JPH0632488A - Paper feeder structure - Google Patents

Abstract

PURPOSE:To carry out the course reversing of paper sheet feeding smoothly and easily without generating a jamming. CONSTITUTION:A C-shape conveying passage 25 to reverse the course of paper sheets delivered from a paper sheet cassette and to feed them to a register roller couple is composed of a C-shape guide plate 251 with the C-shape section, which has the lateral size almost same as the width of the feeding paper sheets, and in this C-shape guide plate 251, both side ends 251a' at the upstream end are formed by providing difference in level at the outer side in the vertical direction to the central part 251b, and by eliminating the difference in level at the downstream end.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to the structure of a sheet feeding section for feeding sheets for image transfer to an image forming apparatus section in an image forming apparatus or a facsimile.

[0002]

2. Description of the Related Art In an image forming apparatus or the like, mainly from the viewpoint of downsizing of the apparatus, a sheet fed from a sheet feeding cassette by a sheet feeding roller is converted to a desired direction and fed to a pair of registration rollers. Therefore, there is known one that employs a paper feeding unit that reverses the transport direction. For example, conventionally, a curved body having a required shape and composed of an inner guide plate and an outer guide plate which are opposed to each other at a predetermined interval are widely used.

[0003]

According to this type of sheet feeding unit structure, the structure is complicated, and the leading end of the sheet fed from the cassette is bent to wind around the sheet feeding roller to cause a jam, or , There is a possibility that it may come into contact with the entrance of the paper feed section for reversing the direction and cause a jam, etc.
In that case, the jam clearance work was not easy. Further, the bent position of the sheet due to the direction reversal is not stable, which may cause the nipping between the pair of registration rollers to not be properly performed.

Further, when the trailing edge of the sheet is fed out from the sheet feeding cassette due to the sheet restoring force generated by bending the sheet by reversing the direction, the sheet is struck against the member on the downstream side, and this impact causes abnormal noise. It was

The present invention has been made in view of the above,
An object of the present invention is to provide a paper feed unit structure that smoothly and easily feeds and reverses the direction of fed paper, facilitates jam occurrence prevention and jam treatment, and prevents abnormal noise. .

[0006]

The invention according to claim 1 is
In a paper feed unit for reversing the direction of a sheet fed from an upstream side to feed the sheet to a downstream side, the sheet feeding section has a C-shaped cross section having a lateral dimension substantially the same as the width of the fed sheet. The reversal guide portion is formed such that both end portions of the upstream end thereof have a step outward in the vertical direction with respect to the central portion, and the step is eliminated at the downstream end. .

According to a second aspect of the present invention, in a paper feeding section for reversing the direction of the paper fed from the upstream side and feeding the paper to the downstream side, the paper feeding section is provided with a reversing guide section having a C-shaped cross section. And both sides thereof have a rotatable shaft support structure.

According to a third aspect of the present invention, in the paper feed unit for reversing the direction of the paper fed from the upstream side and feeding the paper to the downstream side, the paper feeding unit has substantially the same width as the fed paper. A reverse guide portion having a C-shaped cross section and a roller that is in the opening surface of the reverse guide portion, is close to the upstream end side of the reverse guide portion, and is axially supported in the lateral direction. This roller is used to assist the smooth reversal of the paper.

According to a fourth aspect of the present invention, in a paper feeding unit for reversing the direction of the paper fed from the upstream cassette and feeding the paper to the downstream side, the paper feeding unit is a reverse guide unit having a C-shaped cross section. The inversion guide plate is provided with an elastic member attached to the inner wall in the vicinity of the upstream end of the inversion guide plate with the tip thereof being floated toward the upstream side.

According to a fifth aspect of the present invention, the cassette is mounted on the main body of the apparatus, and is located on the upper surface of the cassette.
In a paper feed unit having a paper feed roller that feeds the paper loaded in the cassette to a downstream guide, the downstream side of the paper feed roller downstream from a position near the paper feed roller in a direction orthogonal to the paper feed direction. A guide member, which is between the side guides and whose height is lower than the sheet contact position of the paper feed roller, is arranged in the apparatus main body.

[0011]

According to the first aspect of the present invention, when the sheet is fed from the upstream side to the sheet feeding section, the central portion in the width direction of the fed sheet comes into contact with the upstream end portion of the reversing guide, while the feeding sheet is fed. Both widthwise edge portions of the fed sheet are guided into the reversing guide portion by the stepped side end portions of the reversing guide portion without contacting the upstream end. Edge portions on both sides of the sheet gradually slide in contact with the reversing guide surface at curved portions in the reversing guide portion, and smooth reversal can be performed. Then, when passing through the inside of the reversing guide portion and reversing the direction from the downstream end and being carried out, the paper is flush.

Further, according to the second aspect of the present invention, when the reversing guide is arranged in the sheet feeding path, the reversing guide is rotated by the shaft supporting structure on both side surfaces thereof, so that the inside of the reversing guide is Opened from the upstream side and the downstream side, the jammed paper inside can be easily removed or cleaned.

Further, according to the third aspect of the invention, the leading end of the sheet is reversed in the conveying direction while sliding on the reversing guide surface of the reversing guide section, and the intermediate portion of the sheet is moved along with the reversing operation of the leading end of the sheet. A predetermined waist is formed on the paper by contacting the rollers. Further, even when guided by the guide surface at the upper end of the reversing guide portion, the tip of the paper is pressed against the guide surface side by the restoring force of the waist formed by the rollers, and it is smooth and smooth without being separated from the guide surface. It is reliably conveyed to the downstream end of the reversing guide section.

According to the fourth aspect of the present invention, the sheet fed from the upstream cassette is C at the reversing guide portion.
The sheet is bent into a letter shape, and the rear end portion of the sheet is urged against the inner wall of the upstream end of the reversing guide portion by the restoring force. When the trailing edge of the sheet moves from the cassette to the upstream end of the reversing guide section, the trailing edge of the sheet is struck against the inner wall of the upstream end of the reversing guide section through the elastic member, so that the shock is buffered and thereby the abnormal noise is generated. Occurrence is prevented.

