JP2002265074A - Paper feeding mechanism of image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper feeding mechanism of an image forming apparatus capable of reducing noise of the device by driving a movable member (contact and separating plate) of a manual feed cassette for pressing a paper sheet to a paper feed roller and releasing the same without a solenoid, and preventing the paper sheet from being pressed to the paper feed roller. SOLUTION: This paper feeding mechanism is provided with a contact and separating plate driving means 11 operated interlocking with the rotation of the paper feed roller 3. When the paper feed roller 3 is rotated (rotated in the normal direction) in the paper feeding direction, the contact and separating plate 2a is caused to press the paper sheet to the paper feed roller 3 by a contact and separating plate driving means 11, and when the paper feed roller 3 is rotated (rotated in the reverse direction) to the paper feed direction, the contact and separating plate 2a is caused to release pressing between the paper and the paper feed roller 3 by the contact and separating plate driving means 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper feeding mechanism for an image forming apparatus such as a copying machine, a printer, and a facsimile, and more particularly, to a paper feeding mechanism for an image forming apparatus for feeding paper from a manual feed cassette. About.

[0002]

2. Description of the Related Art In general, a paper feeding mechanism of an image forming apparatus stores one or a plurality of paper feeding cassettes in which paper of a specific size is stored in advance and / or manually feeds a paper of an unspecified size when used by a user. A manual cassette is provided. However, in recent years, the number of paper feed cassettes has been reduced or eliminated by improving the paper storage capacity of the manual feed cassette to increase the number of sheets stored in the manual feed cassette in order to reduce the size of the apparatus. is there.

In such a manual feed cassette, it is necessary to press the paper against a paper feed roller at the time of feeding the paper in order to feed the stored paper to the paper transport path. It is necessary that the pressing be released. This is because if the paper is manually fed while the paper is being pressed by the paper feed roller, the leading end of the paper may be broken. For this reason, conventionally, a manual member is provided with a movable member (separation plate or the like) for pressing and releasing the paper against the paper feed roller, and the movable member is operated by a solenoid or the like. A structure for pressing and releasing the paper against the paper roller is adopted.

[0004] As this kind of prior art, there is, for example, JP-A-6-298381.

[0005]

However, in the above-mentioned prior art, in order to store a larger number of sheets in the manual feed cassette, the distance between the sheet feeding roller and the movable member becomes longer, and the operation stroke of the solenoid is increased. However, a large solenoid is required. Therefore, the operation sound (ON-OFF) of the solenoid increases the operation sound generated from the solenoid and the impact sound generated from the sheet feeding roller, and as a result, there is a problem that the apparatus noise increases. It is desired that the device noise is 58 dB or less.)

When the paper is pressed against the paper feed roller for a long time, the paper is curled (deformed) at the contact portion between the paper and the paper feed roller. There is a possibility that a paper jam occurs in the paper feeding mechanism.

Further, when the paper is pressed against the paper feed roller for a long time, paper in contact with the paper feed roller, particularly OHP paper, paper dedicated to ink jet (paper whose paper surface is surface-treated), etc. Therefore, when the rubber component of the paper feed roller rubber is transferred to the surface and image data is printed on the transferred portion, the print quality may be deteriorated in this portion.

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation, and reduces the device noise by driving a movable member of a manual feed cassette for pressing and releasing a sheet against a sheet feed roller without using a solenoid. An object of the present invention is to provide a sheet feeding mechanism of an image forming apparatus in which the number of sheets is reduced and a sheet is not pressed against a sheet feeding roller for a long time.

[0009]

In order to solve the above-mentioned problems, the paper feeding mechanism of the image forming apparatus according to the present invention employs the following means.

A first gist of the present invention is to provide a manual feed cassette for storing paper, and a paper feed roller unit for separating sheets one by one from the manual feed cassette and feeding the separated paper to a paper transport path. In a paper feeding mechanism of an image forming apparatus provided with a separation / contact plate capable of pressing a sheet to a paper feeding roller and releasing the same, a separation / plate driving means which operates in conjunction with rotation of the sheet feeding roller is provided. When the paper roller rotates in the paper feed direction (forward rotation), the release / contact plate driving means presses the paper against the paper feed roller, and the paper feed roller rotates in the direction opposite to the paper feed direction (reverse rotation). The present invention relates to a sheet feeding mechanism of an image forming apparatus, wherein when the sheet is rotated, the pressing and separating plate releases the pressing of the sheet and the sheet feeding roller by the separating and driving plate driving means.

According to the first aspect of the present invention, when the paper feed roller rotates forward, the separation / contact plate of the manual feed cassette is driven by the separation / contact plate driving means in the direction in which the paper is pressed against the paper feed roller, and the paper is fed. The roller is pressed. When the paper feed roller rotates in the reverse direction, the separation / contact plate of the manual feed cassette is driven by the separation / contact plate driving means in a direction to separate the paper and the paper feed roller, and the pressing between the paper and the paper feed roller is released.

