JPH05132172A - Paper feed cassette for paper feeder - Google Patents

Abstract

PURPOSE:To eliminate the eccentric contact of a friction pad with a feed roller, and ensure the prevention of the feed of superposed sheets. CONSTITUTION:A slit 39 is formed in a pad holder 38 to fasten a friction pad 40, and an axis section 33f is provided at a leaf spring 33. Also, a guide groove 34 is formed on a cassette case 30 and a spring 37 is housed in the guide groove 34. Then, the pad holder 38 is inserted in the groove 34, and the axis section 33f is inserted in the slit 39. The pad holder 38 is so mounted on a guide section 32 as to be capable of free turn about the axis section 33f. When the friction pad 40 is pressed against a feed roller 18, the pad holder 38 is turned to keep the friction pad 40 fit to the surface of the feed roller 18, thereby maintaining line contact state without any eccentric contact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a printer, a copying machine,
The present invention can be applied to a recording device that records on a sheet by printing, transferring, printing, etc., such as a facsimile and a printing machine. In particular, in such a recording apparatus, it can be applied to a sheet feeding apparatus that rotates a feed roller to feed out a sheet, sequentially separates the sheets one by one, and feeds the sheet to a recording apparatus main body. More specifically, the present invention relates to a sheet feeding cassette that stacks and stores sheets in such a sheet feeding device.

[0002]

2. Description of the Related Art Conventionally, for example, in a paper feeder, a friction pad is fixed to a pad holder, and the pad holder is slidably supported by a guide member and urged by a spring to press the friction pad against a feed roller. It was composed. Then, at the time of sheet feeding, the feed roller is rotated to feed out the sheets in the sheet feeding cassette, and the sheets are sequentially fed to the recording apparatus main body one by one while preventing the double feeding by the friction pad.

[0003]

However, in this conventional sheet feeding device, since the pad holder is only slidably supported, when the friction pad is pressed against the feed roller, the friction pad moves the feed roller. On the other hand, it tends to be a one-sided contact state, so that it is not possible to reliably prevent the double feeding of the sheets at the time of sheet feeding.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to prevent the above-mentioned one-sided contact of the friction pad and reliably prevent the double feeding of the sheets.

[0005]

Therefore, according to the invention described in claim 1, for example, as shown in the following embodiments, a friction pad 40 pressed against the feed roller 18 is fixed to a pad holder 38, and the pad holder is fixed. In the paper feeding cassette 20 of the paper feeding device 17 in which 38 is attached to the holder holding portion 31 and is urged by the spring 37 to slidably support, the pad holder 38 and the holder holding portion 31.
Of the long holes 3 in one of the pad holders 38, for example.
9 is provided, and on the other hand, for example, the holder holding portion 31 is provided with a shaft portion 33f which is inserted into the long hole 39 thereof.

The invention described in claim 2 is, for example, as shown in the following illustrated embodiment, the sheet feeding device 1 described in claim 1.
In the paper feed cassette 20 of No. 7, the pad holder 38
The long hole 39 is provided in the holder holding portion 31.
And a guide portion 3 for guiding the sliding of the pad holder 38.
2 and an elastic member such as a leaf spring 33 attached to the guide portion 32, and the shaft portion 33f is provided on the elastic member.

The invention described in claim 3 is, for example, as shown in the following illustrated embodiment, the sheet feeding device 1 described in claim 2.
In the paper feeding cassette 20 of No. 7, the tip 3 of the elastic member
3c is provided with the shaft portion 33f, and the base end 33a is provided with the claw portion 33b.
Is provided, and the base end 33a is provided with the engaging hole 3 of the guide portion 32.
It is characterized in that the claw portion 33b is engaged with the guide member 6 to be locked, and the elastic member is attached to the guide portion 32.

The invention described in claim 4 is, for example, as shown in the following illustrated embodiment, the sheet feeding device 1 described in claim 2.
The sheet feeding cassette 20 of No. 7 is characterized in that the guide portion 32 is integrally formed with a cassette case 30 for storing the sheet S.

The invention described in claim 5 is, for example, as shown in the following illustrated embodiment, the sheet feeding device 1 described in claim 4.
In the paper feeding cassette 20 of No. 7, the cassette case 3
0 is provided with an upward guide groove 34 to integrally form the guide portion 32, and the spring 37 is formed in the guide groove 34.
After accommodating, the pad holder 38 is inserted, and the shaft portion 33f of the elastic member is inserted into the long hole 39 thereof.

[0010]

In the invention described in claim 1, when the friction pad 40 is pressed against the feed roller 18,
The pad holder 38 is rotated around the shaft 33f to bring the friction pad 40 into line contact with the feed roller 18.

In the second aspect of the invention, when the pad holder 38 is replaced, the shaft portion 33f of the elastic member is removed from the long hole 39 of the pad holder 38.

According to the third aspect of the invention, the guide portion 32 is provided.
When this elastic member is attached to the claw portion 3 by fitting the base end 33a of the elastic member into the engaging hole 36 of the guide portion 32.
Lock 3b.

