JPH0445019A - sheet feeding device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a detachable sheet feeding device used in an image forming apparatus such as a copying machine or a laser beam printer.

(0) Conventional technology Conventionally, in a sheet feeding device that sequentially feeds sheets stacked on a sheet stacking means (hereinafter referred to as a paper feeding tray) from the bottom, a paper feeder whose upper peripheral surface protrudes from the sheet stacking means Sheets are fed by a roller and a weight (hereinafter referred to as weight) that faces the paper feed roller and presses and biases the sheet, and the applicant of the present application has already proposed this in the specification of Tokushoku No. 1-91235. are doing.

In this sheet feeding device, the weight is supported by a support lever so that it can move in an arc near the vertical line passing through the paper feed roller, and the weight and support lever move onto the paper feed tray. The support lever rotates integrally around the center of rotation according to the amount of sheets loaded. Further, the weight has an eave portion extending toward the sheet replenishing side for guiding the sheets supplied to the paper feed tray downward, and an opening is formed by the eave portion and the paper feed tray.

(C) Problems to be Solved by the Invention However, in the above conventional example, the engagement portion between the support lever supporting the weight and the weight needs to align the weight with the top surface of the seat and make contact with it. , has a certain degree of freedom of rotation, and when the weight is placed in the uppermost position when replenishing sheets to the paper feed tray, the crest of the weight tends to lower, causing the sheet to be supplied and the crest to This caused poor sheet replenishment operability.

Accordingly, the present invention provides a sheet feeding device that improves the operability of sheet replenishment by controlling the posture of the weight in such a direction that the weight visor rises when the weight is moved to the uppermost position during sheet replenishment. The purpose is to provide the following.

(d) Means for Solving the Problems The present invention has been made in view of the above-mentioned circumstances. For example, as shown in FIGS. A loading means (6), a feeding rotary body (16) that feeds the sheets (S) on the sheet loading means (6) one by one from below, and the sheet loading means (6).
a weight (1) which is loaded on the top sheet (S) and presses the sheet (S) against the feeding rotary body (16);
9), and a pressure release means (22, 23) for releasing the pressure on the sheet (S) by the weight (19). The weight (
It is characterized by comprising an enlargement control means (4) for controlling the attitude of the weight (19) so that the opening on the sheet insertion side of 19) is opened and expanded.

(f) Effect Based on the above configuration, when the weight (19) for sheet pressing is moved to the pressure release position via the pressure release means (22, 23), the weight (19) is activated by the expansion control means (4). This causes the eaves to rotate in a direction in which it rises, that is, in a direction in which the opening on the sheet supply side opens and widens. As a result, during sheet replenishment, interference between the leading edge of the sheet and the canopy of the weight (19) is significantly reduced, and the operability of sheet replenishment is improved.

Note that the above-mentioned symbols in parentheses are shown for reference to the drawings, and do not limit the configuration of the present invention in any way.

(F) Embodiment Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1 to 11 regarding a sheet feeding device as an example of a sheet feeding device.

1 to 4, a sheet feeding device 1 is detachably attached to the side of a laser beam printer 2 serving as an image forming device, and a laser beam printer 2 is provided below the sheet feeding device 1. A cassette 3 is provided which is detachably attached to the cassette 3. A pair of guide rods (protrusions) 5a and 5b are fixedly installed along the left and right direction at the base end (left end in FIG. 1) of the sheet feeding device 1, and the guide rod 5a , 5b into positioning holes (as shown) drilled in the laser beam printer 2, the sheet feeding device 1 is positioned. At the tips of the guide rods 5a and 5b,
A groove is provided for locking the sheet feeding device 1 to the laser beam printer 2. Further, a manual paper feed port 2a for inserting a manual sheet is provided above the cassette 3 on the side surface of the laser beam printer 2.

The sheet feeding device 1 has a paper feed tray 6 for loading sheets S)-3 (see FIG. Regulation plates 7a and 7b are provided for regulation. These regulation plates 7a, 7b
A pair of racks 9 and 10 are slidably arranged below the paper feed tray 6 along the width direction, and the racks 9 and 10 are rotatably arranged on the back side of the paper feed tray 6. The racks 9 and 10 are respectively meshed with the provided nions 11, so that the racks 9 and 10 can move in the width direction in conjunction with each other.

