JP2917785B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding device for a printing device such as a copying machine or a printer.

[0002]

2. Description of the Related Art In recent years, plain paper has come to be used from the viewpoint of high image quality and high storability of printed matter, and low reliability due to high reliability of paper feeding and reduction of the number of parts have been recently used. Cost reduction is required.

[0003] An example of a conventional paper feeder will be described below with reference to the drawings. FIG. 7 shows an entire cross section of a conventional plain paper copying machine. Referring to FIG. 1, reference numeral 101 denotes a paper feeding device, which includes a manual paper feeding unit 101a and a cassette paper feeding unit 101b. First, paper is stacked on the manual feed tray 117 in the manual feed unit 101a.

Next, in the case of the cassette sheet feeding section 101b,
The difference from the manual sheet feeding unit 101a is that the portion where the sheets are stacked is not the manual tray 117 but the cassette 121.

An outline of the operation of the main body will be described below. A light source 104 is applied to a document 103 placed on a document surface glass 102.
And irradiate the light with the reflecting mirrors 105 to 108 and the lens 10.
9, an optical image is formed on the photoconductor 110. A latent image is formed on the photoreceptor 110 corresponding to the light image, developed into a toner image by a developing device, and the toner image is transferred by a transfer unit 111 onto a sheet sent by a sheet feeding device 101. Conveying means 1
The sheet is sent to the fixing unit 113 by the fixing unit 113, and the toner image is fixed on the sheet by the fixing unit 113, and then stored in the sheet discharge tray 115 through the sheet discharge unit 114.

Next, the details of the paper feeding unit 101 will be described. In the cassette paper feeding unit 101b, reference numeral 121 denotes a paper cassette, and 122 denotes a cassette bottom plate for pressing the paper in the paper cassette 121 against the feed roller 123 with an appropriate pressure. Reference numeral 124 denotes a paper feed roller for separating the paper fed by the feed roller 123 one by one and feeding the separated paper into the apparatus. Reference numeral 125 denotes a sabaki roller facing the paper feed roller 124. The paper fed by the paper feed roller 124 and the sabaki roller 125 is fed by paper guides 126 to 12.
8 guides the nip between the registration roller 129 and the backup roller 130. The registration roller 129 and the backup roller 130 rotate in synchronization with the image on the photoconductor 110, and the sheet is transferred to the transfer unit 111. The same applies to the manual paper feed unit 101b. The paper fed by the feed roller 118 is separated one by one by a paper feed roller and a sabaki roller, and the paper guide guides the sheet between the nip between the registration roller 129 and the backup roller 130. You are being led.

Next, the structure of the reversing roller mechanism in the conventional sheet feeding device will be described in detail with reference to FIG.
FIG. 8 is a configuration diagram showing a driving mechanism of a sheet feeding roller mechanism of a conventional sheet feeding device. In FIG.
Reference numeral 5 denotes a sabaki roller; 131, a driving gear for driving the sabaki roller 125;
32 and the driving gear 131.
Three are wound. The operation of the sheet feeding device configured as described above will be described below.

In FIG. 7, the sheet fed by the feed roller 123 to the nip position between the sheet feeding roller 124 and the sub-roller roller 125 is not always guaranteed to be sent one by one, and a plurality of sheets may be sent. At this time, the driving gear 131 shown in FIG. 8 is driven so as to always rotate the sabaki roller 125 in the direction opposite to the sheet feeding direction. The winding spring wound in a direction loosened with respect to the rotation direction of the driving gear 131 slides on the driving gear 131 with a certain frictional resistance. If the frictional resistance at this time is set to be larger than the frictional resistance between the sheets and smaller than the frictional coefficient between the sheet and the roller, when one sheet is fed to the nip between the sheet feeding roller 124 and the sabaki roller 125 shown in FIG. When the paper feed roller 124 is rotated, the driving gear 131 and the wrapping spring 133 are integrated with each other to reverse the paper feed direction. Is rotated in the direction of pushing back the sheet, and the sheet is pushed back toward the sheet cassette 121 sequentially from the sheet below the plurality of sheets sent to the nip position.