According to the fifth aspect of the invention, the sheet fed from the cassette by the sheet feeding roller is forcibly guided to the downstream guide as it is by the guide member, so that the sheet is bent or the like. Also, this paper does not wind around the paper feed roller.

[0016]

21 is a perspective view showing the appearance of a facsimile equipped with an image forming apparatus to which the present invention is applied.

The facsimile shown in the figure has a well-known facsimile function and an image forming function for forming an image on a cut sheet type transfer paper, and forms an image of the received image on the transfer paper and outputs it. It is also possible to form an image on transfer paper and output it.

This facsimile has an apparatus main body 1, and the original main body 2 is formed on the upper right side of the apparatus main body 1,
An operation panel 3 is provided on the left side of the upper surface, and a telephone 4 is connected to the rear end of the upper surface. In addition to the ten-key pad, the operation panel 3 is provided with a setting key 3a for setting various functions and operation conditions necessary for facsimile transmission and image formation, and a display section 3b for displaying setting contents.

Further, inside the apparatus main body 1, a unitized document reading section and an image forming section having an image forming function are arranged. A part of the image forming unit is composed of an attachable / detachable image forming unit as will be described later, and the front door 8 of the apparatus main body 1 is opened to be attached / detached to / from the apparatus main body 1. ing.

On the left side surface of the apparatus main body 1, a document discharge tray 5 for discharging the document read by the document reading section,
A transfer paper discharge tray 6 is provided for discharging the transfer paper after the transfer in the image forming unit. Further, the paper feed cassette 7 is attached to the lower end of the apparatus main body 1 from the left side. From the paper feed cassette 7, a cut sheet type transfer paper of a standard size is fed to the image forming section.

The apparatus main body 1 is composed of a lower frame body and an upper frame body, as will be described later, and the upper frame body is rotatably attached to the lower frame body about the left end. On the other hand, on the right side surface of the apparatus main body 1, a lever 9 for unlocking the upper frame body and the lower frame body is provided, and by pushing the lever 9 upward, the upper frame body rotates counterclockwise. Then, the right side of the device body 1 is opened.

FIG. 3 is a perspective view of essential parts showing a state in which the upper frame body 10 and the lower frame body 11 of the apparatus body 1 are opened. Further, FIG. 4 is a perspective view of a main part in which an image forming unit, particularly a developing unit, is added in FIG.

The upper frame 10 is mainly made of resin and integrally molded to form a front side plate 101, a rear side plate 102 and both side plates 10.
Reinforcing plates 103 to 106 made of an iron plate or the like for reinforcing the connection between the first and second plates 102 and preventing the side plates 101 and 102 from being twisted.
Etc. The document reading unit 17 is attached to the upper left side of the upper frame 10, and the developing unit 12 is inserted into the apparatus main body 1 from the front plate 101 side inside the upper frame 10. As will be described later, the edge portions of the both side plates 101, 102 have a brim shape having a required width in the front-rear direction, and the brim-shaped portion suitably guides the insertion of the developing unit 12.

The reinforcing plate 103 has an L-shaped cross section as shown in FIG. The reinforcing plate 104 is made of resin or the like and also serves as a mounting plate for the side plates 101 and 102. The reinforcing plates 105 and 106 also serve as mounting plates for the optical unit 21 that constitutes a part of the image forming unit described later.
The reinforcing plate 105 also serves as an insertion guide plate for the developing unit 12. The position regulating member 107 regulates the descending position of the upper frame body 10 with respect to the lower frame body 11, and the lock member 108 is a mounting plate of the lever 9 and locks the upper frame body 10 to the lower frame body 11. It is a lock member. The position regulating member 107 and the lock member 1
The configuration and operation of 08 will be described later.

FIG. 5 is a perspective view of a main part showing the shape of the front side plate 101, FIG. 6 is a view showing a mounting structure between the front side plate 101, the rear side plate 102 and the reinforcing plate 103, (a) is a plan view,
(B) is a right side view.

As shown in FIG. 5, the front side plate 101 has a T-shaped cross section composed of a side plate portion 101a and a brim-shaped peripheral portion 101b provided at right angles on both sides of the edge of the side plate portion 101a. Similarly, the rear side plate 102 also has the side plate portion 102.
It has a T-shaped cross-section formed of a and a peripheral portion 102b.

On the other hand, the reinforcing plate 103, as shown in FIG. 6, is an upper plate portion 103 forming a part of the upper surface of the upper frame 10.
a, the right side plate portion 10 forming a part of the right side surface of the upper frame body 10
3b, the front side plate portion 1 which is a connecting portion between the side plate portion 101a of the front side plate 101 and the side plate portion 102a of the rear side plate 102.
03c and the rear plate portion 103d, and is formed by bending a single metal plate.

In the reinforcing plate 103, the front side plate portion 103c and the rear side plate portion 103d are respectively formed by the side plate portion 1 of the front side plate 101.
01a and the side plate portion 102a of the rear side plate 102, and both ends of the upper plate portion 103a and the right side plate portion 103a.
Both end portions of b are the peripheral portions 101b of the side plates 101 and 102,
It is attached to the front plate 101 and the rear plate 102 by being coupled to 102b. Thus, the front side plate 101 and the rear side plate 102 are integrally formed side plate portions 101a, 102.
Since the three surfaces consisting of a and the peripheral portions 101b and 102b on the upper surface side and the right side surface side are fixed to the reinforcing plate 103, deformation is not easily generated even against torsional stress.

Further, by providing the peripheral portions 101b and 102b, it is possible to smoothly attach and detach the developing unit 12. Particularly, by forming a taper diverging outward in the peripheral edge portion 101b and providing a mounting guide for the developing unit 12, the mounting / dismounting operation of the developing unit 12 can be performed more smoothly.

Further, the front side plate 101 and the rear side plate 102 are also reinforced by a document reading unit 17 attached to the upper frame 10. That is, FIG. 7 is a perspective view of the upper frame 10 as viewed from above the right side surface. The document reading unit 17 has mounting bosses 171 and 172 projecting from both side surfaces of the unit housing. ，
The part 172 is fitted into the mounting grooves 101c, 102c formed in the front side plate 101 and the rear side plate 102, and is fixed to the upper frame body 10 by fixing it from the outside of both side plates 101, 102 with screws or the like. It is like this. The document reading unit 17 is mounted on the front side plate 101 and the rear side plate 1.
By fixing the document reading unit 17 to the front plate 101 and the rear plate 102, the original reading unit 17 functions as a stay that supports between the front plate 101 and the rear plate 102, whereby the twisting prevention of the both side plates 101 and 102 is further strengthened.