According to a second aspect of the present invention, the separation / contact plate driving means includes a paper feed roller gear connected to the paper feed roller, a first planetary gear meshing with the paper feed roller gear, and the paper feed roller rotating forward. A first planetary gear driving gear meshing with the first planetary gear, a second planetary gear meshing with the paper feed roller gear, and a second planetary gear driving gear meshing with the second planetary gear by rotating the paper feeding roller in reverse. And a cam that rotates in conjunction with the first separation / contact plate driving gear and the second separation / contact plate driving gear and is engaged with the separation / contact plate so as to drive the separation / contact plate. A first aspect of the present invention relates to a sheet feeding mechanism of an image forming apparatus, wherein a contact plate is driven.

According to a second aspect of the present invention, when the paper feed roller rotates forward, the paper feed roller gear connected to the paper feed roller also rotates forward, and the first planetary gear of the paper feed roller gear is used as the paper feed roller gear. The gear moves in the forward rotation direction while meshing with the first separating / contacting plate driving gear to rotate the first separating / contacting plate driving gear. The paper feed roller is driven in the direction of pressing. When the paper feed roller rotates in the reverse direction, the paper feed roller gear connected to the paper feed roller also rotates in the reverse direction, and the second planetary gear of the paper feed roller gear moves in the reverse rotation direction while meshing with the paper feed roller gear, thereby causing the second rotation. The second separation / contact plate driving gear is rotated by meshing with the separation / contact plate driving gear, and the separation / contact plate is driven by a cam connected to the second separation / contact plate driving gear in a direction to release the pressing between the sheet and the paper feed roller. Is done.

A third gist of the present invention resides in that the cam, the first separation / contact plate drive gear, and the second separation / contact plate drive gear are coaxially arranged. The present invention relates to a paper feed mechanism of an image forming apparatus.

According to the third aspect of the present invention, since the cam, the first separating / contacting plate driving gear, and the second separating / contacting plate driving gear are coaxially arranged, the shape of the cam is simplified. At the same time, the positional accuracy of the cam and the first and second contact plate driving gears is improved.

A fourth gist of the present invention is that the first and second separation / plate driving gears are composed of a first planetary gear, a first separation / plate driving gear, a second planetary gear and a second planetary gear. The present invention relates to a sheet feeding mechanism for an image forming apparatus according to any one of the first to third aspects, characterized in that the gear is a toothless gear whose engagement with the separation / contact plate driving gear is within a predetermined angle range.

According to a fourth aspect of the present invention, the first planetary gear and the first separation / contact plate driving gear mesh with each other within a predetermined angle range,
The cam is rotated by a predetermined angle to press the paper against the paper feed roller, and thereafter, it is in a free state without being engaged with each other. Further, the second planetary gear and the second separation / contact plate driving gear mesh with each other within a predetermined angle range, rotate the cam by a predetermined angle to release the pressing between the paper and the paper feed roller, and thereafter are in a free state without mutual mesh. Becomes

According to a fifth aspect of the present invention, there is provided an image forming apparatus according to any one of the first to fourth aspects, wherein a portion of the cam which engages with the separation plate is formed with a smooth curved surface. Paper feed mechanism.

According to the fifth aspect of the present invention, since the cam is formed with a smooth curved surface at the portion engaging with the separation / contact plate, the rotation of the cam causes the paper to be gradually pressed by the paper feed roller. At the same time, the pressing between the paper and the paper feed roller is gradually released.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a paper feed mechanism of an image forming apparatus according to the present invention will be described below with reference to the drawings.

FIGS. 1 to 8 illustrate an embodiment (1) of a sheet feeding mechanism of an image forming apparatus according to the present invention.

FIG. 1 is a side sectional view showing an image forming apparatus 1 (small ink jet printer) using an ink jet type recording head on which a paper feeding mechanism of the image forming apparatus according to the present invention is mounted. First, a schematic configuration of the image forming apparatus 1 and a printing process will be described with reference to FIG.

The image forming apparatus 1 includes a manual feed cassette 2, a feed roller unit (a feed roller 3 and a separating unit 4), a paper detection sensor 5, a pair of PS rollers 6, a printing unit 7, a platen 8, and a discharge roller 9. It is schematically configured.