The paper feed tray 6 is provided with a sheet presence/absence sensor 12 for detecting the presence or absence of sheets. It is composed of a sensor lever 13 that swings and a photointerrupter 15 that is turned on and off by the sensor lever 13. On the downstream side of the sensor 12, a paper feed roller 16 for feeding the sheets stacked on the paper feed tray 6 from below is rotatably mounted on a support shaft 17, and the upper circumferential surface thereof is It extends above the paper feed tray 6.

A weight 19 is disposed above the paper feed roller 16 to press and bias the sheet S against the paper feed roller 16 . Both ends of this weight 19 extend from arc-shaped elongated holes 20a and 21a bored in the side plates 20 and 21 of the sheet feeding device 1, and are respectively attached to the free ends of the support levers 22 and 23 with some play. . Support lever 22
．． The base of 23 is pivotally connected to the side plates 20, 21 by shafts 25, 26, respectively. Near the downstream side of the weight 19, a tip regulating member 27 for regulating the tip of the sheets stacked on the paper feed tray 6 is disposed, and the lower end thereof and the downstream end of the paper feed tray 6 are arranged at a predetermined distance. They are separated by a distance, and the sheet S can be fed from this separation section 27a. Further, the leading edge regulating member 27 has a rib 27b for reducing friction with the sheet and preventing the leading edge of the sheet from curling, and its ridge line is inclined by about 3 degrees toward the paper feed tray 6 side from the vertical line. ing.

A mounting base 29 is fixed to the lower surface side of the tip regulating member 27, and a separation pad 30 made of a high friction member is attached to the mounting base 29.
The separation pad 30 is spaced apart from the paper feed roller 16 by a predetermined distance and is inclined at a predetermined angle with respect to the sheet S direction. A visible sheet-like member 31 is disposed at a position facing the separation pad 30, and the sheet fed from the paper feed roller 16 is transferred to the separation pad 30.
0 to prevent double feeding of sheets S. A guide 32 for guiding the sheet S is disposed downstream of the separation pad 30, and downstream of this guide 32,
A conveyance roller pair 33 consisting of a drive roller 33a and a pinch roller 33b is provided. The separation pad 3o and the sheet-like member 31 are fixed to the same mounting base 29, and the mounting base 29 is removable downward.

A connector 35 is fixed on the downstream side of the pair of conveyance rollers 33, and this connector 35 is connected to a connector (not shown) disposed on the laser beam printer 2, and is connected to the laser beam printer 2 for sheet feeding. An electrical connection is made with the device 1. Whether or not the sheet feeding device 1 is connected to the laser beam printer 2 can be detected on the laser beam printer 2 side by shorting the two contacts on the connector 35.

FIG. 2 shows a state in which sheets S are loaded on the sheet feeding device 1. As shown in FIG. The sheets S are pressed against the paper feed roller 16 by the gravity acting on the weight 19 and the tension of tension springs 39a and 39b, which will be described later.As the paper feed roller 16 rotates, the sheets S are sequentially fed starting from the lowest sheet S. When the sheet S is present on the paper feed tray 6, the sensor lever 13 is rotated counterclockwise from the position shown in FIG. 1 to the position shown in FIG. Then, one end 13a of the rotated sensor lever 13 is connected to the photointerrupter 1.
5, the rotation of the sensor lever 13, that is, the presence of the seat S is detected.

3 and 4 show the state in which the weight 19 is released and pressed when 1140 of the sheet feeding device 1 is opened. In the figure, reference numeral 140 is rotatable around a hinge shaft 41 whose both ends are attached to side plates 20 and 21, and hooks 42a and 42b are provided on both sides of the lid 40.
The base of is fixed. The support levers (press release means) 22, 23 have locking members 43a, 43b fixed in the middle thereof, and mounting members 45a, 45b fixed to the side plates 20, 21, respectively, at both ends. The free end is biased in a downward direction by the aforementioned tension springs 39a and 39b which are stopped. Also,
Dowels 46a, 4 are located in the middle of the support levers 22,23.
6b are fixed respectively, and these dowels 46a, 46
b engages with the hooks 42a and 42b of 1I40 and is in a hanging position relationship.