As described above, since the front plate 101 and the rear plate 102, which are integrally molded of resin, are connected to each other at a plurality of opposing positions by the reinforcing plates 103 to 106 made of a plurality of metal plates, the upper frame is formed. The front side plate 101 is caused by the torsional stress generated by the vertical movement of the body 10 and the attachment / detachment of the developing unit 12, etc.
Also, the rear side plate 102 is not easily deformed.

Returning to FIG. 3, a rotating shaft 14 projecting outward is provided on both sides of the left end portion of the upper frame body 10 as a pair of mounting plates 13,
13 'are rotatably attached. On the other hand, at the left end of the lower frame body 11, a support plate 15 having a hole 151 is erected so as to overlap the mounting plates 13 and 13 '. The upper frame 10 has the rotating shaft 14 and the lower frame 11
It is attached to the lower frame 11 by penetrating the hole 151 of the support plate 15 and the spring 16.

The base end portion 16a of the spring 16 is brought into contact with the bent portion 152 of the support plate 15, while the tip end portion 16b is fixed to the both side plates 101 and 102 of the upper frame body 10 at appropriate positions. The upper frame body 10 is urged to rotate counterclockwise by a predetermined angle by the restoring force. Therefore, when the lock is released by operating the lever 9, the upper frame 10 is rotated counterclockwise by a predetermined amount by the urging force of the spring 16, and the apparatus body 1 is opened to a suitable state.

On the other hand, the apparatus main body 1 in the open state is closed and automatically locked by pushing down the right end of the upper frame body 10. That is, when the right end portion of the upper frame body 10 is pushed downward, the upper frame body 10 rotates clockwise around the rotation shaft 14, and when the right end portion of the upper frame body 10 descends to a predetermined position. , The position regulating member 1
The turning movement of the upper frame body 10 is restricted by 07, and the upper frame body 10 is locked to the lower frame body 11 by the lock member 107.

8 and 10 show the position regulating member 107.
8A shows the structure of the lock member 108 and FIG.
Is a right side view of the upper frame body 10, FIG. 8B is a partially enlarged view showing the shape of the recess of the position regulating member 107, and FIG. 10 is a front sectional view of the main part of the upper frame body 10. 9 is a lower frame body 11 showing a lock mechanism for the upper frame body 10 and the lower frame body 11.
FIG.

A recess 107a for restricting the lowering position of the upper frame 10 is formed at a proper position near the rear plate 102 on the lower side of the position restricting member 107. Recess 107a
As shown in FIG. 8 (b), a required narrow width portion 107c is formed following the tapered portion 107b, and an oval notch portion 107d having a predetermined depth is formed at the back of the tapered width portion 107b. is there.

Further, as shown in FIG. 10, an inclined portion bent outward by a predetermined angle is provided on the upper portion of the position regulating member 107. By bending the lower end side of the position restricting member 107 inward of the upper frame body 10, the upper frame body 10 is bent.
It is attached and fixed to.

The lock member 108 has connecting plates 108a whose both ends are bent in an L shape, and the engaging portions 10 are provided at both ends thereof.
8b and 108b 'are provided perpendicularly to the connecting plate 108a, and the front plate 101,
It is rotatably supported by the shaft 102. The abutting portion 10 is provided at a proper position of the base end portions of the engaging portions 108b and 108b '.
8 c and 108 c ′ are formed, and engaging claws 108 d and 108 d ′ that are provided in a protruding manner in the rotation direction are formed at appropriate positions on the tip end portions. Further, the lever 9 is attached at a predetermined position of the connecting plate 108a, for example, in the vicinity of the center slightly front side (see FIG. 3), and the lever 9 is attached downward between the lever 9 and the position regulating member 107. A biasing spring 20 is provided.

Further, as shown in FIG. 9, mounting plates 19 and 19 'are provided on the upper surface of the lower frame 11 at appropriate positions on both rear end portions. The mounting plate 19 'is a front mounting plate 1 which will be described later.
This mounting plate 19 'is formed by cutting one metal plate into a desired shape and bending it as shown in FIG.
A fitting portion 191 'that is fitted into the concave portion 107a is provided at an appropriate position on the tip of the. And the upper frame 10
Is rotated clockwise, and the fitting portion 191 'is fitted into the recess 107a of the position regulating member 107, whereby the closing operation of the upper frame 10 and the positional displacement in the front-rear direction are regulated. There is.

Since the shape of the cutout 107d is oval as described above, the recess 107 of the position regulating member 107 is formed.
Even when a is inclined with respect to the fitting portion 191 ', the fitting portion 1
91 'smoothly fits and surely contacts the contact surface of the cutout 107d, and the upper frame 10 is stopped at a predetermined lowered position.

If the concave portion 107a is provided with a small width portion 107c that regulates the lateral displacement of the upper frame body 10 and a cutout portion 107d that regulates the lowering movement,
The shape is not limited to that shown in FIG. For example, a rectangular long groove of a predetermined length having substantially the same width dimension as the narrow width portion 107c may be bored following the tapered portion 107c.

The position regulating member 107 may be provided on the lower frame 11 side, and the fitting portion 19 'may be provided on the upper frame 10 side.

An outer base plate 41 'and an inner base plate 42' are bent and provided at the lower end of the mounting plate 19 ', and the engaged plate 1 is attached to the outer base plate 41'.
8'is erected. An engaging hole 118 'is formed in the substantially center of the engaged plate 18'.

The engaging portion 108b 'is rotated in the vertical direction by the urging force of the spring 20 transmitted through the lever 9, that is, to the position where the abutting portion 108c' abuts the reinforcing plate 107, and in this state The engaging claw 108d 'is the engaging hole 11
It is adapted to be engaged (locked) by being fitted in 8 '. When the lever 9 is pushed upward to release the lock, the locking member 108 rotates counterclockwise so that the engaging claw 108d 'is disengaged from the engaging hole 118'.