The manual feed cassette 2 is for storing paper and is disposed at the right end of the side surface of the image forming apparatus 1 and is inclined from the lower side of the apparatus toward the upper right direction. The manual feed cassette 2 is provided with a separation / contact plate 2a. The separation / contact plate 2a is rotatably locked at the upper end 2c of the manual feed cassette main body, and has a lower end between the manual feed cassette main body. It is urged toward the paper feed roller 3 by a provided spring 2d. The paper sheet is placed on the manual feed cassette 2 with its leading end inserted into the space W between the separation plate 2a and the paper feed roller 3, and a printing command based on image data from a computer or the like (not shown) is issued. When the image forming apparatus 1 receives the image, the separation / contact plate 2a is driven and is pressed against the paper feed roller 3 by the urging force of the spring 2d. The driving means of the separation / contact plate 2a will be described later.

The paper feed roller section (the paper feed roller 3 and the separating section 4) separates the sheets placed on the manual feed cassette 2 one by one and feeds them to the sheet transport path 5a. The paper feed roller 3 is rotated by a driving force from a driving source (not shown) such as a motor (the direction of arrow R is forward rotation).
The separating section 4 includes a separating pad 4a and a spring 4b, and the separating pad 4a is pressed against the paper feed roller 3 by the urging force of the spring 4b.

The paper detection sensor 5 detects the leading end of the paper fed to the paper transport path 5a by the paper feed roller 3 and the separation unit 4, and detects the paper at the downstream side of the paper feed roller 3. It is arranged on the transport path 5a.

The pair of PS rollers 6 is disposed downstream of the paper transport path 5a, and transports the paper detected by the paper detection sensor 5 to the printing unit 7 and prints the paper based on image data. This is for adjusting the position where the image data is printed on the paper by controlling the timing of transporting the image data to the printing unit 7. The PS roller pair 6 is rotated by a driving force from a driving source (not shown) such as a motor.

The printing unit 7 prints on paper conveyed onto a platen 8 by discharging ink from a required ink head (not shown) in accordance with image data. An ink carriage (not shown) and an ink carriage holding shaft (not shown) arranged to facilitate the scanning.

When printing the image data on the paper, the rotation of the pair of PS rollers 6 is controlled so that the paper is temporarily stopped at a low speed, and the scanning of the ink carriage for one line (one direction) is completed. At this point, paper corresponding to a plurality of ink nozzles of the ink head is conveyed. The image data is reproduced on the paper by continuing this processing, and thereafter the paper passes through an ink drying unit (not shown) and a driving source (motor, not shown)
The sheet is conveyed to a sheet discharge roller 9 rotated by a driving force from the image forming apparatus and is discharged outside the image forming apparatus 1.

FIG. 2 is a perspective view showing the sheet feeding mechanism 10 of the image forming apparatus 1 according to the present invention. The paper feed mechanism 10 of the image forming apparatus 1 is roughly composed of a separation / contact plate 2 a of the manual feed cassette 2, a paper feed roller 3, a separating unit 4, a paper detection sensor 5, and a separation / plate drive unit 11.

As shown in FIGS. 3 and 4, the separation / contact plate 2a is
The separation / contact plate 2a is formed in a substantially rectangular plate shape. The separation / contact plate 2a has a width direction A of a sheet placed on the separation / contact plate 2a.
The paper guide 2e is slidably engaged with the separation / contact plate 2a, the projections 2h and 2i provided at the upper end of both side surfaces 2f and 2g of the separation / contact plate, and the lower end of the side end surface. Projection 2 engaging with cam 26 of separation / contact plate driving means 11
b. The separation / contact plate 2a has protrusions 2f, 2g provided on the separation / contact plate 2a, and holes 2m provided on both side plates 2j, 2k of the manual feed cassette 2, respectively.
2n so as to be rotatable.

The paper feed roller 3 is formed in a cylindrical shape, and at least the outer peripheral portion is formed of a rubber member. A coaxial shaft 3a penetrates the center of the paper feed roller 3, and the paper feed roller 3 is fixed to the shaft 3a. Both ends 3b and 3c of the shaft 3a are rotatably supported by both side plates 2j and 2k of the manual cassette. The shaft 3a is connected to one end (for example, the end 3).
c side) penetrates the side plate 2j and extends to the outside, and this extended portion is connected to the separation / contact plate driving means 11.

FIGS. 5 and 6 are side views showing the detailed mechanism of the separation / contact plate driving means 11. FIG. The separation / contact plate driving means 11 includes a paper feed roller gear 21, a first planetary gear 22, and a second planetary gear 2.
3. First separation / contact plate drive gear 24, second separation / contact plate drive gear 2
5, the cam 26 and the side plate 11a.

The feed roller gear 21 is coaxially fixed to one end of the shaft 3a to which the feed roller 3 is fixed and extends from a side plate (for example, the side plate 2j).