FIG. 9 shows a configuration of a paper pressing release mechanism in a conventional paper feeding device. Cassette 1 loaded with paper 116
Reference numeral 21 denotes a sheet 11 when mounted on the cassette sheet feeding 101b.
The cassette bottom plate 122 is not pressed so that the sheet 6 does not interfere with the feed roller 123 and breakage of the sheet occurs. When the cassette is mounted in the proper position, the cam lever 135 having a cam shape or the like provided on the side surface of the cassette moves, and the cassette pressing means 134 attached via a spring.
Lifts the cassette bottom plate 122. Further, when the cassette is detached, the mechanism is such that the pressing of the sheet is released.

[0010]

However, in the above configuration, a paper feeding roller in the cassette and a paper feeding roller in the manual paper feed unit are separately required. That is, as the number of paper feed units increases, the number of rollers also increases, leading to an increase in cost, and the elongation of the paper path of the copying machine leads to a reduction in paper feed reliability. If the cassette is pulled out to the front of the copier with the paper in the cassette being fed by the feed roller, the paper will be pulled out with the paper sandwiched between the paper feed roller and the Sabaki roller, causing paper damage. Eventually, the rollers may be damaged. Driving means for rotating the sub-roller in the direction of pushing the paper back into the cassette is required, and the friction between the boss portion and the winding spring must be controlled by the respective dimensions, thereby increasing the cost of the driving system for the driving gear and reducing the cost. It is necessary to control the frictional force of the winding spring. In order to feed thick small paper such as postcards and business cards by the conventional manual feed tray, it is desirable to make the paper feeding path as straight as possible because the paper is strong and has high resistance, but this leads to an increase in the size of the device. . And many other issues.

In view of the above problems, the present invention reduces the number of rollers in a manual paper feed unit and shortens the paper path of a copying machine by using both a roller of a manual paper feed unit and a driving roller of a registration roller. It is intended to provide a paper feeding device for achieving the above. By moving the Sabaki roller in the direction of attachment / detachment of the paper cassette in conjunction with the paper cassette when attaching / detaching the paper cassette, it is possible to prevent remaining paper in the copier, damage to the paper, and damage to the rollers and the like. A paper feeder is provided. An object of the present invention is to provide a sheet feeding device that simplifies an input drive system to the sabaki roller by accumulating a load at the time of reverse rotation of the sabaki roller during the rotation. An object of the present invention is to provide a paper feeding device in which the feeding path of thick small paper is made as straight as possible to improve the copy quality of thick small paper such as postcards and business cards.

[0012]

In order to solve the above problems, a paper feeder according to the present invention comprises: a paper feeder for feeding paper in a paper feed cassette one by one; and a manual feeder for feeding the paper one by one. Paper feed means, and a pair of registration rollers for temporarily stopping the fed paper and transporting the paper in synchronization with image formation, wherein one of the pair of registration rollers is also used as a paper feed roller of the manual paper feed means. It is provided. A paper cassette that is removable in the front-rear direction of the device body,
A sheet feeding unit for feeding the sheets in the sheet cassette one by one; and a pair of registration rollers for temporarily stopping the fed sheet and conveying the sheet in synchronization with image formation. It is an object of the present invention to provide a sheet feeding device in which the sheet feeding means is moved in the direction of attachment / detachment of the sheet cassette in conjunction therewith so that no sheet remains when the sheet cassette is attached / detached. A paper feeder comprising a paper feed roller and a sabaki roller for separating sheets fed one by one in cooperation with the paper feed roller, wherein the paper feed device is provided with a fixed shaft and a rotatable shaft. A driven spring and a driven boss, a torque spring wound around both the driven roller and the driven boss, and a return spring having one end substantially fixed to the driven boss and substantially fixed to a portion not related to the driving of the driven boss. It is comprised by these. A paper feed cassette, a paper feed roller for feeding out the paper in the paper feed cassette, separating means for separating the paper one by one, and a pair of registration rollers for temporarily stopping the fed paper and feeding it in synchronization with image formation. The paper feed roller has a shape in which a part having an arc surface substantially equal to or slightly longer than the distance from the paper separating portion to the registration roller is partially cut, and when feeding paper, the arc of the paper feed roller is provided. The sheet rotates to a first position where the sheet is sent out to the registration roller and stopped, and a second position where the cut surface that rotates in synchronization with the operation of the registration roller and does not contact the sheet stops against the sheet. It is configured to be controlled.