As shown in FIG. 11, the mounting plate 19 on the front side has substantially the same structure as the mounting plate 19 ', and the outward base plate 41 is the base plate of the engaged plate 18. Front mounting plate 19, base plates 41, 42 and engaged plate 18
Is formed by cutting a single metal plate into a desired shape and bending it. A U-shaped long groove 1 for attaching the registration roller pair 29 is provided at a proper position in the approximate center of the mounting plate 19.
92 is formed from the upper part toward the lower part. Further, the engaged plate 18 is erected on the outward base plate 41,
An engaging hole 118 into which the engaging claw 108d is fitted is formed at substantially the center of the engaged plate 18. Also, the base plate 4
A rotation shaft 39 of the sheet feeding roller 23, which will be described later, is provided at the tip of the second roller 2.
Restricting pieces 421, 422 for restricting the movement in the axial direction are formed by bending downward.

The mounting structure of the registration roller pair 29 and the mounting structure of the paper feed roller 23 will be described later.

In the above structure, when the upper frame 10 is rotated clockwise about the rotating shaft 14 and the right end portion is lowered by a predetermined amount, the lower portion is recessed in the recess 107a of the position regulating member 107 as shown in FIG. The mounting plate 19 provided on the frame body 11 is fitted therein, and the closing operation of the upper frame body 10 and the displacement in the front-rear direction are restricted. Therefore, the positional displacement of the upper frame 10 with respect to the lower frame 11 in the front-rear direction and the height direction is prevented, and the positional relationship between the members arranged in the upper frame 10 and the members arranged in the lower frame 11 is prevented. Can be held accurately.

Returning to FIG. 21, the document D placed on the document table 2 is conveyed from the right side of the apparatus body 1 to the left side (direction A in the figure), and the document reading provided on the lower portion of the operation panel 3 is performed. The document is read by the unit 17 and discharged onto the document discharge tray 5. The image signal of the document read by the document reading unit 17 is temporarily stored in a memory (not shown) provided inside the apparatus main body 1 and read out according to a facsimile mode or an image forming mode for transmission or transmission. Image forming processing is performed.

That is, in the facsimile mode, the image signals are sequentially read from the memory and transmitted to the designated facsimile machine of the other party through the telephone line. In the image forming mode, the image signal is read out from the memory, the original image is formed on the transfer sheet fed from the sheet feeding cassette 7 by the image forming unit, and then the sheet is discharged to the transfer sheet discharge tray 6.

FIG. 1 is a schematic view showing the internal structure of the facsimile machine, showing the apparatus main body 1 in a closed state. Further, FIG. 2 is a schematic view showing the internal structure of the facsimile machine, and is a view showing a state in which the apparatus main body 1 is opened.

As described above, inside the upper frame 10,
A document reading unit 17, a developing unit 12, and an optical unit 21 of the facsimile section are arranged. The optical unit 21 exposes a document image to the photoconductor drum 121, and the developing unit 12 includes the photoconductor drum 121 and peripheral members such as a developing unit, a cleaning unit, and a charging unit provided around the photoconductor drum 121. It consists of

On the other hand, on the upper surface of the lower frame body 11, a paper feeding portion for feeding the transfer paper from the paper feeding cassette 7, a transfer roller 31 which is pressed against the photosensitive drum 121 and transfers a toner image onto the transfer paper, A fixing device 33 including a guide member 32 for conveying the transfer paper after the transfer to the fixing device 33, a heating roller 331 for fixing the transfer image of the transfer paper, and a pressure roller 332.
Further, a discharge roller pair 35 for discharging the fixed transfer paper to the transfer paper discharge tray 6 is provided. In addition, the transfer paper detection sensor 22 and the transfer paper detection sensor 22 are provided at appropriate positions near the upstream side of the paper feed roller 23, the registration roller pair 29, and the discharge roller pair 35.
28 and 34 are provided.

In addition to the cassette 7, the sheet feeding section mainly includes the sheet feeding roller 23, the guide plate 24, and the C-shaped conveying path 2.
5, a registration roller pair 29 and a guide plate 30. The structure of this paper feeding unit will be described later.

The developing unit 12 includes the upper frame 10.
The original reading unit 17 is disposed on the upper left side of the upper frame 10, and the optical unit 21 is disposed below the original reading unit 17, respectively.

In the document reading unit 17, a document detecting sensor 171 is provided from the upstream side (the document placing table 2 side),
A document feed roller 172, a document pressing plate 173, a separation roller 174, a separating plate 175, a conveyance roller pair 176, a document detection sensor 177, an image reading sensor 178, and a discharge roller pair 179 are provided.

The original detecting sensors 171, 17
7 and the transfer paper detection sensors 22, 28, 34 are known detection sensors including, for example, a photo interrupter and a shield plate.

When a document is set on the document table 2 and the document detection sensor 171 detects that the document is set, the document is fed by the document feed roller 171 and separated by the separating roller 174 and the separating plate 175. Only the document is separated and fed to the pair of transport rollers 176, and the document can be read and transmitted. Subsequently, when transmission is instructed, the pair of transport rollers 176 transports the document to the document reading sensor 178 at a predetermined speed.

The document reading sensor 178 reads the conveyed document in units of a predetermined line width and stores the read image signal in a memory (not shown). Document reading sensor 17
The document being conveyed through the document 8 is detected by the document detection sensor 177, which detects that the document is being read. When the trailing edge of this document passes the document detection sensor 177 and the detection signal of the document detection sensor 177 disappears,
It is determined that the reading of the original is completed, the original is discharged to the original discharge tray 5 by the discharge roller pair 179, and the next original is conveyed to the conveying roller pair 176. Thereafter, the document is sequentially conveyed to the document reading sensor 178 in the same procedure, and the document is read.

The optical unit 21 includes a light emitting portion 211 that emits laser light and a polygon mirror (not shown) that guides the laser light emitted from the light emitting portion 211 to the photosensitive drum 121, and is modulated by a digital image signal. The laser light is reflected through the folding mirror 212 to the photosensitive drum 121.
To form a latent image.