The first planetary gear 22 includes a feed roller gear 21
The first planetary gear 22 moves in the rotation direction (arrow B1 direction) while rotating by the rotation of the paper feed roller gear 21 (arrow X1 direction), and the first planetary gear 22 is connected to the first separation / contact plate gear. State (at this time,
The shaft 22a of the first planetary gear is configured to rotate at that position at one of the arc portions of the oblong hole 11b of the side plate 11a). More specifically, for example, the feed roller gear 21 and the first planetary gear
1a and the shaft 22a are connected by a friction belt 212. The first planetary gear 22 moves in a direction (arrow B2 direction) away from the first separation / contact plate driving gear when the paper feed roller gear 21 rotates in the arrow X2 direction (by this movement, the first planetary gear becomes: The shaft 22a of the first planetary gear is
(1a) and stops at the other arc portion of the oval hole 11b).

The second planetary gear 23 includes a paper feed roller gear 21
The paper feed roller gear 21 rotates in the rotation direction (arrow C2 direction) in accordance with the rotation (arrow X2 direction) of the paper feed roller gear 21 while the second planetary gear 23 is in contact with the second separation plate gear. 25 (at this time, the shaft 23a of the second planetary gear is connected to the oblong hole 11 of the side plate 11a).
c), it is configured to rotate at that position. More specifically, for example, the feed roller gear 21 and the second planetary gear 23 have their respective shafts 21a and 23a connected by a friction belt (not shown). Note that the second planetary gear 23 moves in a direction (arrow C1 direction) away from the second separation / contact plate driving gear 25 when the paper feed roller gear 21 rotates in the direction of arrow X1 (this movement causes the second planetary gear to rotate). Then, the shaft 23a of the second planetary gear abuts against the other arc portion of the oblong hole 11c of the side plate 11a and stops.

The first separating / contacting plate driving gear 24 can mesh with the first planetary gear 22, and is rotatably supported by a side plate (for example, the side plate 2j and / or 11a) by a shaft 24a. . The first separation / contact plate driving gear 24 is a toothless gear having a toothless portion 24a. The position and angle θ of the missing tooth are determined by the cam 26 connected to the first separation / contact plate drive gear 24, the separation / contact plate 2a being driven a predetermined distance, and the first separation / contact plate 2a being driven by the predetermined distance. The rotational force of the planetary gear 22 is set so as not to be transmitted to the first separation / contact plate driving gear 24. For example, FIG.
As shown in (a), in the initial state before rotating the cam 26 (the state at the time of the home position described later), the position of the missing tooth and the angle θ are set to the center of the first separation / contact plate driving gear 24 and the first The angle θ of the missing tooth becomes 80 degrees from a position of 100 degrees in a direction opposite to the rotation direction (the direction of the arrow Z1) of the first separation / contact plate driving gear 24 with respect to a straight line connecting the center of the planetary gear 22. I have.

The second separation / contact plate drive gear 25 is meshable with the second planetary gear 23, and is rotatably supported by a side plate (eg, the side plate 2j and / or 11a) by a shaft 25a. . The second separation / contact plate driving gear 25 is a toothless gear having a toothless portion 25a. The position and angle θ of the missing tooth are determined by the cam 26 connected to the second separation / contact plate driving gear 25, the separation / contact plate 2a is driven by a predetermined distance, and after the separation / contact plate 2a is driven by the predetermined distance, The rotation force of the planetary gear 23 is set so as not to be transmitted to the second separation / plate driving gear 25. For example, FIG.
As shown in (a), the position and angle θ of the missing tooth in the initial state before the rotation of the cam 26 (the state when a sheet described later is pressed by the paper feed roller 3) are determined by the second separation / contact plate. The rotation direction of the second planetary gear 23 (arrow Z2) with respect to a straight line connecting the center of the drive gear 25 and the center of the second planetary gear 23
Direction) from the position of 100 degrees in the opposite direction
Is 80 degrees.

The first and second contact plate driving gears 24 and 25 can be arranged coaxially, and this shaft is rotatably supported by the side plate 2j and / or 11a. .

The cam 26 is formed in a substantially disc shape, is disposed inside or outside each of the gears, and is engaged with the projection 2b of the separation / contact plate 2a. Cam 26
Is driven by a first separation and contact plate drive gear 24 and a second separation and contact plate drive gear 25. The cam 26 has, for example, a first separation / contact plate driving gear 24 and a second separation / contact plate driving gear 25 arranged coaxially, and is fixed to the axis with its axis as the center of rotation. Further, the engagement between the cam 26 and the separation / contact plate 2a is
For example, the structure is such that the protrusion 2b of the separation / contact plate 2a contacts the contour of the cam 26. In this case, the contour of the cam 26 is preferably formed with a smooth curved surface. Note that the contour (pitch curve) of the cam 26 is the protrusion 2b of the separation / contact plate 2a.
It is formed such that the displacement of (pitch point) is a predetermined distance.