When the pad holder 38 is attached to the guide portion 32, the spring 37 is housed in the guide groove 34 from above and then the pad holder 38 is inserted to insert the pad holder 38 into the elongated hole. The shaft portion 33f of the elastic member is inserted through 39.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 3 is a schematic view of the entire internal structure of a laser printer including a paper feed cassette according to an embodiment of the present invention. Reference numeral 10 in the figure denotes the apparatus main body. A belt-shaped photosensitive body 11 is provided in the apparatus main body 10 substantially at the center. Around the photoconductor 11, a charging device 12, a developing device 13, a transfer device 14, and a cleaning device 15 are arranged in this order in the driving direction indicated by the arrow in the figure. An optical writer 16 is arranged above the charger 12 and the cleaner 15. Further, on the lower side of the apparatus main body 10, the paper feeding device 1
Place 7. The sheet feeding device 17 is provided with a feed roller 18 below the developing device 13 and is provided with a sheet feeding cassette 20.
Is detachably attached. Sheets S are stacked and stored in the paper feed cassette 20.

Then, the feed roller 18 is rotated and the sheet S is sent out from the inside of the paper feed cassette 20 in the direction of arrow A in FIG. Then, the registration roller pair 22 conveys it to the lower side of the photoconductor 11 at a timing. The photoconductor 11 is driven in the clockwise direction shown by the arrow, and at that time, the surface of the photoconductor 11 is uniformly charged by the charger 12. Then, the surface of the photoconductor 11 is irradiated with laser light from the optical writer 16 to form an electrostatic latent image. This latent image
When it passes through the developing device 13, it is visualized by toner. Then, this visible image is transferred by the transfer device 14 onto the upper surface of the sheet S conveyed to the lower side of the photoconductor 11. After the transfer, the sheet S is guided by the conveyance guide 23 and conveyed to the fixing device 24, and the visible image is fixed by the fixing device 24. Then, the sheet S exiting the fixing device 24 is further conveyed by the sheet ejection roller 25 and ejected in the arrow B direction or the C direction. On the other hand, the photoreceptor 11 after the transfer of the visible image is cleaned by the cleaning device 15 to remove the residual toner, and then discharged by the discharging device 26.

By the way, the paper feed cassette 20 described above is
As shown in FIG. 3, a box-shaped cassette case 30 accommodating sheets S is provided inside, and a holder holding portion 31 is provided on the rear end side of the cassette case 30 in the insertion direction (direction of arrow D). As shown in an enlarged view in FIGS. 1 and 2, the holder holding portion 31 has a guide portion 32 integrally formed by projecting a part from the center to the outside, and a leaf spring (elastic member) attached to the guide portion 32. And 33.

The guide portion 32 has a narrow guide groove 34 opened upward, and a cylindrical groove portion 34a is formed in the center of the guide groove 34 in the depth direction. Also, the cylindrical groove portion 3
The elongated hole 35 is penetrated from the outside at a right angle to the depth direction of 4a.
A convex portion 32a is formed outward from the lower side of the elongated hole 35, and a narrow engaging hole 36 is formed in the convex portion 32a in the height direction.

A spring 37 is inserted into the guide groove 34 along the cylindrical groove 34a from the upper side of the guide groove 34 and accommodated therein, and then a pad holder 38 is further inserted and arranged on the spring 37. The pad holder 38 has a vertical plate portion 38a and a holding plate portion 38b which is provided from the upper end of the vertical plate portion 38a with a slight inclination with respect to the vertical plate portion 38a, and is formed into a substantially T-shape as a whole. Further, the width dimension d of the vertical plate portion 38 a is smaller than the groove length of the guide groove 34 by 1 to 2 mm, and the thickness dimension t is 0.02 smaller than the groove width of the guide groove 34.
It is formed to be 0.5 mm smaller. And the vertical plate portion 38
A slot 39 is provided in a, and a friction pad 40 is fixed to the upper surface of the holding plate portion 38b by adhesion or the like.

As shown in FIG. 2, the leaf springs 33 project outwardly from both side edges of the base end 33a of the leaf spring 33, and the claw portions 3 are formed.
3b is provided, and a bent portion 33d bent in a U shape is provided at the tip 33c. Further, an upper edge of the tip 33c is bent upward to provide a grip portion 33e, and a small columnar shaft portion 33f is provided on one surface of the bent portion 33d. Then, the leaf spring 33 has the base end 33a at the engagement hole 3
6, and the claw portion 33b is locked to the convex portion 32a and attached to the guide portion 32. Thus, the leaf spring 33 is prevented from falling off the guide portion 32.

Then, the pad holder 38 is pushed down against the spring 37, and when the long holes 35 and 39 are aligned, the shaft portion 33f of the leaf spring 33 is inserted into the long holes 35 and 39. Then, the pad holder 38 is attached to the guide groove 34.
It is slidable along and is attached to the guide portion 32 so as to be rotatable around the shaft portion 33f.