The mounting portion 1 having an opening shape for mounting the above-mentioned paper feeding cassette 7 is formed at the substantially center of the left side surface of the lower frame body 11.
1a is provided, and the paper feed cassette 7 is inserted and mounted in the mounting portion 11a. At the right end of the lower frame body 11, a board arranging portion 11b on which a power board is arranged is provided. Further, inside the lower frame 11, a paper feed roller 23 is arranged at an upper position near the tip of the paper push-up plate 36 of the attached paper feed cassette 7.

FIG. 12 is a sectional view showing the mounting structure of the paper feed roller 23. In this embodiment, two paper feed rollers 23 are fixed at a central portion of the rotary shaft 39 with a predetermined space therebetween, and bearings 40 and 40 'are loosely fitted to both ends of the rotary shaft 39 so that the paper feed roller section is formed. And the bearings 40, 40 'of the paper feed roller portion are provided with a support portion 111 of the lower frame body 11 which will be described later.
The paper feed roller 23 is arranged at a predetermined position of the support frame 11 by being fixedly attached to the a and 113a.

That is, a peripheral groove 39a is provided near the left end of the rotary shaft 39, and a bearing 40 having a flange 40a is rotatably attached to the base end of the peripheral groove 39a. A drive gear (not shown) is attached to the right end of the rotary shaft 39, and a bearing 40 'having the same shape as the bearing 40 is rotatably attached to an appropriate place inside the right end.

A pair of supporting portions 111a and 113a having a semicircular cross section are formed at appropriate positions near the upper end of the rear plate 111 of the lower frame 11 and near the front plate 112 of the upper plate 113. The bearings 40, 40 'are fitted in the bearing portions 111a, 113a and are fixedly supported by the lower frame body 11.

The mounting plate 19 is provided on the upper peripheral surface of the bearing 40.
A restriction piece 421 formed at the tip of the base plate 42 is abutted, and a restriction piece 421 formed at the base of the base plate 42 'of the mounting plate 19' is abutted on the upper peripheral surface of the bearing 40 '. ′ Is abutted, and the upward movement of both bearings 40, 40 ′ is restricted by these restriction pieces 421, 421 ′, and the vertical movement of the rotary shaft 39 is prevented. Also, the base plate 4
The movement of the rotary shaft 39 in the axial direction is restricted by fitting the restriction piece 422 formed at the tip of the second shaft into the circumferential groove 39a of the rotary shaft 39.

As described above, the rotary shaft 39 of the paper feed roller 23
Since the bearings 40, 40 'attached to the lower frame 11 are fitted into the supporting portions 111a, 113a provided in the lower frame 11, the paper feed roller 23 and the rotary shaft 39 can be easily attached to the lower frame 11. Can be installed. Also,
The bearings 40, 40 'are formed by restricting pieces 421, 421' formed on the base plates 42, 42 'of the mounting plates 19, 19'.
Of the rotating shaft 39 is restricted by the restricting pieces 422 formed on the base plate 42, and the bearings 40, 40 'are supported by the supporting portions 111a,
Since the movement of the rotary shaft 39 in the sheet feeding direction is regulated by 113a, it is possible to support the rotary shaft 39 and prevent axial movement thereof with a simple structure.

FIG. 13 is a perspective view showing the appearance of the paper feed cassette 7. The paper feeding cassette 7 is provided with cassette side plates 71, 71 'which are erected on both sides of the cassette bottom plate 710.
Guide part 7 for attaching / detaching to the upper half of the front half of the
2, 72 'are formed. A sheet push-up plate 36 made of metal is provided in the front half of the cassette, and folds 361 and 361 ′ are formed on both sides of the rear end of the sheet push-up plate 36 so as to project outward and serve as rotation shafts. .

The paper push-up plate 36 has the rotating shafts 361, 3
61 'is fitted in holes 711, 711' formed in the cassette side plates 71, 71 'of the paper feed cassette 7 and is rotatably attached. Further, the leading end of the paper push-up plate 36 is biased upward by a spring 37 (see FIG. 1) provided between the cassette 7 and the cassette bottom plate 710, and the leading end of the transfer paper set in the paper cassette 7 is pushed. Is pushed upwards. As a result, when the paper cassette 7 is loaded, the leading end of the uppermost transfer paper is pressed against the lower peripheral surface of the paper feed roller 23. Restriction claws 712 and 712 'are provided on both upper sides of the front end of the cassette.
The regulation claws 712 and 712 'align the leading ends of the stacked transfer sheets, prevent the transfer sheets pushed up by the sheet push-up plate 36 from jumping upward, and further judge the transfer sheets at the time of feeding.

In the paper feeding cassette 7, as shown in FIG. 14, the guide portions 72 and 72 'are attached to the mounting portion 11a of the lower frame body 11.
Guide grooves 114, 11 formed on the inner wall (see FIG. 1)
4'is fitted and slid forward to be mounted. On the inner wall surface of the lower frame body 11, at a position facing the cassette side plate 71, a leaf spring 3 made of metal with one end grounded
8 is projectingly attached to the mounting portion 11a, and the distal end portion 38a of the leaf spring 38 is fitted into the hole 711 of the cassette side plate 71 of the sheet feeding cassette 7 with the sheet feeding cassette 7 mounted at a predetermined position of the mounting portion 11a. Then, the sheet push-up plate 36 is pressed against the rotating shaft 361. This allows
The sheet push-up plate 36 is grounded via a plate spring 38.

As described above, the sheet push-up plate 36 has the leaf spring 38.
Since it is designed to be easily grounded through the paper, the static electricity generated by the paper feed is applied to the paper push-up plate 3
The transfer paper can be preferably supplied without being accumulated in No. 6.

Returning to FIG. 1, a substantially U-shaped guide plate 24 is provided on the downstream side of the paper feed roller 23, and an opening portion is made to face the guide plate 24 so that a substantially C-shaped guide member (hereinafter referred to as a guide member). , C-shaped conveyance path). The C-shaped transport path 25 reverses the transport direction of the transfer paper fed from the paper feed cassette 7 and guides it to the registration roller pair 29 arranged above the paper feed roller 23.

