JPH045477Y2 - - Google Patents

Description

[Detailed description of the invention] (A) Industrial application field The present invention relates to paper feeding devices such as copying machines and printers, and more specifically, the invention relates to paper feeding devices such as copying machines and printers. The present invention relates to a paper feeding device equipped with a forward feed roller.

(B) Prior Art Conventionally, image forming apparatuses such as copying machines and printers have been equipped with automatic document feeding mechanisms or stack bypasses in addition to paper sheet feeding cassettes in order to improve the efficiency of copying operations. Therefore, a mechanism is provided that can feed a large number of sheets of paper of a type other than the paper sheets loaded in the cassette.
As shown in Japanese Patent Application No. 60-112399 previously filed by the present applicant, the paper feeding section of these mechanisms includes, in addition to the paper feeding roller, a vertically movable advance roller. In addition, a guide member for easily inserting paper sheets is provided upstream of the forwarding roller in the conveyance direction, and when inserting a large number of sheets into the paper feed section, the upper part of the leading edge of the paper first passes through the guide member. By contacting the guide member and rotating the guide member and bringing it into contact with the shaft of the advance roller, the advance roller is moved against the biasing force, and a predetermined distance is created between the guide member and the paper holder. A device has been devised in which the paper can be easily loaded into a predetermined position in the paper feed section by forming a diaphragm.

However, with the method of pushing the shaft of the forward feed roller upward by providing a guide member, the strength of the guide member must be considerably increased, so one end of the forward feed roller is connected to the main motor via a gear. A drive gear is provided, and a limit switch is provided upstream of the forward feed roller in the conveying direction. When the leading edge of the paper is detected, the main motor rotates, and the drive gear of the forward feed roller also rotates to move the paper to the paper feed section. In addition to feeding the paper to the tip, that is, a predetermined position where it comes into contact with the feed roller, as the drive gear of the forward feed roller that is engaged at this time rotates, a force is applied to raise the forward feed roller. The purpose is to use the force to raise the advance roller and to make it easier to insert the paper into a predetermined position.

(C) Problems to be solved by the invention However, the prior art has the following problems. In other words, in the above case, a lifting force acts on the drive side of the forward feed roller, whereas the other end of the forward feed roller is simply fitted into a long hole provided in the side plate of the paper feed section, so no lifting force acts on it. First, the upward movement of the advance roller is performed in an inclined state, and this tendency is particularly noticeable for small-sized paper. As a result, the pressure of the advance rollers is not applied equally to the left and right sides of the paper, which causes the paper to be fed diagonally.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to prevent the paper from being fed diagonally when the paper is inserted, by raising and holding the advance rollers equally on the left and right in the longitudinal direction.

(D) Means for solving the problem The paper feeding device according to the present invention has a paper feeding roller that feeds paper sheets into the machine body, and a paper feeding roller that transports paper sheets from the paper feeding roller. A plurality of forward feed rollers are provided on the upstream side in the direction and are supported on axes parallel to the axial direction of the paper feed roller and are supported to be movable up and down along guide means provided on the side plate; and a forward feed roller provided on the shaft of the forward feed rollers. a drive member that acts to raise the forward feed roller shaft by being driven by a driving force from a drive source; When paper sheets are inserted into the paper feed section,
The guide member has a guide member that rotates about a shaft in a direction opposite to the pressing direction that is constantly biased to assist in the insertion of paper sheets, and the guide member has at least the advance direction at one end thereof. It has a holding part that extends upwardly at one end of the shaft of the roller on the driving member side, and a receiving part that projects at least downwardly at the other end of the shaft of the forward-feeding roller on the side opposite to the driving member side. It is characterized by this.

(E) Effect When paper is inserted and one end of the driving side of the shaft of the advance roller rotates and rises, one end is held down by the holding part provided on the guide member, and at this time, the holding part As the guide member rotates due to the upward force exerted on the forward feed roller, an upward force acts on the receiving portion of the guide member that supports the other end of the forward feed roller, thereby causing the forward feed roller to move upward while maintaining a horizontal state. Since the paper is lifted up, the paper feeding pressure in the longitudinal direction of the forward feed roller is applied evenly on the left and right sides, making it possible to prevent skew feeding.