The above-mentioned paper feed cassette 20 is shown in FIG.
As shown in FIG. 5, the feed roller 18 hits the friction pad 40 and pushes it down when it is attached to the apparatus body 10. Then, the spring 37 urges the friction pad 40 against the feed roller 18 lightly. At that time, the pad holder 38 is rotated to make the friction pad 40 conform to the surface of the feed roller 18 and make a line contact without one-sided contact. Then, the bottom plate 44 on which the sheet S is placed is pushed up by a known means to press the uppermost sheet S against the feed roller 18. Then, the apparatus main body 10 is operated, the feed roller 18 is rotated, and the sheet S is fed out from the cassette case 30. The friction pad 40 prevents double feeding, and the sheets S are automatically transferred to the registration rollers 22 one by one. And send it out.

When the pad holder 38 is replaced due to abrasion of the friction pad 40 or the like, the paper feed cassette 20 is pulled out from the apparatus main body 10 and then the grip portion 33e.
1, the plate spring 33 is bent in the direction of arrow E in FIG. 1 to expose the shaft portion 33f from the elongated hole 39 of the pad holder 38, and then the pad holder 38 is taken out from the guide groove 34. After this removal, the leaf spring 33 is returned to the bent portion 33d.
Is again inserted into the long hole 35, and the shaft portion 33f prevents the spring 37 from coming out of the cylindrical groove portion 34a. And
The plate spring 33 is bent again to move the shaft portion 33f out of the guide groove 34, and then the vertical plate portion 38 of the new pad holder 38 is formed.
Insert a into the guide groove 34. Then, the shaft portion 33f is again inserted into the long hole 39 of the pad holder 38, and the new pad holder 38 is attached to the holder holding portion 31. After this attachment, the paper feed cassette 20 is inserted into the apparatus main body 10.

[0023]

Therefore, according to the first aspect of the present invention, not only the pad holder is slidably attached to the holder holding portion but also the holder is rotatably attached to the shaft portion. When the pad is pressed, the friction pad can be brought into line contact with the feed roller without being hit against the feed roller, and thus it is possible to reliably prevent double feeding of the sheets.

According to the second aspect of the present invention, the pad holder is provided with the elongated hole, the elastic member is attached to the guide portion for guiding the sliding of the pad holder, and the elastic member is provided with the shaft portion. It becomes easy to engage and disengage the shaft portion with respect to the elongated hole, whereby the friction pad can be easily replaced without using a tool.

According to the third aspect of the present invention, the shaft portion is provided at the tip of the elastic member, the claw portion is provided at the base end, and the base end is fitted into the engaging hole of the guide portion, Since the claw portion is locked in the engaging hole and the elastic member is attached to the guide portion, it is possible to easily attach and detach such an elastic member to and from the guide portion.

According to the fourth aspect of the present invention, since the above-mentioned guide portion is formed integrally with the cassette case for accommodating the sheet, the structure can be simplified and the number of parts can be reduced accordingly.

According to the fifth aspect of the present invention, the cassette case is provided with the upward guide groove, the spring is accommodated in the guide groove, the pad holder is inserted, and the shaft portion of the elastic member is inserted into the elongated hole. By inserting the pad holder, the pad holder can be easily attached to the guide portion from one direction.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an enlarged main part of a paper feed cassette according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the vicinity of a guide portion of the paper feed cassette.

FIG. 3 is an overall schematic configuration diagram showing an internal mechanism of a laser printer including this paper feed cassette.

[Explanation of symbols]

 17 Paper Feeding Device 18 Feed Roller 20 Paper Feed Cassette 30 Cassette Case 31 Holder Holding Part 32 Guide Part 33 Leaf Spring (Elastic Member) 33a Leaf Spring Base End 33b Claw Part 33c Tip 33f Shaft Part 34 Guide Groove 36 Guide Part 36 Dowel 37 Spring 38 Bad holder 39 Long hole for pad holder 40 Friction pad S seat

Claims (5)

[Claims] 1. A paper feed cassette of a paper feed device, wherein a friction pad pressed against a feed roller is fixed to a pad holder, the pad holder is attached to a holder holding part, and is biased by a spring to slidably support the paper feed cassette. A sheet feeding cassette of a sheet feeding device, wherein one of the pad holder and the holder holding portion is provided with a long hole, and the other is provided with a shaft portion which is inserted into the long hole. 2. The pad holder is provided with an elongated hole, and the holder holding portion is provided with a guide portion for guiding sliding of the pad holder and an elastic member attached to the guide portion, and the elastic member is provided with the above-mentioned member. The sheet feeding cassette of the sheet feeding device according to claim 1, further comprising a shaft portion. 3. The shaft portion is provided at the tip of the elastic member,
The paper feed according to claim 2, wherein a claw portion is provided at a base end, the base end is fitted into an engagement hole of the guide portion to lock the claw portion, and the elastic member is attached to the guide portion. Paper cassette of the device. 4. The sheet feeding cassette of the sheet feeding device according to claim 2, wherein the guide portion is integrally formed with a cassette case for accommodating sheets. 5. The cassette case is provided with an upward guide groove to integrally form the guide portion, the spring is housed in the guide groove, and then the pad holder is inserted, and the elastic hole is inserted into the elongated hole. The sheet feeding cassette of the sheet feeding device according to claim 4, wherein the shaft portion of the member is inserted.