[0013]

According to the present invention, by using the above-mentioned configuration, the registration roller and the manual feed roller for the paper sent from the paper feed cassette are used, and the reliability of the paper feed path in the manual paper feed and the cassette feed is shortened, thereby improving reliability. Cost reduction can be achieved by reducing the number of rollers. When the paper feed cassette is attached or detached, the mackerel roller moves in the attaching / detaching direction of the cassette, so that there is no pressing force between the paper feed roller and the mackerel roller, and the paper is stored in the paper cassette and does not remain in the paper feeder. . Since the separating force is accumulated when the sub-roller rotates with the paper feed roller, it is not necessary to separately drive the paper pushing-back force to the sub-roller. By feeding thick small-sized paper using an arc-shaped roller, the paper is straightened from the cutout when feeding the paper feed roller, and smooth conveyance can be performed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A paper feeder according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view showing the overall configuration of a printing apparatus according to a first embodiment of the present invention. FIG. 1 shows an entire cross section of a plain paper copying machine using the paper feeding device of the present invention.

The outline of the operation of the main body will be described below. A light source 4 irradiates a document 3 placed on a document surface glass 2 with a light source 4 to form a light image on a photoreceptor 10 by reflecting mirrors 5 to 8 and a lens 9. A latent image is formed on the photoreceptor 10 corresponding to the light image, developed into a toner image by a developing device, and the toner image is transferred by a transfer unit 11 onto a sheet fed by the sheet feeding device 1. The sheet is sent to the fixing unit 13 by the conveying unit 12, the toner image is fixed on the sheet by the fixing unit, and then stored in the sheet discharge tray 15 through the sheet discharge unit 14.

The paper feeder 1 has a plurality of cassette paper feeders 1a and 1b corresponding to different paper sizes from a manual paper feeder having a manual feed tray 17, and can feed three types of paper. By adding a paper feed unit, the types of paper that can be used simultaneously can be increased.

Referring to FIG. 2, the details of the sheet feeding section 1 will be described. In the drawing, reference numeral 21 denotes a paper feed cassette, and reference numeral 22 denotes a cassette bottom plate for pressing the paper in the paper feed cassette 21 against the paper feed roller 24 with an appropriate pressure. 25 is the paper feed roller 2
This is Sabaki Roller who faced No.4. The paper fed by the paper feed roller 24 and the sabaki roller 25 is
It is guided between the nip between the registration roller 29 and the backup roller 30 by 6 and 27 and is fed to the photoconductor 10. At this time, the registration roller 29 is also used as a manual feed roller when the sheet is fed from the manual feed tray 17, and the diameter of the registration roller 29 is equal to or slightly larger than that of the backup roller 30 so as to smoothly feed the sheet during manual sheet feeding. It has become. When the copying machine starts the copying operation, the registration roller 29 and the backup roller 30 start rotating in synchronization with the image, and the sheet is transferred to the transfer unit 11.

FIG. 3 illustrates the structure and the operation of the sheet feeding device that are linked when the sheet feeding cassette is attached and detached.

In the configuration shown in FIG. 3, the paper feed cassette 21 is mounted, but when the paper feed cassette 21 is not mounted, the paper feed roller 24 and the sabaki roller 25 are displaced in the axial direction. ing. This is because when the paper stops due to a paper jam for some reason, the paper cassette 2
1 to make it easier to remove the paper. When the paper feed cassette 21 is mounted on the apparatus (the state shown in the figure), the detachable lever 41 moves in the direction of arrow a by the end surface of the paper feed cassette 21 to move the paper feed roller 24 to a position facing the sub-roller roller 25. At this time, the release spring 42 attached to the detachable lever 41 is pulled. When the sheet cassette 21 is pulled out of the apparatus in this state, the detachable lever 41 pressed on the end face of the sheet cassette 21 moves in the direction of arrow b by the restoring force of the release spring 42, and the sheet cassette is mounted. The paper feed roller 24 returns to the position where it is not performed.

Next, referring to FIG. 4, the behavior of the roller 25 and the mechanism of the roller will be described.

In the drawing, reference numeral 25 denotes a sabaki roller, and 36 denotes a sabaki roller shaft. The sabaki roller 25 is rotatably supported with respect to the sabaki roller shaft 36. Reference numeral 37 denotes a driven boss rotatably supported by a mab roller shaft 36;
Numeral denotes a torque spring wound around the boss portion of the saw roller 25 and the driven boss 37. Reference numeral 39 denotes a return spring wound around the maw roller shaft, and reference numeral 40 denotes a slipper for fixing one end of the return spring 39.