FIG. 15 is a perspective view showing the appearance of the C-shaped conveying path 25. The C-shaped transport path 25 has a semi-cylindrical shape with a C-shaped cross section, and has a width slightly larger than the width dimension of the transfer paper to be transported. C-shaped guide plate 2 for guiding the transfer paper
Reference numeral 51 is curved with a predetermined curvature, and the inner surface of the C-shaped guide plate 251 serves as a guide surface for the transfer paper. A plurality of ribs 252 are formed in parallel on this guide surface. In addition, the bending rate of the C-shaped guide plate 251 is determined by the two end portions 251.
a and 251a 'are larger than the central portion 251b. That is, the upper end of the C-shaped guide plate 251 is horizontal and the lower end is stepped at both ends, and the lower end positions of the both end parts 251a, 251a 'of the C-shaped guide plate 251 are lower than the lower end position of the central part 251b. Both ends 251a and 251a 'of the C-shaped transport path 25 have a curvature ratio of the central portion 2
It is designed to be larger than the bending rate of 51b.

In this way, both end portions 2 of the C-shaped guide plate 251 are
Since the lower end positions of 51a and 251a 'are lower than the lower end position of the central portion 251b, the transfer paper fed from the paper feed cassette 7 by the paper feed roller 23 is
The portion excluding both ends is the C-shaped guide plate 25 of the C-shaped transport path 25.
It comes into contact with the first guide surface and is smoothly conveyed to the C-shaped guide plate 251 as described later.

That is, the transfer paper sent from the paper feed cassette 7 to the C-shaped guide plate 251 of the C-shaped conveying path 25 by the paper feeding roller 23 is the regulating claws 712, 7 of the cassette 7.
12 'makes it easy to make creases on both sides of the leading edge of the transfer paper, and when the leading edge of the transfer paper is conveyed to the C-shaped guide plate 251, both sides of the leading edge (ear portions) are located below the central portion. Although it may hang down, since the lower end positions of both end portions 251a and 251a 'of the C-shaped guide plate 251 are set lower than the lower end position of the central portion 251b as described above, both end edge portions of the transfer paper front end Is C-shaped guide plate 25
The C-shaped guide plate 251 can be reliably transported without colliding with the lower ends of the both end portions 251a and 251a 'of the No. 1 and causing ear breakage.

Since the upper portion of the C-shaped guide plate 251 is linearly formed to the nip point of the registration roller pair 29 to guide the transfer paper linearly, the transfer paper is C-shaped guide plate 251. While being guided by sliding on the guide surface, the transfer paper tips are aligned, and in this state, the transfer paper is suitably conveyed from the upper end of the C-shaped guide plate 251 to the registration roller pair 29.

The shape of the C-shaped guide plate 251 is shown in FIG.
However, the lower end positions of the both end portions 251a and 251a 'may be lower than the lower end position of the central portion 251b. For example, as shown in FIG.
1. The lower end of 1 is smoothly changed so that both ends 251a, 251
The lower end position of a'may be lower than the lower end position of the central portion 251b.

Returning to FIG. 15, a cushioning piece 26 made of an elastic member is attached to the inner side surface of the central portion 251b of the C-shaped guide plate 251 in the vicinity of the lower end thereof with the tip thereof being slightly floating. There is. The buffer piece 26 prevents generation of abnormal noise when the rear end of the transfer sheet is conveyed from the sheet feeding cassette 7 to the C-shaped conveying path 25.

That is, the rear end of the transfer paper is the paper feed cassette 7.
When the sheet is fed from, the front half of the transfer sheet is bent in a C-shape in the C-shaped transport path 25, so that the rear end of the transfer sheet delivered from the sheet feeding cassette 7 is lowered by the restoring force of the transfer sheet. When a force is applied in the direction to transfer from the cassette 7 to the C-shaped guide plate 251, it is struck on the lower end of the C-shaped guide plate 251. The cushioning piece 26 absorbs and alleviates the collision force of the rear end of the transfer paper that is struck on the C-shaped guide plate 251, and prevents the generation of abnormal noise when the rear end of the transfer paper is conveyed to the C-shaped guide plate 251.

Both side surfaces 2 of the C-shaped guide plate 251
Shafts 254 and 254 'are provided at 53 and 253' so as to project outward. The C-shaped transport path 25 has this shaft 25.
4,254 ', the lower frame 11 as shown in FIG.
It is swingably attached to the front and rear side plates (not shown).
The C-shaped conveying path 25 is in a swingable state with the upper frame body 10 opened, so that even when a paper jam occurs in the C-shaped conveying path 25, the C-shaped conveying path 25 is rotated clockwise. The C-shaped transport path 2 is rotated as shown by the phantom line in FIG.
By opening the upper end of 5, jam can be easily removed.

Returning to FIG. 1, the bottom plate portion 2 of the guide plate 24.
4a constitutes an inner guide portion for guiding the feeding direction of the transfer sheet fed from the sheet feeding cassette 7 by the sheet feeding roller 23 in the upper right direction toward the C-shaped conveying path 25, and the upper plate portion 24b. Constitutes an inner guide portion for guiding the transfer paper guided by the C-shaped transport path 25 to the registration roller pair 29.

A pair of rollers 27 are rotatably mounted horizontally at appropriate positions on the upright portion 24c of the guide plate 24. That is, as shown in FIG. 18, the pair of rollers 27 are respectively attached to shafts 271 each of which is a coil-shaped spring stretched between the mounting portions 24d and 24d provided on the lower side of the upright portion 24c of the guide plate 24. It is fitted. The rollers 27 are provided so that the transfer sheet can be smoothly reversed and conveyed by the C-shaped conveying path 25, and by forming the shaft 271 of the rollers by a spring, it is possible to reduce the weight and the cost.

A paper feed guide 44 is provided from the upstream side to the downstream side of each paper feed roller 23. As shown in FIG. 19, the paper feed guide 44 is formed or attached to an appropriate place on the lower surface of the upper plate 113 of the lower frame body 11. This paper feed guide 44 is used for each paper feed roller 2
3 has guide plates 441 and 442 which are erected on both sides thereof, and the upstream sides thereof are formed in a tapered shape, and the downstream sides have a predetermined length. Then, the paper feed guide 44 smoothly guides the transfer paper to the paper feed roller 23, and prevents the transfer paper fed by the paper feed roller 23 from bending and coming into contact with the paper feed roller 23 again to cause a paper jam. To do. The prevention of paper jam in the paper feed guide 44 will be described later.