(F) Embodiments Next, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 2 is a schematic diagram of a copy paper equipped with a paper feeder, and a stack bypass mechanism, indicated as a whole by number 1, is provided on the right side of the copy paper in the drawing. A paper holder 2 for placing the copy paper P, a limit switch 3 provided at the bottom of the paper holder 2, and a limit switch 3 provided at the upper part of the paper holder 2 in order along the paper transport direction to place the copy paper P. The guide member 4 rotates in a direction opposite to the copy paper pressing direction (clockwise in the figure) by contacting the guide member 4.
The guide member is movable up and down along the direction of a long hole 6 provided in the side plate of the paper feed section, and as the guide member rotates, its shaft is lifted upward, and the limit switch 3 It consists of a forward feed roller 5 that starts rotating upon detection of the leading edge and conveys the copy paper P to the leading end of the paper holder 2, and a paper feed roller 7 provided at the leading end of the paper holder 2. The copy paper P waits in contact with the paper feed roller 7 until copying is started by pressing a copy start button (not shown). A friction pad 8 for preventing double feeding is attached to the lower part of the paper feed roller 7 by a biasing means 9 such as a spring.
It is configured to be pressed into contact with the paper feed roller 7. The copy paper P transported from the stack bypass mechanism 1 into the copying machine by the paper feed roller 7 passes through a transport path formed by upper and lower guide plates 10, 10, and passes through a transport path provided upstream of the registration roller 12 in the copy paper transport direction. Limit switch 11 for detecting the leading edge of copied paper
After a predetermined period of time has elapsed, the conveyance of the copy paper P is temporarily stopped by the registration rollers 12, and then the copy paper P is conveyed to correct the oblique feeding of the copy paper P and to maintain timing with the exposure system.
The copy paper conveyed by the registration rollers 12 passes through a conveyance path formed by the upper and lower guide plates 13, and is conveyed to the transfer section T in order to transfer the toner image formed on the photosensitive drum 14 onto the copy paper P. Ru.

Further, a copy paper supply cassette 15 is attached to a cassette receiving portion 16 in the lower part of the copying machine body. The copy paper supply cassette 15 has a paper loading plate 17.
A push-up plate 19 is provided that urges the paper loading plate 17 from below so that the upper end of the copy paper comes into contact with the paper feed roller 18. The paper feed roller 18 includes
A friction pad 20 is in contact with the lower part thereof, and the copy paper is fed one by one to the conveyance path. The copy paper supplied from the copy paper supply cassette 15 is conveyed to the transfer section T as shown by the dashed line.
That is, along the conveyance direction, a conveyance path 21, a conveyance roller 22, a lower roller 23 pressed against the conveyance roller 22 by a leaf spring 24, and a conveyance path 25 are provided, and the conveyance path 25 is formed by the upper and lower guide plates 10. It merges with the conveyance route.

Next, the stack bypass mechanism 1 will be explained in detail with reference to FIGS. 1 and 2. A notch 28 is provided at approximately the center of the paper tray 2 in a direction perpendicular to the conveyance direction.
is provided, and the convex portion 3 of the side end regulating plate 26 is provided in the notch 28.
0 is engaged and tightened with a stop spring 29. Therefore, the side edge regulating plate 26 is slidable along the notch 28, and by matching the notch 26a with the size indication, the vertical portion 26b standing perpendicularly from the side edge regulating plate 26 allows the copy paper to be removed. It regulates one end of P. By adjusting the side edge regulating plate 26 to a desired size, copy sheets of a desired size can be fed.
For example, for A6, align the notch 26a with the A6 position, and for A4, move the side end regulating plate 26 to the position indicated by the two-dot chain line to align the notch 26a with the A4 position. Further, the other end of the copy paper is regulated by a regulation part 31 that stands perpendicularly to the paper holder 2. In this stack bypass mechanism 1, the reference is on the regulating part 31 side, that is, one end reference, so first, the copy paper P
is brought into contact with the regulating portion 31, and then the side edge regulating plate 26 is slid to regulate the side edges of the copy paper P. Further, the paper holder 2 is provided with a foldable projecting portion 2a, and is rotatable about shafts 27, 27. Therefore, when the copy paper P is large in size, the projecting portion 2a is opened to support the rear end of the copy paper P. When the size is small, it is folded and the side end regulating plate 26 is configured to slide on it. Also, the paper holder 2 has side plates 35 and 3.
5 so as to be rotatable about a fulcrum 65. The shape of the downstream portion of the sheet tray 2 in the conveying direction will be described in detail later.