Next, the drive system in this embodiment will be explained with reference to FIGS. 5, 6, and 7.

In the figure, a drive side plate 51 that serves as the base of the drive system is fixed to the side plate 21 via a plurality of columns, and a drive motor (pulse motor in this embodiment) 5 is attached to the drive side plate 51.
2 is fixed. The drive side plate 51 also functions as a heat sink for the drive motor 52. A mounting member 45b to which the base of the guide rod 5b is attached is fixed to the drive side plate 51, and by bringing the tip of the guide rod 5b into contact with the frame of the laser beam printer 2, the sheet feeding device 1 is activated. It's falling to earth.

"Drive transmission system from rwA motor 52 to paper feed roller 16" The output of the drive motor 52 is transmitted through a gear 53 on the output shaft, a gear 55, a second gear 56, and a gear 57 that are pivotally supported on the drive side plate 51.
and the gear 60 attached to the support shaft 17 via the one-way clutch 59, thereby driving the support shaft 17 and the paper feed roller 16 fixed thereto. The one-way clutch 59 locks when the drive motor 52 rotates in the direction of arrow 61 in FIG. The feed roller 16 is inserted so that it does not rotate idly and rotate the paper feed roller 16 when reversed in the direction of the arrow 62.

Note that the support shaft 17 is supported by the side plate 2 by a pair of bearings 17a.
0 and 21 so as to be rotatable.

r Drive transmission system from drive motor 52 to transport roller pair 33 From drive motor 52 to gear 60, front paper feed roller 16
Since the drive transmission system is the same as that of , the explanation thereof will be omitted. The transmission system from the gear 60 to the transport roller pair 33 is divided into two transmission systems.

The first system is a system in which driving force is transmitted from gear 63 meshing with gear 57 to gears 65, 66, 67 and a shaft 70 to which gear 67 is attached via a one-way clutch 69. Here, the one-way clutch 69 is
When the drive motor 52 rotates in the direction of the dashed arrow 62, the shaft 7o and the drive roller 33 fixed thereto are locked.
Rotate a counterclockwise in FIG. -70 above
is rotatably attached to the side plates 20 and 21 by a pair of bearings 71.

In the second system, transmission is performed from the side plate 20 of the through shaft 72 to which the gear 65 is fixed by a pin 72a.
The through shaft 72 has a bearing 73a on the side plate 20 and the drive side plate 51.
, 73b, and is rotatably supported via the side plate 20.
A gear 75 is fixed to the side end. Gear 75 is
It is connected to a gear 79 via gears 76 and 77 that are respectively supported by the side plate 20, and this gear 79 is attached to the shaft 70 via a one-way clutch 80. Here, the one-way clutch 80 is locked when the drive motor 52 rotates in the direction of the solid arrow 61, and rotates the drive roller 33a in the counterclockwise paper feeding direction in FIG.

The drive motor 5 is driven by the transmission system of the first and second systems.
The rotation direction of the drive roller 33a is always counterclockwise in FIG. 1, regardless of the rotation direction of the drive roller 33a.

The side plate 20.21 is on the same axis as the through shaft 72.
Torsion springs 81a and 81b are fitted onto the bosses 20b and 21b, respectively, which are formed as a part of the bosses 20b and 21b. One end of the torsion springs 81a, 81b presses each end 82a, 82b of the shaft 82 of the pinch roller 33b in the direction of the drive roller 33a, and the other end of the torsion spring 81a presses and biases the ends 82a, 82b of the shaft 82 of the pinch roller 33b.
and the torsion spring 81b.
In addition, the ends are respectively locked to dowels 21c provided on the side plate 21.

11 of the sheet feeding device 1 based on FIGS. 8 to 10.
The lock portion of No. 40 will be explained. In the figure, pins 83 are loosely engaged with the side plates 20.21 near the base of the lid 40, and are movable into and out of the inside of the sheet feeding bag M1 and have a locking step at the outer end. This pin 83 is urged inward by a leaf spring 85 whose base is fixed to the outer surface of the side plates 20, 21 with screws 85a. M
2O has a pair of arm members 86 fixed to both sides of its base.
is supported so as to be openable and closable by being attached to the hinge shaft 41, and a locking hole 87 formed in the lower end of the arm member 86 is provided when the lid 40 is opened as shown in FIG.
It is arranged at a position where it engages with the pin 83 at an opening angle of 25 to 30@).

In the sheet feeding device 1 configured as described above, when stacking sheets S on the paper feeding tray 6, first! 40
When it is lifted and rotated in the opening direction, the hooks 42a and 42b integrated with 1140 engage with the dowels 46a and 46b of the support lever 22.23, respectively, and the support lever 22
．． Lift up 23. As a result, the weight is 19! !
The weight 19 is raised in conjunction with the opening operation of the lid 40, and is also stopped at the position where the locking mechanism of the lid 40 stops the weight 1140.

Next, insert the sheet S while sliding it onto the paper feed tray 6 until the leading edge hits the leading edge regulating member 27. When the M2O is closed in this state, the weight 19, which descends in conjunction with this, moves the sheet S to the highest position. Riding on the upper seat S, the weight of the weight 19 itself and the tension springs 39a, 39b are
Due to the urging force, a pressing force acts in a direction to press the sheet S against the drive roller 33a. When the sheet S is stacked on the paper feed tray 6, the sensor lever 13 is pressed and rotated, and the light from the photointerrupter 15 is blocked by the other end 13a, thereby detecting the presence of the sheet.

Further, in response to a paper feed signal from the laser beam printer 2, a motor start signal is output from the control board 89, and the drive motor 52 starts rotating in the direction of an arrow 61 in FIG. As a result, the paper feed roller 16 rotates counterclockwise in FIG. The paper is separated and sent to the next pair of transport rollers 33.

Before the sheet S is sent to the pair of transport rollers 33 and its rear end has not passed the paper feed roller 16, the drive motor 52 rotates in the reverse direction in the direction of arrow 62 in FIG. By this rotation of the drive motor 52 in the direction of the arrow 62, only the pair of transport rollers 33 is rotationally driven in the paper feeding direction to further feed out the sheet S.
Rotates as a result of the movement of. Sheet S is transferred to the next conveyance roller (for example, the paper feed roller of laser beam printer 2)
The drive motor 52 continues to rotate until it is sufficiently pushed in and passes through the transport roller pair 33, and then the drive motor 52 stops.

By repeating the above operations, continuous paper feeding from the paper feeding tray 6 is performed. When the sheets S in the paper feed tray 6 are fed in order from the bottom, the remaining sheets S gradually descend due to the weight of the weight 19 and the biasing forces of the tension springs 39a and 39b. slides against the tip regulating member 27. However, as described above, since the ridgeline of the rib 27b of the tip regulating member 27 is inclined toward the sheet S side with respect to the vertical line, the tip of the sheet S is pressed against the tip regulating member 27 due to the effect of the sheet S, and the sheet The leading edge of the sheet S does not curl, and therefore, paper feeding failures due to curling of the leading edge of the sheet S do not occur.

As the sheet S decreases, the tension springs 39a, 39
As the length of b becomes smaller, the tension decreases, and as a result, the pressing force on the sheet S by the weight 19 decreases as the sheet S decreases. When the paper feeding progresses further and the final two sheets remain, the upper sheet S is prevented from being fed by the friction member 90 provided on the sheet contact surface side of the weight 19, and only the lower sheet S is fed. It will be done. final 2
When the sheet feeding is completed, the sheet presence/absence sensor 12 notifies the laser beam printer 2 of a sheet non-signal, and the sheet feeding operation is ended.

Next, the displacement of the posture of the weight 19 will be explained based on FIGS. 11 and 12. In the same figure, arcuate long holes 20a and 21 bored in the side plates 20 and 21 mentioned above.
Vertical wall portions 20b and 21b are formed at the upper position of the upstream (right side in the figure) edge of a, respectively. At both ends of the weight 19 there are support levers 22.2.
The locking portions 19a to which the locking portions 3 are locked are each integrally provided, and the portions of the locking portions 19a facing the side plates 20, 21a are formed into an angular shape. Above locking part 1
9a and vertical wall portions 20a, 21a, etc., the weight 19
An enlargement control means 4 for enlarging the opening is configured.

The aforementioned l! As the weight 19 rises in conjunction with the release of the locking portion 40, the locking portion 19a gradually engages the vertical wall portion 20.
b, 21b, the locking portion 19a and the weight 19 integrated therewith rotate in the direction of the arrow (counterclockwise in the figure) as shown in FIG. As a result, the canopy portion 19b of the weight 19, that is, the sheet S to be replenished.
The insertion guide portion is flipped up from the imaginary line position in FIG. 12 to the chain line position, and the sheet S can be easily inserted into the paper feed tray 6.

FIGS. 13 and 14 show a weight 19 according to a second embodiment of the present invention, and parts with the same reference numerals as those in the first embodiment have similar functions, and their explanation will be omitted.

A projection 19c is formed on the weight 19 at a position opposite to the eaves 19b. Dowels 91 fixed to the inner surfaces of the side plates 20 and 21 are disposed above the movement path of the protrusion 19c. Above protrusion 1
The enlargement control means 4 is constituted by the dowel 9c, the dowel 91, and the like.

When the weight 19 moves upward in conjunction with the aforementioned opening of the lid 40, the protrusion 19c of the weight 19 engages with the dowel 91, and the weight 19 rotates in the direction of the arrow shown in FIG. 14 (counterclockwise). do. As a result, the eaves portion 19b of the weight 19 is flipped upward from the imaginary line position shown in FIG. .

FIGS. 15 and 16 show a third embodiment of the present invention. In the figures, the same reference numerals as those in the embodiment have the same functions, and the explanation thereof will be omitted.

In the same figure, an inclined portion 86a is formed on the arm member 86 integral with 1140, and this inclined portion 86a is located within the circular arc-shaped elongated holes 20a and 21a when the arm member 86 is rotated. A locking portion 19a integrated with the weight 19 and the inclined portion 86a
The enlargement control means 4 is constituted by the above.

! ! 40 is released and the weight 19 moves upward, the locking part 19a engages with the inclined part 86a of the arm member 86, as shown in FIG.
rotates counterclockwise in the figure, as shown in FIG. As a result, the eaves portion 19b of the weight 19 is flipped upward, and the sheet S can be easily inserted into the paper feed tray 6.

FIGS. 17 and 18 show a fourth embodiment of the present invention. In the figures, the same reference numerals as those in the first embodiment function in the same manner, and a description thereof will be omitted.

In this embodiment, the elongated hole 92 bored in the side plate 20 is composed of a vertical portion and an inclined portion 92a that is continuous with the vertical portion and is inclined toward the paper feed side. A long hole similar to the long hole 92 described above is formed. weight 1
A pair of protrusions 93.95 are provided on the upper and lower sides of both sides of the plate 9, and these protrusions 93.95 are connected to the side plates 20.
．． By inserting them into the long holes 92 of 21, they are guided to be vertically movable.

On the outside of the side plate 20, the base of an arm (pressure release means) 97 whose free end is inclined downward is pivotally mounted by a support shaft 96, and the free end of this arm 97 is connected to the projection 93.
95 with some play so that it can be rotated within an appropriate range. Further, an eccentric cam 100 is arranged on the side plate 20 at a position where it can engage with the arm 97, and is rotatably mounted on the side plate 20 by a support shaft 99. In addition, the spindle 99 has a manual knob 1.
01 is integrally provided. A similar arm 97, eccentric cam 100, etc. are provided on the other side plate 21 as well. The long hole 92 above. The enlargement control means 4 is constituted by the protrusions 93, 95 and the like.

In the above configuration, as shown in FIG.
When the knob 101 is operated with the upper seat S empty, the eccentric cam 100 whose small diameter portion faces the arm 97 gradually pushes up the arm 97 to a position toward the large diameter portion. Weight 1 with rotation of 97
9 rises along the elongated hole 92, the eccentric cam 100 rotates approximately 180 degrees, and as the upper protrusion 93 rises within the inclined part 92a of the elongated hole 92, the support shaft 17 moves to the first position.
As shown in Figure 8, the eaves portion rotates in the upward direction.

In this way, the weight 19 is raised and the inclined part 92
By tilting along a, the sheet S can be easily inserted into the paper feed tray 6.

FIGS. 19 and 20 show essential parts of a fifth embodiment of the present invention.

In the figure, reference numeral 102 indicates the center of gravity of the weight 19, and this center of gravity 102 is located between the weight 19 and the support lever 22.
It is eccentric to the paper feeding side with respect to the engaging part. Therefore, a moment acting on the weight 19 causes it to rotate in the direction indicated by the arrow (clockwise in the figure). The expansion control means 4 is constituted by the above-mentioned eccentric shape of the locking portion 19a and the weight 19. Due to the moment action caused by the deviation of the center of gravity of the weight 19, the eave portion 19b of the weight 19 is constantly flipped upward within the range allowed by the play of the engaging portion, causing the weight 19 to rise. The sheet S can be easily inserted in this state.

(G) As described in detail, according to the present invention, sheets are formed by the paper feed tray, which is a sheet loading platform, and the weight in conjunction with the pressure release operation of the weight that presses and biases the sheet. By rotating or tilting the weight so as to widen the opening on the side in the insertion direction, interference between the leading edge of the sheet and the weight when inserting the sheet into the paper feed tray is prevented. The operability of sheet replenishment can be significantly improved.

[Brief explanation of drawings]

FIG. 1 is a vertical side view of a sheet feeding device showing a first embodiment of the present invention, FIG. 2 is a vertical side view of the sheet feeding device loaded with sheets, and FIG. 3 is a side view of the same. Figure 4 is a longitudinal side view of the sheet feeding device with the lid open;
The figure is a plan view of the sheet feeding device, Fig. 6 is a side view of the drive side, Fig. 7 is a plan view of the drive system, Fig. 8 is a side view of the lid lock, and Fig. 9 is an operational view. , FIG. 10 is a front view of the main part of FIG. 8, FIGS. 11 and 12 are side views of the weight part showing the rotating state of the weight, and FIGS. 13 and 14 are views of the main part of the present invention. FIGS. 15 and 16 are side views of the weight part showing the second embodiment of the present invention, FIGS. 17 and 18 are side views of the weight part showing the third embodiment of the present invention, and FIGS. FIGS. 19 and 20 are side views of the weight part showing the fifth embodiment of the present invention. FIGS. S... Sheet 1... Sheet feeding device 2...
Image forming device (laser beam printer) 4...
- Opening enlargement control means 6...Paper feed tray (sheet stacking means) 16...Paper feed roller (feeding rotary body) 19th...Weight (weight) 19a-locking part,
19c...Protrusion portion 20a, 21a...Circular long hole 20b, 21b--Vertical wall portion 22.23-
・・Support lever (pressure release means) 40---@
86a inclined part 91-... dowel, 92... long hole
92a... Inclined part 97... Arm (pressure release means)

Claims (1)

[Claims] 1. A sheet stacking means for stacking a plurality of sheets, a feeding rotary member for feeding the sheets on the sheet stacking means one by one from below, and a sheet stacking means for stacking sheets on the sheet stacking means. A sheet feeding device comprising: a weight that presses the uppermost sheet to press the sheet against the feeding rotary body; and a pressure release means that releases the pressure on the sheet by the weight. A sheet feeding apparatus comprising an enlargement control means for controlling the attitude of the weight so that an opening on the sheet insertion side of the weight opens and expands in conjunction with a pressure release operation for the sheet.