 17 and 18 is set so that the peripheral speeds of the feeding roller 4 and the roller 7 are the same.

An axial direction explanatory view of the vicinity of the feeding roller of another embodiment (3) is shown in FIG. In this case, gears 17j9 and 18.20 are added to the present embodiment. Rotation of the feed roller 4 is transmitted from gear 19 to gear 17, while rotation of the roller is transmitted from gear 20 to gear 18.

At this time, it is also possible to independently change the peripheral speed of the feeding roller and the peripheral speed of the roller.

[Effects of the Invention] Since the paper feeding device according to the present invention has the configuration 5 described above, it is possible to convey paper accurately and has the effect of improving printing quality. It also has the effect of being cheaper and smaller.

[Brief explanation of the drawing]

Fig. 1 is a main sectional view of this embodiment, Fig. 2 is a sectional view of the vicinity of the feeding roller of this embodiment, Fig. 3 is a sectional view of the vicinity of the feeding roller of this embodiment, and Fig. 4 is a sectional view of the vicinity of the feeding roller of this embodiment. FIG. 5 is a main sectional view of another embodiment (1); FIG. 6 is an explanatory diagram of another embodiment (1) in the vicinity of the feed roller in the axial direction; FIG. FIG. 7 is a diagram showing the contact state of the feeding roller and the roller in another embodiment (1), FIG. 8 is a diagram showing the separation state of the feeding roller and the roller in another embodiment (1), and FIG. 9 The figure is an explanatory view of the axial direction near the feed roller of another embodiment (2). Figure 10 is an explanatory view of the axial direction of the vicinity of the feed roller of another embodiment (3). Figure 11 is the main cross section of the conventional example. 12 is a sectional view of the vicinity of the feeding roller of the conventional example, and FIG. 13 is a sectional view of the vicinity of the feeding roller of the conventional example. l is the transfer material (multiple sheets) la is the transfer material (one sheet) 2 is the paper feed tray 4 is the feed roller 6 is the separation pad 7 is the roller

Claims (2)

[Claims] (1) A loading means capable of loading sheet materials; a feeding means for sending out the sheet material; Separating the sheet material in cooperation with the feeding means A paper feeding device comprising: The sheet material is conveyed in cooperation with the feeding means. The means for conveying the sheet material by the separating means Paper feeding device characterized by being provided on the downstream side Place. (2) The paper feeding device according to claim 1, characterized in that the conveying means is provided on a member that comes into contact with and separates from the feeding means.