Next, the guide member 4 and forward feed roller 5 will be explained. The guide member 4 is stretched in a direction perpendicular to the conveying direction, and is provided with a shaft portion 34 rotatably disposed on the side plates 35, 35, and a copy paper insertion path between the guide member 4 and the paper holder 2. , and when a large number of copy papers P are inserted, the shaft part 3
A copy paper guide section 36 rotates around shaft 34, protrudes from the end of shaft section 34, and rotates around shaft 3 of forward feed roller 5.
A holding part 3 that presses one end of the drive side of 7 from above.
2, and a receiving portion 33 that supports the other end of the shaft 37 of the advance roller 5 from below. A guide member 4 is located upstream of the guide member 4 in the copy paper conveyance direction.
The forward feed roller 5 provided parallel to the side plate 3
A shaft 37 fitted into a long hole (constituting a guide means) provided in the shafts 5 and 35, a plurality of rollers 38 provided at predetermined positions on the shaft 37, and a main roller provided at one end of the shaft 37. It consists of a gear 39 that meshes with an idle gear 40 that is connected to a motor (not shown). Gear (constituting the driving member) 3
The shape of the long hole 6 is configured as shown in FIG. 4 so that the hole 9 is always in contact with the idle gear 40. The forward feed roller 5 rises upward as the copy paper P is inserted, and presses the copy paper P from above with its own weight (therefore, it is always urged downward). When the leading edge of the copy paper P is detected by the limit switch 3 (FIG. 2) provided on the downstream side of the guide member 4 in the transport direction, the main motor rotates, and the rotational driving force of the main motor is transmitted. As a result, the idle gear 40 rotates in the direction _R1 , and the gear 39 also follows the rotation, thereby assisting in the insertion of the copy paper P. Furthermore, when the gear 39 rotates in the direction R ₂ , the entire gear 39 tries to lift upward due to the rotational force, so one end of the drive side of the shaft 37 rises, but the guide member 4 Since the holding portion 32 presses down from above, the rising is prevented. Further, the rising force acting on the holding portion 32 at this time causes the guide member 4 to rotate around the shaft portion 34, and the receiving portion 33 also attempts to rotate upward due to the rotational force. A lifting force is applied to the other end of the shaft 37 on the opposite side to the driving side, whereby the forward feed roller 5 is lifted upward while maintaining the horizontal state. Therefore, the forward feed roller 5 presses the holding portion 32 of the guide member 4.
By the action of the and receiving part 33, no matter what size the copy paper P is, it is lifted evenly on the left and right sides.
As a result, pressure is applied evenly on the left and right sides, so when the copy paper P is set at a predetermined position on the paper holder 2, and/or when the copy paper P is fed from the paper holder 2 into the inside of the copying machine. Diagonal feed is prevented.