The side plate 11a is for regulating the moving range of the first planetary gear 22 and the second planetary gear 23,
For example, it is supported by the side plate 2j by the shaft 21a and the shaft 24b (or the shaft 25b). The moving range of the first planetary gear 22 is regulated by the oblong hole 11b, and the moving range of the second planetary gear is regulated by the oblong hole 11c. The movement range H is substantially equal to the first planetary gear 22 and the first separation / contact plate driving gear 24 and the second planetary gear 23 and the second separation / contact plate driving gear 2
5 are set to the distances at which they mesh with and separate from each other.

Next, the operation of the paper feed mechanism 10 of the image forming apparatus 1 configured as described above will be described. In the initial state, the separation / contact plate 2a and the paper feed roller 3 are separated from each other at an interval W sufficient to store the paper. Hereinafter, the initial position of the separation / contact plate 2a is referred to as a home position.

First, the paper feed roller 3 is rotated forward by the driving force of a drive source (not shown) (not shown), and the paper feed roller gear 21 connected to the paper feed roller 3 also rotates in the same direction (the direction of arrow X1). Then, in conjunction with the rotation of the paper feed roller gear 21, the first planetary gear 22 meshing with the paper feed roller gear 21 rotates and moves in the forward rotation direction (the direction of arrow B1).

Then, the first planetary gear 22 meshes with the first separating / contacting plate driving gear 24, and the first planetary gear 22 stops at that position and rotates to rotate the first separating / contacting plate driving gear 24 in the direction of arrow Y1. (At this time, the shaft 22a of the first planetary gear is
1a is in contact with one arc portion of the oblong hole 11b).

Then, the first separation / contact plate driving gear 24 rotates the connected cam 26 in the direction of arrow D1. At this time, the separation / contact plate 2a is moved by the spring 2d to the sheet feeding roller 3a.
The projection 2b of the separating / contacting plate 2a is pressed against the contour of the cam 26 because it is urged in the direction. For this reason, the rotation of the cam 26 causes the separation / contact plate 2 a to be displaced from the home position in the direction of the paper feed roller 3 (the direction of the arrow E <b> 1) along the contour (pitch curve) of the cam 26. 2a
When the sheet stored between the rollers is pressed by the sheet feed roller 3, the sheet stops at that position. When no paper is stored, the cam 26 rotates and stops at least to a position where the separation / contact plate 2a can contact the paper feed roller 3.

Here, the first separating / contacting plate driving gear 24 is a toothless gear. When the first separating / contacting plate driving gear 24 rotates to the toothless portion 24a, the transmission of the rotational force from the first planetary gear 22 is performed. As a result, the rotation of the cam 26 is stopped. In addition,
In this case, the positional relationship between the first planetary gear 22 and the toothless portion 24a of the first separation / contact plate driving gear 24 is, for example, as shown in FIG.
When the first separation / contact plate drive gear 24 rotates, for example, 100 degrees from the state at the home position of (a) to the state at the time when the sheet of (b) is pressed by the paper feed roller 3, the toothless portion 24a Reach

Further, since the first separation / contact plate driving gear 24 and the second separation / contact plate driving gear 25 are formed coaxially, the first separation / contact plate driving gear 24 is pressed against the paper feed roller 3 by the paper. 7B, the second separation / contact plate drive gear 25 is also in the state where the paper is pressed by the paper feed roller 3 (FIG. 8A).

Next, when the feeding operation of the sheets stored in the manual feed cassette 2 is completed, the paper feed roller 3 is rotated reversely by the driving force of a drive source (motor or the like, not shown), and is connected to the paper feed roller 3. The feed roller gear 21 also rotates in the same direction (the direction of the arrow X2), and the first planetary gear 22 meshing with the feed roller gear 21 rotates in the reverse direction in conjunction with the rotation of the feed roller gear 21. (In the direction of arrow B2) (at this time, the first planetary gear is connected to the shaft 22a of the first planetary gear by the oblong hole 11 of the side plate 11a).
b) and stops at the other arc.

The second planetary gear 2 meshed with the feed roller gear 21 in conjunction with the rotation of the feed roller gear 21.
Reference numeral 3 rotates and moves in the reverse rotation direction (the direction of arrow C2). Then, the second planetary gear 23 meshes with the second separation / contact plate driving gear 25, and the second planetary gear 23 stops at that position and rotates by itself to rotate the second separation / contact plate driving gear 25 in the arrow Y2 direction (at this time, The shaft 23a of the second planetary gear is connected to the side plate 11a.
Of the elliptical hole 11c).
Note that the second planetary gear 23 is separated from the second separation / contact plate drive gear 25 and stopped when the first planetary gear 22 is engaged with the first separation / contact plate drive gear 24 (at this time, The shaft 23a of the second planetary gear is connected to the oblong hole 11 of the side plate 11a.
c).