20A and 20B are views showing the transfer state of the transfer paper in the C-shaped transfer path 25. FIG. 20A is a view showing the transfer state of the front end of the transfer paper, and FIG. FIG. 6C is a diagram showing a conveyance state when the transfer sheet is conveyed, and FIG. 9C is a diagram showing a conveyance state when the transfer sheet is conveyed by the registration roller pair 29.

The transfer paper P sent out from the paper supply cassette 7 to the C-shaped conveying path 25 by the paper supply roller 23 has the leading end of the transfer paper contacting the C-shaped guide plate 251, and the leading end of the transfer paper P is guided to the guide surface. The reverse direction is reversed by sliding to. With the reversing operation of the front end of the transfer paper P, the intermediate portion of the transfer paper P comes into contact with the roller 27 as shown by the alternate long and short dash line in FIG. Being transported while being transported. Then, the tip of the transfer paper P is pressed against the guide surface side by the waist restoring force formed by the rollers 27, and is separated from the guide surface even when being guided by the guide surface at the upper end of the C-shaped guide plate 251. Without doing
It is smoothly and reliably conveyed to the pair of registration rollers 29.

At this time, the registration roller pair 29 has stopped rotating, and the leading edge of the transfer paper P is located at the registration roller pair 29.
By further rotating the paper feed roller 23 in the state of contacting with, the intermediate portion of the transfer paper P is shaped along the C-shaped guide plate 251 as shown in FIG.
As shown by the alternate long and short dash line in FIG. 7B, the bending T occurs at the rear end of the transfer paper P.

When the flexure T increases by a certain amount or more without coming into contact with the paper feed roller 23 by the paper feed guides 441 and 442, the apex of the flexure T comes into contact with the bottom plate portion 24a of the guide plate 24. The skew correction of the transfer sheet is performed by a series of operations.

After that, the registration roller pair 29 is rotationally driven according to the image forming timing, and when the transfer paper P is conveyed, the transfer paper P slides on the rollers 27 and is guided as shown in FIG. Due to the low load of the portion 24a and the rollers 27, the guide surface 24b of the guide plate 24 can be smoothly guided. In this case, the guide portion 24a of the guide plate 24
If the sheet is not provided, the bending T generated on the transfer sheet P becomes large and the leading end of the transfer sheet P abuts the guide surface of the C-shaped guide plate 251 at a large angle to generate a high load. As a result, a jam occurs, or the transfer paper P separates from the guide surface of the C-shaped conveying path 25 and cannot be properly conveyed, which causes a jam, but in the present embodiment, the roller 27 is rotated as described above. Since the rollers 27 are freely installed with a low load, the transfer paper P is smoothly guided by the rollers 27 to the C-shaped conveying path 25 without being bent. As a result, the waist of the transfer paper P bent in the C shape is held, and the transfer paper P is guided while sliding on the guide surface of the C-shaped guide plate 251.

Returning to FIG. 1, a pair of registration rollers 29 is arranged downstream of the guide plate 24. As shown in FIG. 11, the registration roller pair 29 is composed of a driving roller 29a and a driven row 29b, and is formed in a C-shaped long groove 192 formed in the mounting plates 19 and 19 '(the mounting plate 19' is not shown). Bearings 29 provided at both ends of both rollers 29a and 29b
2a and 292b are fitted, and the drive roller 29a is mounted in a pair structure with the back side. The bearing portion 292b of the driven roller 29b is urged by a spring 43 stretched around the mounting plate 19 by sandwiching the long groove 192 with a required pressure in the depth direction of the long groove 192. This urging force prevents the pair of registration rollers 29 from separating from the long groove 192 and presses both rollers, so that the driving roller 2
The relative positional relationship between 9a and the driven roller 29b is stabilized, and the mounting structure of the registration roller pair 29 is simplified.

With the above configuration, when the received signal or the image of the original image is formed, the transfer paper is fed from the paper feed cassette 7 by the paper feed roller 23, and passes through the guide plate 24 and the C-shaped conveying path 25. The sheet is reversed and fed to the registration roller pair 29 arranged above the sheet feeding roller 23. Further, the transfer sheet is fed to the photosensitive drum 121 by the registration roller pair 29 in synchronization with the exposure timing of the optical unit 21, and the toner image on the surface of the photosensitive drum is transferred from the transfer roller 31 to the transfer sheet. Then, after the transfer paper is fixed by the fixing device 33, it is discharged onto the discharge tray 6 by the discharge roller pair 35.

[0089]

According to the present invention, the inversion guide portion having a C-shaped cross section is formed such that both end portions of the upstream end thereof have a step outward in the vertical direction with respect to the central portion, and at the downstream end. Since the structure eliminates the step, both side edges of the sheet to be fed are suitably slidably contacted with the inner wall of the reversing guide portion, so that the direction of the sheet can be smoothly and easily reversed (Claim 1).

Further, according to the present invention, since the rotatable shaft supporting structure is provided on both side surfaces of the inversion guide portion having the C-shaped cross section,
Jam removal and cleaning can be performed easily (claim 2).

Further, according to the present invention, a roller which is in the opening surface of the reversing guide portion having a C-shaped cross section, which is close to the upstream end side of the reversing guide portion and which is axially supported in the lateral direction is provided. Since the sheet is provided, the direction of the sheet can be reliably and smoothly reversed (claim 3).

Further, according to the present invention, since the elastic member is provided on the inner wall near the upstream end of the reversing guide portion having the C-shaped cross section in the state that the front end thereof is floated, the rear end of the paper is It is possible to prevent generation of abnormal noise due to impact when the sheet moves from the cassette to the reversing guide portion (claim 4).

Further, according to the present invention, the height is between the vicinity of the paper feed roller in the direction orthogonal to the paper feed direction and the downstream guide on the downstream side in the paper feed direction, and the height of the paper feed roller is the same as that of the paper feed roller. Since the guide member lower than the paper contact position of the paper roller is arranged in the apparatus main body, it is possible to smoothly guide and feed the fed paper to the downstream guide without jamming. .