Next, the paper feed roller 7 will be described. The paper feeding roller 7 has a shaft 42 rotatably attached to the side plates 35, 35, and the above-described idle gear 40 is attached to the shaft 42 via a bearing 46 at one end thereof projecting from the side plates 35. Further, a drive gear 48 is provided on the shaft 42 via a clutch means 47, and when the copy start button is pressed, the clutch means 47 is in a connected state for a certain period of time, and the paper feed roller 7 is rotated. . The drive gear 48 is rotating in the opposite direction to the idle gear 40, ie, in the direction of _R3 . The paper feed roller 7 has a first paper feed roller 4.
3. A second paper feed roller 44 and a third paper feed roller 45 are provided. The second paper feed roller 44 is in contact with the friction pad 8 which is biased by a spring from below.
Double feeding of copy paper P is prevented. On the other hand, the first and third
Paper feed rollers 43 and 45 serve as auxiliary rollers during paper feeding. In other words, it is possible to feed normal copy paper only by rotating the second paper feed roller 44, but it is possible to feed paper by rotating the second paper feed roller 44, but it is possible to feed paper by rotating the second paper feed roller 44, but it is possible to feed paper by rotating the second paper feed roller 44, but with thick copy paper, second original paper, etc.
When paper with a high friction coefficient such as OHP paper is used, the frictional force between the paper and the friction pad 8 is often greater than the conveying force of the second paper feed roller 44, so the paper feed Defects may occur. Therefore, at both ends of the second paper feed roller 44,
By providing the third paper feed rollers 43 and 45, supplementary conveyance force is added to improve conveyance performance. Furthermore, recesses 60 and 61 are formed in the paper tray 2 below the first and third paper feed rollers 43 and 45, and the first and third paper feed rollers 43 and 45 are provided with recesses 60 and 61.
0, 61, and the copy paper P is inserted into the paper feed rollers 43, 44, 4 as shown by the dashed line.
5 and the paper holder 2. Therefore, the conveyance force is reliably transmitted to the copy paper P, and the first and third paper feed rollers 43, 4
5 does not come into contact with the recesses 60 and 61 of the paper tray 2, so the conveyance force is directly transferred to the paper feed rollers 43 and 5.
45 is slightly weakened compared to when it is in contact with the paper holder 2, and double feeding can be prevented.

The shape of the tip of the paper tray 2 will be described in detail with reference to FIGS. 3a and 3b. Paper tray 2
The leading end is inclined downward toward the downstream part in the conveying direction so that the copy paper P can be easily inserted, but it goes upward from the lower part of the forward feed roller 5 as a boundary and continues toward the downstream side. As you head towards it, you will see the first Yamagata section 5.
0, a valley portion 51, and a second chevron portion 52, which are successively inclined in a direction in which the gradient gradually increases in order to improve conveyance performance, and reach a portion where the paper feed roller 7 and the friction pad 8 come into contact. As is clear from FIG. 4, the slope from A ₁ , which is approximately directly below the forward feed roller 5, to the first chevron portion 50 is gentle, and the height is not very high. The slope leading to the chevron portion 52 is steep, and the point _A1 , which is approximately directly below the forward feed roller 5, and the point of the first chevron portion 50
It is configured such that the apex of the second chevron portion 52 is located at the position where it connects and extends from _A2 . However, when the number of copy sheets P fed from the stack bypass mechanism 1 is small, as shown in FIG. 3a, the forward feed roller 5
As the copy paper P 1 rotates, the copy paper P ₁ is conveyed, and even after passing the point A ₂ due to its waist, it does not fall into the valley portion 51 and continues to the top of the second chevron portion 52 as shown by the dashed line, and then passes through the first and second chevrons. It is supported by parts 50 and 52 and comes into contact with a predetermined position of paper feed roller 7, and conveyance is stopped. If the first chevron portion 50 is not present, the copy paper P may fall into the valley portion 51 and may not come into contact with the paper feed roller 7. On the other hand, when a large number of copy papers P ₂ are to be fed, the copy papers P ₂ are transported by the advance roller 5 as shown in FIG. 3b.
Due to its own weight, it falls into the valley 51, where the lowest layer of copy paper is stopped, and as it goes to the upper layer,
The uppermost layer is inclined in the direction of the paper feed roller 7.
When the paper feed roller 7 comes into contact with the paper feed roller 7 at a position not far above the area where the paper feed roller 7 and the friction pad 8 contact, the conveyance is stopped. Also, at this time, regardless of whether the amount of stacked copy paper P is a small number or a large number, the copy paper enters the waiting state with the copy paper in contact with the paper feed roller 7 at approximately the same position. Paper can be done well. Incidentally, according to experiments conducted by the applicant, the angle θ ₁ from the upstream side of the sheet tray 2 in the conveyance direction to the point A ₁ located approximately directly below the forward feed roller 5 in FIG. 4 is approximately 10°. Point of first chevron 50 from _A1
The angle θ ₂ from point A ₂ to the bottom of the valley portion 51 is approximately 10 degrees, the angle θ _{3 from the bottom of the valley portion 51 to the bottom of the valley portion 51 is approximately 7 degrees, and the angle θ 3 from} the bottom of the valley portion 51 to the second chevron portion 52 is approximately 10 degrees. When the angle θ ₄ up to the top edge was set to 25°, the copy paper P could be fed most smoothly.