Then, the second separation / contact plate driving gear 25 rotates the connected cam 26 in the direction of arrow D2. Cam 2
6 starts rotating in the direction of the arrow D2, the contour of the cam 26 comes into contact with the projection 2b of the separation / contact plate 2a, and the separation / contact plate 2a is separated from the paper feed roller 3 against the urging force of the spring 2d (arrow). (E2 direction). Then, the separation / contact plate 2a is returned to the home position.

Here, the second separating / contacting plate driving gear 25 is a toothless gear. When the second separating / contacting plate driving gear 25 rotates to the toothless portion 25a, the transmission of the rotational force from the second planetary gear 23 is performed. As a result, the rotation of the cam 26 is stopped. In addition,
In this case, the positional relationship between the second planetary gear 23 and the toothless portion 25a of the second separation / contact plate driving gear 25 is, for example, as shown in FIG.
When the state shown in (a) is pressed by the paper feed roller 3 to the state shown in (b) at the home position, when the second separation / contact plate driving gear 25 rotates, for example, 100 degrees, the missing tooth portion 24a Reach

Further, since the first gear 24 and the second gear 25 are formed coaxially, the second gear 25 is in the home position (FIG. 8).
When (b)) is reached, the first separation / contact plate drive gear 24 is also in the state at the time of the home position (FIG. 7A).

As described above, according to this embodiment, when the feed roller 3 rotates forward, the feed roller gear 21 connected to the feed roller 3 also rotates forward, and the first planetary gear 22 of the feed roller gear 21 rotates. The cam which is moved in the forward rotation direction while meshing with the paper feed roller gear 21 and meshes with the first separation / contact plate drive gear 24 to rotate the first separation / contact plate drive gear 24, and is connected to the first separation / contact plate drive gear 24 26 separates and separates plate 2
a is driven in a direction to press the paper and the paper feed roller 3. When the feed roller 3 rotates in the reverse direction, the feed roller gear 21 connected to the feed roller 3 also rotates in the reverse direction, and the second planetary gear 23 of the feed roller gear 21 meshes with the feed roller gear 21 in the reverse rotation direction. , And meshes with the second separation / contact plate driving gear 25 to rotate the second separation / contact plate driving gear 25, and the cam 2 connected to the second separation / contact plate driving gear 25
6, the separation / contact plate 2a is driven in a direction to release the pressing between the sheet and the paper feed roller 3. Thus, it is possible to press and release the sheet and the paper feed roller 3 by the separation / contact plate 2a of the manual feed cassette 2 using the rotational force of the forward and reverse rotation of the paper feed roller 3 without using the solenoid. Therefore, noise of the image forming apparatus can be reduced.

Further, since the paper is pressed against the paper feed roller 3 simultaneously with the paper feeding operation, the paper is not pressed against the paper feed roller 3 for a long time, and curl (deformation) occurs at the leading end of the paper. Thus, it is possible to perform good paper feeding without causing paper jams.

Further, since the paper is pressed against the paper feed roller 3 simultaneously with the paper feeding operation, the paper is not pressed against the paper feed roller 3 for a long time, and the rubber component of the paper feed roller 3 is applied to the paper. Transfer can be suppressed, and print quality at the leading edge of the paper does not deteriorate.

Further, since the cam 26, the first separation / contact plate driving gear 24, and the second separation / contact plate driving gear 25 are coaxially arranged, the shape of the cam 26 is simplified, and
The positional accuracy between the cam 26 and the first and second contact plate driving gears 24 and 25 is improved.

Further, the first separation / contact plate driving gear 24 and the second separation / contact plate driving gear 25 are connected to the first planetary gear 22, the first separation / contact plate driving gear 24 and the second planetary gear 23, and the second separation / contact. The first planetary gear 22 and the first separating / connecting plate drive gear 24 mesh with the plate drive gear 25 within a predetermined angle range, and rotate the cam 26 by a predetermined angle. The paper is pressed against the paper feed roller 3 and thereafter enters a free state without meshing with each other. Also, the second planetary gear 23
And the second separation / plate driving gear 25 are engaged with each other in a predetermined angle range, and the cam 26 is rotated by a predetermined angle to release the pressing between the sheet supply roller 3 and the sheet. Thus, the separation / contact plate 2a is moved to a predetermined position (at least at a position where the paper is pressed by the paper feed roller 3 when the paper feed roller 3 rotates forward, and at a position where the paper feed roller 3 is rotated reversely). At the home position).

Next, an embodiment (2) of the sheet feeding mechanism of the image forming apparatus according to the present invention will be described. FIG. 9 shows an embodiment (2) of the sheet feeding mechanism of the image forming apparatus according to the present invention. In the description similar to that of the embodiment (1), the same reference numerals are given and the details are omitted.

The paper feed mechanism 10a of the image forming apparatus according to the embodiment (2) has an outline of the cam 26 which is a smooth curved surface having an arc shape. The cam 26 is provided with a fan-shaped projection 24 provided on the toothless portion 24a of the first separation / contact plate driving gear 24.
b, the toothless portion 24a of the one separation / contact plate driving gear 24
It is stuck to.

In this embodiment (2), the first planetary gear 22 rotates in the direction of arrow Z1 (the direction corresponding to the forward rotation of the paper feed roller 3), and as shown in FIGS. As shown, the contact point between the cam 26 and the protrusion 2b of the separation / contact plate 2a moves from P1 to P2, and the displacement δ of the protrusion 2b gradually changes. Thereby, the impact noise in the state where the paper is pressed against the paper feed roller 3 (the state of FIG. 9C) can be further reduced.

[0061]

As described above, according to the first aspect of the present invention, there is provided separation / contact plate driving means which operates in conjunction with the rotation of the paper feed roller, and the paper feed roller rotates in the paper feeding direction. The separation / contact plate driving means presses the paper against the paper feed roller by the separation / contact plate driving means when rotating forward (forward rotation), and the separation / contact plate driving means when the paper supply roller rotates in the opposite direction to the paper feeding direction (reverse rotation). The release plate releases the pressure between the paper and the paper feed roller,
This allows the paper and the paper feed roller to be pressed and released by the separation plate of the manual feed cassette by using the rotational force of the forward and reverse rotations of the paper feed roller without using the solenoid. There is an effect that the noise of the device can be reduced.

Further, since the paper is pressed against the paper feed roller at the same time as the paper feed operation, the paper is not pressed against the paper feed roller for a long time, and the paper tip is curled (deformed).
Thus, there is an effect that it is possible to perform good sheet feeding without causing jams and without causing jams.

Further, since the paper is pressed against the paper feed roller simultaneously with the paper feeding operation, the paper is not pressed against the paper feed roller for a long time, and the transfer of the rubber component of the paper feed roller to the paper is suppressed. Thus, there is an effect that the print quality at the leading edge of the paper is not deteriorated.

According to a second aspect of the present invention, in the paper feed mechanism of the image forming apparatus according to the first aspect, the separation / contact plate driving means includes a paper feed roller gear connected to the paper feed roller and the paper feed roller gear. A first planetary gear that meshes with the roller gear, a first separating / connecting plate drive gear that meshes with the first planetary gear when the paper feed roller rotates forward, a second planetary gear that meshes with the paper feed roller gear, and a reverse rotation of the paper feed roller The second separation / contact plate driving gear meshed with the second planetary gear is engaged with the first separation / contact plate driving gear and the second separation / contact plate driving gear, and the separation / contact plate is drivably engaged with the separation / contact plate. , And the separation / contact plate driving means can be constituted by using each gear and the cam, and there is an effect that the separation / contact plate can be smoothly driven by the cam.

According to a third aspect of the present invention, in a paper feeding mechanism of an image forming apparatus according to the first or second aspect, a cam,
Since the first separating / contacting plate driving gear and the second separating / contacting plate driving gear are arranged coaxially, the shape of the cam is simplified, and the cam, the first separating / contacting plate driving gear and the second There is an effect that the positional accuracy with the separation / contact plate driving gear can be improved.

According to the fourth aspect of the present invention, in the paper feed mechanism of the image forming apparatus according to the first to third aspects, the first separation / contact plate driving gear and the second separation / contact plate driving gear are the first separation / contact plate driving gear. Planetary gear and 1st
A toothless gear in which the engagement between the separation / contact plate driving gear and the second planetary gear and the second separation / contact plate driving gear is within a predetermined angle range, wherein the first planetary gear and the first separation / contact plate driving gear are at a predetermined angle; In this range, the cam is rotated by a predetermined angle to press the paper against the paper feed roller. Thereafter, the paper is in a free state without any mutual engagement. Further, the second planetary gear and the second separation / contact plate driving gear mesh with each other within a predetermined angle range, rotate the cam by a predetermined angle to release the pressing between the paper and the paper feed roller, and thereafter are in a free state without mutual mesh. Becomes Thereby, at the predetermined position of the separation / contact plate 2a (at least a position where the paper is pressed by the paper feed roller when the paper feed roller rotates forward, and at a home position when the paper feed roller rotates reversely). There is an effect that it can be easily stopped.

According to the fifth aspect of the present invention, in the paper feed mechanism of the image forming apparatus according to the first to fourth aspects, the cam is formed with a smooth curved surface at a portion which engages with the separation / contact plate. As a result, the paper is gradually pressed by the paper feed roller by the rotation of the cam, and the pressure between the paper and the paper feed roller is gradually released. As a result, the impact noise generated when the paper is pressed against the paper feed roller is reduced. There is an effect that can be further reduced.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing an image forming apparatus to which the present invention is applied.

FIG. 2 is a perspective view illustrating an embodiment (1) of a sheet feeding mechanism of the image forming apparatus according to the present invention.

FIG. 3 is a perspective view illustrating a separation plate of a sheet feeding mechanism of the image forming apparatus of FIG. 2;

FIG. 4 is a front view showing a separation plate of a sheet feeding mechanism of the image forming apparatus of FIG. 2;

FIG. 5 is a side view illustrating a separation plate driving unit and an operation of a sheet feeding mechanism of the image forming apparatus of FIG. 2;

FIG. 6 is a side view illustrating a separation plate driving unit and an operation of a sheet feeding mechanism of the image forming apparatus of FIG. 2;

FIG. 7 is a diagram illustrating an operation of a sheet feeding mechanism of the image forming apparatus of FIG. 2;

FIG. 8 is a diagram illustrating an operation of a sheet feeding mechanism of the image forming apparatus of FIG. 2;

FIG. 9 is a diagram illustrating an embodiment (2) of a sheet feeding mechanism of the image forming apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image forming apparatus 2 Manual feed cassette 2a Separation / contact plate 2b Projection 2d Spring 2e Paper guide 2h, 2i Projection 2j, 2k Side plate 2m, 2n hole 3 Paper feed roller 3a Shaft 4 Separation part 5 Paper detection sensor 5a Paper conveyance path 6 PS roller Pair 7 Printing section 8 Platen 9 Discharge roller 10 Paper feed mechanism 11 Separator plate driving means 11a Side plate 11b, 11c Oval hole 21 Feed roller gear 22 First planetary gear 23 Second planetary gear 24 First separator / contact plate drive gear 24a Missing tooth portion 25 Second detaching / contacting plate driving gear 25a Missing tooth portion 26 Cam A arrow B1, B2 arrow C1, C2 arrow D1, D2 arrow X1, X2 arrow Y1, Y2 arrow Z1, Z2 arrow W interval H Movement range P1 , P2 Contact point R Arrow θ Angle δ Displacement

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masanobu Exit 22-22, Nagaike-cho, Abeno-ku, Osaka City, Osaka F-term (reference) 2C058 AB16 AC07 AD01 AD03 AD04 AE02 AE10 AE13 AF04 AF09 AF17 AF20 AF25 AF31 JA04 JA12 JA18 3F343 FA02 FB03 FB04 FC17 FC28 GA04 GB01 GC01 GD01 HA25 HD10 HD18 HE16 KB04 LA02 LA15 LC12 LC22 LD04 LD24 LD26 MB02 MB09 MC20

Claims (5)

[Claims] A manual feed cassette for storing paper; and a paper feed roller unit for separating paper one by one from the manual feed cassette and feeding the separated paper to a paper transport path. In a paper feeding mechanism of an image forming apparatus provided with a release / contact plate capable of pressing and releasing the release / contact plate, a release / contact plate driving unit that operates in conjunction with rotation of a paper supply roller is provided, and the paper supply roller moves in a paper feeding direction. When the paper feed roller rotates in the normal direction (forward rotation), the release / contact plate driving means presses the paper against the paper roller, and when the paper feed roller rotates in the direction opposite to the paper feeding direction (reverse rotation), the release / contact plate drive is performed. A sheet feeding mechanism of the image forming apparatus, wherein the separation plate releases the pressing of the sheet and the sheet feeding roller by means. 2. A sheet feeding roller gear connected to a sheet feeding roller, a first planetary gear meshing with the sheet feeding roller gear, and a first planetary gear driven by a normal rotation of the sheet feeding roller. A first separating / contacting plate driving gear that meshes with the second feeder gear, a second planetary gear that meshes with the feed roller gear, a second separating / contacting plate driving gear that meshes with the second planetary gear by reverse rotation of the feeder roller, A driving gear and a cam engaged with the separation plate so as to be able to drive the separation plate while being driven in conjunction with the second separation plate driving gear, and the rotation of the cam drives the separation plate. The sheet feeding mechanism of the image forming apparatus according to claim 1, wherein: 3. The image forming apparatus according to claim 1, wherein the cam, the first separation / contact plate driving gear, and the second separation / contact plate driving gear are arranged coaxially. Paper feed mechanism. 4. The first separating / contacting plate driving gear and the second separating / contacting plate driving gear include a first planetary gear, a first separating / contacting plate driving gear, and a second
2. A toothless gear in which the engagement between the planetary gear and the second separation / contact plate drive gear is within a predetermined angle range.
3. The paper feeding mechanism of the image forming apparatus according to any one of 3. 5. The cam according to claim 1, wherein a portion of the cam that engages with the separation / contact plate has a smooth curved surface.
A sheet feeding mechanism for an image forming apparatus according to any one of the preceding claims.