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an internal structure of a facsimile machine as an application example of the present invention, and is a diagram showing a state in which an apparatus body is closed.

FIG. 2 is a schematic view showing an internal structure of the facsimile, showing an opened state of an apparatus main body.

FIG. 3 is a perspective view of an essential part showing a state in which an upper frame body and a lower frame body of the apparatus body are opened.

FIG. 4 is a perspective view of a main part in which a developing unit is added in FIG.

FIG. 5 is a perspective view of an essential part showing the shape of the front side plate.

6A and 6B are views showing a mounting structure between a front side plate, a rear side plate, and a reinforcing plate, FIG. 6A is a plan view, and FIG. 6B is a right side view.

FIG. 7 is a perspective view illustrating attachment of a document reading unit to a front side plate and a rear side plate.

8A and 8B show structures of a position regulating member and a lock member, FIG. 8A is a partial right side view of an upper frame body, and FIG. 8B is a partially enlarged view showing a shape of a concave portion of the position regulating member.

FIG. 9 is a right side view of a part of the lower frame showing the lock mechanism of the upper frame and the lower frame.

FIG. 10 is a front sectional view of an essential part of an upper frame, showing a structure of a position regulating member and a lock member.

FIG. 11 is a partial perspective view showing the structure of a mounting plate on the front side.

FIG. 12 is a partial cross-sectional view showing a mounting structure of a paper feed roller.

FIG. 13 is a perspective view showing the outer appearance of a paper feed cassette.

FIG. 14 is a schematic plan view illustrating how the paper feed cassette is attached to the apparatus main body.

FIG. 15 is a perspective view showing the appearance of a C-shaped transport path.

FIG. 16 is a plan view showing another embodiment of the shape of the C-shaped guide plate.

FIG. 17 is a side view for explaining the rotation of the C-shaped guide plate.

FIG. 18 is a perspective view showing a roller attached to an upright portion of a guide plate.

FIG. 19 is a partial perspective view showing the structure of the paper feed guide.

FIG. 20 is a side view showing a conveyance state of a sheet on a C-shaped conveyance path, FIG. 20A is a diagram showing a conveyance state of a front end of a transfer sheet,
FIG. 7B is a diagram showing a conveyance state when the leading edge of the transfer sheet is nipped by the registration roller pair, and FIG. 9C is a diagram showing a conveyance state when the transfer sheet is conveyed by the registration roller pair.

FIG. 21 is a perspective view showing the outer appearance of a facsimile equipped with an image forming apparatus to which the present invention is applied.

[Explanation of symbols]

 1 Device Main Body 7 Paper Feed Cassette 71,71 'Side Plate 711,711' Hole 712,712 'Control Piece 9 Lever 10 Upper Frame 10a Storage Section 101 Front Side Plate 101a, 102a Side Plate Section 101b, 102b Peripheral Section 102 Rear Side Plate 11 Lower Section Frame 11a Mounting portion 103-106 Reinforcing plate 107 Position regulating member 107a Recess 107b Tapered portion 107c Small width portion 107d Cutout portion 108 Lock member 108d, 108d 'Engaging claw 12 Developing unit 118, 118' Engaging hole 19, 19 ' Mounting plate 192 Long groove 20 Spring 23 Paper feed roller 24 Guide plate 24a Bottom plate part 24b Upper plate part 24c Upright part 24d Mounting part 25 C-shaped transport path 251 C-shaped guide plate 251a, 251a 'Both ends 251b Central part 252 Rib 253, 253 ′ Side 254, 254 ′ axis 26 cushioning piece 27 roller 271 shaft 29 registration roller pair 29a driving roller 29b driven roller 292a, 292b bearing portion 36 paper pushing plate 361, 361 'rotating shaft 38 leaf spring 39 rotating shaft 38a tip portion 39a circumferential groove 40, 40' bearing 421, 421 ', 422 Control piece 43 Spring 44 Paper feed guide 441, 442 Guide plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takeshi Uemura 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Industrial Co., Ltd. (72) Masahiko Miyazaki 1-228 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (72) Inventor Hiroyuki Ueda 1-228 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Co., Ltd. (72) Shinichi Kodera 1-2-2 Tamatsukuri, Chuo-ku, Osaka Mita Kogyo Within the corporation

Claims (5)

[Claims] 1. A paper feeding unit for reversing the direction of a sheet fed from an upstream side to feed the sheet to a downstream side, wherein the sheet feeding section has a cross section having a lateral dimension substantially the same as the width of the fed sheet. It is composed of a C-shaped reversing guide part, and the reversing guide part is formed such that both end parts of its upstream end have a step outward in the vertical direction with respect to the central part, and there is no step difference at the downstream end. The structure of the paper feed section, which is characterized by 2. A paper feeding unit for reversing the direction of a paper fed from an upstream side and feeding the same to a downstream side, wherein the paper feeding unit is composed of a reversing guide section having a C-shaped cross section, and both side surfaces of the reversing guide section. A paper feed unit structure having a rotatable shaft support structure. 3. A sheet feeding unit for reversing the direction of a sheet fed from the upstream side and feeding the sheet to the downstream side, wherein the sheet feeding section has a cross section having a lateral dimension substantially the same as the width of the fed sheet. It is composed of a C-shaped reversing guide part and a roller which is in the opening surface of the reversing guide part and which is adjacent to the upstream end side of the reversing guide part and axially supported in the lateral direction. A paper feeding unit structure characterized by assisting smooth reversal of paper. 4. A sheet feeding unit for reversing the direction of a sheet fed from an upstream cassette and feeding the sheet to a downstream side, wherein the sheet feeding unit has a C-shaped cross section and a reversing guide plate. A sheet feeding unit structure, characterized in that an elastic member is provided on an inner wall near the upstream end with the tip thereof being floated toward the upstream side. 5. A paper feed unit having a paper feed roller, which is located on the upper surface of the cassette when the cassette is attached to the apparatus main body, and feeds the paper stacked in the cassette to a downstream guide. A guide member is provided between a position near the paper feed roller in a direction orthogonal to the paper feed direction and the downstream guide on the downstream side in the paper feed direction, and the height thereof is lower than the paper contact position of the paper feed roller. A sheet feeding unit structure, which is disposed in the apparatus body.