The operation of the paper feeding device in the above configuration is as follows. First, when feeding paper from the stack bypass mechanism 1, insert the side edge regulating plate 26 along the notch 28 so that the notch 26a of the side edge regulating plate 26 matches the desired size marking marked on the paper receiving plate 2. Slide it and set the copy paper. Especially when you want to set large-sized copy paper, use the overhanging section 2a.
are rotated around shafts 27, 27 to open and assist in supporting the rear end of the copy paper. When setting the copy paper, before the copy paper reaches the guide member 4, it hits the limit switch 3, the main motor begins to rotate, the power is transmitted to the idle gear 40, and then the drive gear 39, which rotates the forward feed roller 5. Therefore, the copy paper guide portion 36 of the guide member 4
The copy paper that comes into contact with the advance roller 5 from the copy paper supply path formed between the copy paper tray 2 and the paper tray 2 can be smoothly conveyed to a predetermined position. Further, at this time, the drive gear 39 is rotated in the direction of arrow _R2 by the rotational drive force transmitted to the drive gear 39, and a force that tends to rise is exerted, so that the drive side end of the shaft 37 of the forward feed roller 5 tries to rise, and the holding part 32 of the guide member 4 tries to hold it down, so the rise is suppressed to some extent, and on the other hand, due to the force acting on the holding part 32,
Since the guide member 4 rotates around the shaft 34, the receiving portion 33 provided at the other end of the shaft 34 tends to rise, and the forward feed roller 5 is eventually moved upward while maintaining a substantially horizontal state. , it becomes easy to set copy paper in a predetermined position. Further, when setting a small number of copy sheets, the paper feed roller 7 is brought into contact with the first and second chevron portions 50 and 52 of the paper tray 2 at a predetermined position where it can be easily conveyed. When setting a large number of copies, the lower part of the copy paper comes into contact with the valley 51 and does not advance any further, and only the upper part of the copy paper is conveyed. When the paper is tilted and the uppermost layer is brought into contact with the paper feed roller 7 at a predetermined position where it can be easily conveyed, the main motor is stopped, and as a result, the advance roller 5 is also stopped.

Next, when the copy start button is pressed, the main motor starts rotating, and the paper feed roller 7
The drive gear 48 rotates in the direction of arrow _R3 , and as the clutch means 47 becomes connected, rotational driving force is transmitted to the first, second, and third paper feed rollers 43, 44, and 45, and the paper feed At the same time, the drive gear 39 of the forward feed roller 5 is set to the idle gear 40 at _R1.
As it rotates in the direction of , it rotates in the direction of R ₂ ,
It assists in feeding the copy paper from the paper tray 2 into the copying machine. At this time, the second paper feed roller 44
is in contact with a friction pad 8 which is biased by a spring from below, and double feeding is prevented, and the conveyance is assisted by the first and third paper feed rollers 43 and 45.
It assists in transporting types of paper with a high coefficient of friction.

When the copy paper continues to be fed, passes through the copy paper transport path formed by the upper and lower guide plates 10, and the leading edge of the copy paper contacts the limit switch 11 for a predetermined period of time, the clutch means 47 is disengaged and the drive gear is turned off. The rotational driving force of 48 is no longer transmitted to the paper feed roller 7, and the paper feed roller 7 stops. During this time, the leading edge of the copy paper is registered by the registration rollers 12, preventing skew feeding and timing with the exposure operation. Simultaneously with the stop of the paper feed roller 7, the registration roller 12 begins to rotate, and reaches the transfer portion T on the photosensitive drum through a conveyance path formed by the upper and lower guide plates 13.