The operation of the sub-roller mechanism configured as described above will be described. As shown in FIG. 1, the paper fed by the paper feed roller 24
And reach between the nips. At this point, the number of sheets sent to the nip is not necessarily one. That is, a state in which one sheet is fed (state A) and a state in which two or more sheets are fed (state B) are considered. In the case of state A. Friction between the paper feed roller 24 and the paper Two frictional portions occur, that is, the friction between the paper and the Sabaki roller 25. Further, in the case of state B, three frictional portions, namely, friction between the paper feed roller 24 and the paper, friction between the paper and the sabaki roller 25, and friction between the paper and the paper are generated.

In both the states A and B, the coefficient of friction is generally high and is about 1 to 1.6. In the case of the state B, the coefficient of friction is generally low and is about 0.6 to 1.

Next, the relationship of the torque spring 38 wound on both the boss portion of the sub-roller roller 25 and the driven boss 37 shown in FIG. 4 will be described. In the winding direction of the torque spring 38, the sub-roller roller 25 rotates along with the paper feed roller 24. When rotated in the direction, the torque spring 38 itself is wound in a loosening direction.
Further, the inner diameter of the torque spring 38 in the free state is slightly smaller than the outer diameter of both bosses, so that when the sub-roller roller 25 rotates with the paper feed roller 24, it rotates while generating some slip torque. In other words, when the feeding roller 25 rotates with the feeding roller 24, the driven boss 37 is driven via the torque spring 38.
Also rotates in the rotation direction of the rotation roller 25. Driven boss 3
When the return spring 39 whose one end is substantially fixed is tightened or loosened (depending on the winding direction of the reverse rotation coil, either one holds), a rotation torque opposite to the rotation direction is accumulated, and the sliding torque of the torque spring 38 and the return torque are returned. When the accumulated torque of the spring 39 becomes equal, the driven boss 3
The rotation of 7 stops.

As described above, under the condition that the friction between the paper and the paper is not included (state A), the rotation roller 25 rotates along with the paper feed roller 24. That is, one sheet is fed between the nips, and the coefficient of friction is large. Further, until the sheet is fed, the coefficient of friction between the two rollers is even larger than in the state where one sheet is fed, and the same operation as described above is performed. Further, since the return torque of the return spring 39 is configured to be larger than the torque based on the friction coefficient between the paper and the paper, when two or more papers are fed in a state where the rotational torque is accumulated in the return spring 39 ( (In the case of state B) The frictional coefficient is small, and the rotational torque accumulated in the return spring 39 prevails, and the rotation of the paper feed roller 24 in the direction opposite to the co-rotating direction is performed by the
Will be given to. As a result, the sheets that come into contact with the roller 25 are sequentially pushed back into the paper feed cassette 21 and are repeated until the last sheet is reached, so that only one sheet can be fed.

FIGS. 5A and 5B illustrate the behavior of the paper feed roller when feeding paper in the embodiment. FIG. 5A is a cross-sectional view showing a state before the sheet feeding operation, that is, immediately after the sheet feeding cassette 21 is mounted, and a state where the sheet feeding operation is completed. In this case, the cassette bottom plate 22 formed inside the paper feed cassette 21 pushes the paper up to a regular position when the paper feed cassette 21 is mounted. On the other hand, the cross-sectional shape of the paper feed roller 24 is D-shaped at the above-mentioned two positions where the paper does not come into contact even when the paper is pushed up to the normal position and does not come into direct contact with the Sabaki roller 25.
1 can smoothly perform the separation / disconnection and paper jam processing.

FIG. 5B shows the state of the paper feed roller 24 in which the paper feed roller 24 rotates in the direction B and feeds the paper, after which the paper reaches the nip between the registration roller 29 and the backup roller 30, and the photosensitive member The state while waiting for synchronization with the above image is shown. The paper roller 25 and the paper feed roller 24 hold the paper between the nips, and the paper is pressed against the registration roller 29 and the backup roller 30, so that the cue of the paper is reliably performed.
In other words, the D-shaped stop position of the paper feed roller 24 is at the position where the paper in the paper feed cassette 21 does not come into contact with the sabaki roller 25 (FIG. 5A). , And the repetition of the operation is a sheet feeding operation.

FIG. 6 is a configuration diagram of the manual feed tray 17.
The first manual feed tray 17a and the second manual feed tray 17a
The first manual tray 17a has a notch 18 of a size such as a postcard or a business card.
Is given. When thick small paper, such as a postcard or business card, is loaded on the first manual toilet 17a, it falls from the notch to the second manual tray 17b, and a D-shaped registration roller having a central portion slightly wider than the width of the postcard paper. 29
Conveyed by Many small papers are thick papers such as postcards and business cards, and the above-described manual tray configuration and the D shape applied to the registration rollers 29 enable direct paper conveyance. Other large sheets such as A4 and B4 are sent by the first manual feed tray 17a. Since the first manual feed tray 17a has a larger size in the sheet feeding direction than the second manual feed tray 17b for loading large-sized paper such as A4 and B4, the first manual feed tray 17a is slightly angled so as to suppress the size of the apparatus main body.

The paper having a size smaller than the postcard size is often thick and stiff, and the second manual feed tray is used to prevent the paper conveyance force by the rollers from losing the stiffness of the paper and to prevent slipping. 41, and a linear feed is performed at the D-shaped portion of the registration roller 29,
The configuration does not depend on the waist of the paper.

[0031]

As described above, the present invention relates to a paper feeder provided with a paper feed roller and a sabaki roller which cooperates with the paper feed roller to separate sheets fed one by one. A shaft, a sabaki roller and a driven boss rotatably provided on the shaft, a torque spring wrapped around both the sabaki roller and the driven boss, and one end of the sabaki roller substantially fixed to the driven boss. Simplification of a mechanism that can generate a paper return force during multi-feeding of paper without the need to rotate the Sabaki roller by using a return spring that is substantially fixed to parts that are not related to driving.
Cost reduction can be achieved. The roller having one of the larger diameters of the pair of registration rollers is also used as the paper feed roller of the manual paper feeder, so that the number of rollers is reduced, the paper conveyance path length of the cassette paper feed, and the paper of the manual paper feed. The transport path length can be reduced. By providing a mechanism in which the paper feed roller and the separation roller come into contact with each other in accordance with the attachment / detachment of the paper feed cassette, it is possible to realize a paper feeder that does not damage the paper when the paper feed cassette is pulled out. The shape of the paper feed roller has a partially cut arcuate surface that is approximately equal to or slightly longer than the distance from the paper separation point to the registration roller, which simplifies the mechanism.
Cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing the overall configuration of a copying machine having a paper feeding device according to the present invention.

FIG. 2 is a cross-sectional view of the sheet feeding device of the present invention.

FIG. 3 is a perspective view showing a position of a sheet feeding roller in the sheet feeding device of the present invention.

FIG. 4 is a cross-sectional view of a sheet roller in the sheet feeding device of the present invention.

FIG. 5 is a cross-sectional view illustrating a sheet feeding roller unit in the sheet feeding apparatus of the present invention.

FIG. 6 is a perspective view illustrating a configuration of a manual feed tray according to the present invention.

FIG. 7 is an overall sectional view of a conventional plain paper copying machine.

FIG. 8 is a cross-sectional view of a conventional paper feeder.

FIG. 9 is a cross-sectional view showing a paper pressing mechanism in a cassette of a conventional paper feeding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Paper feeder 2 Document surface glass 3 Document 4 Light source 5-8 Reflector 9 Lens 10 Photoreceptor 11 Transfer unit 12 Conveying unit 13 Fixing unit 14 Discharge unit 15 Discharge tray 17 Manual feed tray 18 Notch 21 Paper feed cassette 22 Cassette bottom plate 24 Paper feed roller 25 Sabaki roller 26 Paper guide 27 Paper guide 29 Registration roller 30 Backup roller 36 Sabaki roller shaft 37 Follower boss 38 Torque spring 39 Return spring 41 Detachable lever 42 Release spring

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-2-38244 (JP, A) JP-A-2-57852 (JP, U) JP-A-2-31241 (JP, U) (58) Survey Field (Int.Cl. ⁶ , DB name) B65H 1/00-3/68 B65H 11/00-11/02

Claims (1)

(57) [Claims] 1. A sheet feeding unit for feeding sheets in a sheet cassette one by one.
Paper feeder and manual paper feeder to feed the paper one by one
Means and temporarily stop the fed paper to perform image formation.
And a pair of registration rollers for transporting
Feed one of the pair of distrollers into the paper feed
Of the pair of registration rollers.
Of the registration roller that also serves as the paper feed roller
The diameter must be larger than the diameter of the other registration roller
A sheet feeding device characterized by the above-mentioned.