On the other hand, when copy paper is supplied using the copy paper supply cassette 15, the procedure is as follows. That is, the copy paper placed on the paper loading plate 17 is brought into contact with the paper feed roller 18 by the push-up plate 19. By pressing the copy start button, the paper feed roller 18 is rotated and enters a paper feeding state. The copy paper fed out one by one from the copy paper supply cassette 15 to the conveyance path 21 is transferred to the conveyance roller 22 and the lower roller 2.
The sheet passes through the nip position No. 3, further passes through the conveyance path 25, merges into the conveyance path formed by the upper and lower guide plates 10, turns on the limit switch 11, and after a predetermined time elapses, stops the sheet feeding operation. Then, it is conveyed to the transfer section T via the registration rollers 12 and the upper and lower guide plates 13.

Although the shape of the guide member 4 is such that the holding part 32 is provided at one end of the shaft part 34 and the receiving part 33 is provided at the other end, it is possible to have a holding part and a receiving part at both ends of the shaft part 34, respectively. It may be hot.

In addition, the tip of the paper holder 2 has the shape described above,
That is, as long as it has the first and second chevron portions and a valley portion therebetween, it may have any shape from the first chevron portion 50 to the upstream portion. Further, the first chevron portion 50 may have a steep slope from the apex to the valley portion 51.

Further, in the above embodiment, first and third rollers for assisting paper feeding are provided on both sides of the second paper feeding roller 44 in contact with the friction pad 8.
Although the paper feed rollers 43 and 45 are provided, the present invention is not particularly limited thereto, and the paper feed assist rollers may be provided at any position as long as they are coaxial with the paper feed roller 7.

(G) Effects of the invention The above invention has the following excellent effects. In other words, in order to smoothly set paper sheets, the forward feed roller is rotated, but even if one end of the drive side of the shaft of the forward feed roller rises due to the transmission of the rotational driving force, the holding part that holds it down will not be able to guide it. Because it protrudes above the forward feed roller from the member, it acts in a direction that prevents it from rising, and at the same time, the shaft portion of the guide member rotates due to the force acting on the holding portion, and the forward feed roller moves from the other end of the guide member. The receiving part that protrudes downward rises and tries to push up the other end of the shaft of the advance roller on the side opposite to the drive side, so the advance roller rises while maintaining a substantially horizontal position, and the paper sheet In addition to facilitating the insertion of
Since the pressure of the forward feed roller is applied equally on both sides, the paper sheets will not be slanted when being transported when setting them in a specified position, or during auxiliary paper feeding when the paper is fed by operating the copy start button after being set. It is possible to prevent the paper from being fed, and in turn, it is possible to prevent troubles such as paper jams.

[Brief explanation of the drawing]

Figure 1 is a perspective view of the stack bypass mechanism, Figure 2 is a perspective view of the stack bypass mechanism;
The figure is a simplified vertical cross-sectional view of the copying machine showing the paper feed section, Figures 3a, b, and 4 are simplified vertical cross-sectional views around the tip of the paper tray, and Figure 5 is a simplified vertical cross-sectional view of the copying machine showing the paper feed section. 7 is a partial cross-sectional view of the paper roller 7. FIG. 4... Guide member, 5... Advance roller, 7...
... Paper feed roller, 32 ... Pressing section, 33 ... Receiving section, 37 ... Shaft, 39 ... Drive gear.

Claims (1)

[Scope of Claim for Utility Model Registration] A paper feed roller that feeds paper sheets into the machine, and an axis parallel to the axial direction of the paper feed roller located upstream of the paper feed roller in the conveyance direction of the paper sheets. There are multiple
and a forward feed roller supported so as to be movable up and down along a guide means provided on a side plate; and a forward feed roller provided on the forward feed roller shaft and driven by a driving force from a drive source to rotate the forward feed roller shaft. a driving member that acts to raise the sheet; , a guide member that rotates around a shaft in a direction opposite to the pressing direction that is constantly biased to assist in the insertion of paper sheets; A presser portion protruding upward from one end of the shaft of the feed roller on the drive member side, and a receiving portion protruding toward the bottom of at least the other end of the shaft of the forward feed roller on the side opposite to the drive member side. A paper feeding device comprising: