JPH11263452A - Cassette tray - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cassette tray capable of delivering a record medium without biased delivery even when there is a little error in part precision. SOLUTION: A support plate 64 rising roughly at right angles respectively from both ends of one side part 62 of a middle plate is formed, and a slot 64a is formed on this support plate 64. The slot 64a extends in a direction orthogonal with the middle plate. A columnar projection 54a formed on a side wall is fitted in this slot 64a. Additionally, a pair of woodruff projections 62a circular arc parts 62b of which make contact with a bottom wall 52 is formed on a lower surface on a central part of the one side part 62 of the middle plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a cassette tray provided in an image forming apparatus such as a copying machine, a printer, and a plotter.

[0002]

2. Description of the Related Art As an output device of a computer or a work station, an ink jet type image forming apparatus for forming an image on a recording medium by discharging ink, or an electrophotographic type forming apparatus for forming an image on a recording medium using a developer or the like. Image forming apparatuses are known. These image forming apparatuses are usually provided with a cassette tray in which a plurality of recording media are stored in a stacked state. The cassette tray is incorporated in the main body of the image forming apparatus so as to be freely taken in and out, and the recording medium stored in the cassette tray is fed at a predetermined timing to an image forming unit on which an image is formed.

[0003] A cassette tray usually has a rectangular bottom wall, and includes a tub (frame) having an open upper surface, and a rectangular middle plate on which a recording medium is loaded. One side of the middle plate is positioned near the bottom wall of the tub and pivots, and the other side opposite to the one side is freely separated from and separated from the bottom wall of the tub. The tub is inclined with respect to the bottom wall.

A coil spring is disposed below the other side of the middle plate to bias the other side upward and away from the bottom wall of the tub to incline the middle plate. Further, above the other side of the middle plate, a paper feed roller for feeding out the recording medium loaded on the middle plate is arranged. With the middle plate loaded with the recording medium inclined with respect to the bottom wall of the tub, the top recording medium among the loaded recording media comes into contact with the above-mentioned paper feed roller, and the rotation of the paper feed roller As a result, the uppermost recording medium is sent from one side of the middle plate to the other side.

When a recording medium is loaded on the middle plate, the cassette tray is pulled out of the image forming apparatus, the middle plate is pressed down from above, and the whole middle plate is almost in contact with the bottom wall of the tub. Is locked by a locking member, and the recording medium is loaded. When the cassette tray is pushed into the image forming apparatus after the recording medium is loaded on the middle plate, the locking of the locking member is released, and the other side of the middle plate is urged upward by the coil spring. As a result, the inner plate is inclined with respect to the bottom wall of the tub,
The uppermost recording medium among the recording media loaded on the middle plate abuts on the above-mentioned paper feed roller, and as described above, the uppermost recording medium is moved along with the rotation of the paper feed roller. Is sent in a direction from one side to the other side.

[0006] As described above, the middle plate rotates from a position where the whole of the middle plate substantially contacts the bottom wall of the tub to a position where it is inclined with respect to the bottom wall of the tub. For this rotation, a pair of side plates, each of which is raised from the vicinity of both ends of one side of the middle plate and has a circular hole formed therein, and a pair of columnar projections fitted into the circular hole are formed. A pair of columnar projections fitted into the circular hole is formed on the side wall of the tub, and the intermediate plate rotates around the pair of columnar projections as a central axis.

By the way, the above-mentioned paper feed roller is usually
The two paper feed rollers are located inside both ends of the other side of the middle plate. Therefore, when the middle plate is inclined with respect to the bottom wall and the recording medium loaded on the middle plate is in contact with the paper feed roller, both ends of one side of the middle plate are fixed to the columnar projections. In this state, the inside of both ends of the other side of the middle plate is pressed against the paper feed roller via the recording medium.

[0008]

In such a state, when the recording medium is in contact with the two paper feeding rollers with the same force, the recording medium does not skew with the rotation of the two paper feeding rollers. Transported to However, due to the accuracy of the components of the middle plate and the accuracy of the attachment of the paper feed roller, the recording medium may not contact the two paper feed rollers with the same force. In this case, the middle plate tends to twist so that the recording medium comes into contact with the two paper feed rollers with equal force. However, even if the middle plate is twisted, the twist is limited, and the recording medium may not be able to abut against the two paper feed rollers with equal force. If the recording medium does not contact the two paper feed rollers with the same force, there is a problem that the recording medium is skewed when being fed.

SUMMARY OF THE INVENTION In view of the above circumstances, an object of the present invention is to provide a cassette tray from which a recording medium is fed without skew even if there is a slight error in the accuracy of parts and the like.

[0010]

According to the present invention, there is provided an image forming apparatus for forming an image on a recording medium, the cassette tray having a rectangular bottom wall and an open upper surface. And one side extending in a predetermined direction is located near the bottom wall, and the other side extending in the predetermined direction on the opposite side to the one side comes into contact with and separates from the bottom wall. And (1) the one side of the middle plate is provided with the supply medium, wherein the middle plate is provided with a recording medium fed in the sheet feeding direction from the one side to the other side. A first support member that supports the one side of the middle plate above the one side of the middle plate, which prohibits movement in the paper direction and allows the one side to move in a direction intersecting the paper feeding direction; 2) The one side of the middle plate is in the sheet feeding direction. So that it can move in the direction of the difference by a distance within a predetermined range, it is characterized in that a second supporting member supporting the one side portion in said plate from below.

Here, the first support member (3) rises and spreads from the vicinity of both ends of the one side of the middle plate.
It may be provided with a pair of support plates formed with a long hole extending in a direction perpendicular to the middle plate, and (4) a projection formed on the trough, which is fitted into the long hole.

The first support member includes: (5) a pair of support plates formed with outwardly protruding protrusions which rise from the vicinity of both ends of the one side of the middle plate and spread;
An elongated hole formed in the trough, in which the protrusion is movably fitted in a direction orthogonal to the middle plate, may be provided.

The second support member may further comprise: (7) the one side of the middle plate, wherein an arc portion slides on the bottom wall of the trough as the middle plate inclines with respect to the bottom wall. It may have a semilunar projection formed on the lower surface of the part.

Further, the second support member may be configured as (8)
A protrusion having a curved tip at the tip thereof, the protrusion moving along the bottom wall of the trough as the middle plate inclines with respect to the bottom wall; A curved receiving portion formed on the lower surface of the one side portion for receiving the protrusion may be provided.

Still further, the second support member is provided with (1)
0) It may be provided with a projection projecting from the bottom wall of the tub and supporting the one side of the middle plate from below.

Further, (11) the image forming apparatus is arranged above the other side portion of the middle plate, for sending out a recording medium stacked on the middle plate in a sheet feeding direction intersecting the predetermined direction. Having a pair of paper feed rollers,
(12) The second support member supports, from below, a central portion of the one side portion corresponding to a central portion sandwiched between the pair of paper feed rollers, of the other side portion, and the support region includes the pair of The area may be narrower than between the paper feed rollers.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the cassette tray according to the present invention will be described below with reference to the drawings.

FIG. 1 is a perspective view showing the appearance of a copying machine in which a cassette tray of the present invention is incorporated so as to be freely taken in and out.

On the top surface of a copying machine (which is an example of an image forming apparatus according to the present invention) 10, an original cover plate 12 which can be opened and closed is arranged. On the front side of the top surface, an operation panel display 14 for inputting the number of copies and the like is arranged.
The copying machine 10 is provided with a universal cassette (which is an example of a cassette tray according to the present invention) 16 in which a plurality of cut sheets are stored so as to be able to be taken in and out of the main body of the copying machine 10. The right side wall of the copying machine 10 is provided with a rectangular manual tray 18 (see FIG. 2) capable of feeding small-size recording paper such as postcards. As shown in FIG. 2, the manual feed tray 18 rotates around the lower side 18a in the direction of arrow C and opens to a position where a recording medium can be placed (a position indicated by a two-dot chain line). The left side wall of the copying machine 10 is provided with a paper discharge tray 20 on which recording paper on which an image is formed is stacked.

At the front of the copier 10, a rectangular front door 22 is provided.
However, it is fixed so that it may open to the near side with the lower side portion 22a as the center of rotation. By opening the front door 22, the inside of the copier 10 can be observed. Further, with the front door 22 kept open, a hook (not shown) disposed near the front door 22 is removed, so that a repulsive force of a damper (not shown) causes the upper portion of the main body of the copying machine 10 ( The front side portion of the optical system 28 and the photosensitive drum 32 described later) is pushed up. As a result, the copying machine 10 is divided into an upper body and a lower body (a part in which the universal cassette 16 and the like are incorporated).

Referring to FIG. 2, a procedure for forming an image by the copying machine 10 of FIG. 1 will be described.

FIG. 2 is a schematic diagram showing an outline of the internal structure of the copying machine 10. As shown in FIG. 2, the same components as those of FIG. 1 are denoted by the same reference numerals.

An original platen glass 26 on which the original 24 is placed is disposed below the original cover 12. The original 24 is placed on the original platen glass 26 so that the image surface faces downward, and the original 24 is pressed and fixed by the original cover 12. The image recorded on the document 24 is read by a well-known optical system 28 having a light source lamp (not shown) or the like, and light (broken line A) carrying information of the image recorded on the document is obtained.
This light is applied to the photosensitive drum 32 uniformly charged by the charging unit 30 to form an electrostatic latent image. This electrostatic latent image is developed with the developer (toner) supplied from the developing unit 34 to form a developed image. On the other hand, a recording medium such as recording paper is fed in the direction of arrow B from the universal cassette 16, and the developed image is transferred to the recording medium in the transfer unit 36. The recording medium to which the developed image has been transferred is transported to the fixing unit 40 by the transport unit 38. A heat roller 42 and a press roller 44 are disposed in the fixing unit 40. The recording medium is conveyed while being sandwiched between these two rollers 42, 44, and the developed image is fixed on the recording medium. The recording medium on which the developed image has been fixed in this manner is discharged and stacked on the discharge tray 20. The toner remaining on the photosensitive drum 32 after the transfer is scraped off by the cleaning device 46. In addition, the recording medium can be fed from the manual feed tray 18, and the procedure for forming an image on the recording medium fed from the manual feed tray 18 is the same as described above.

The general structure of the universal cassette 16 will be described with reference to FIGS.

FIG. 3 is a perspective view showing the universal cassette with the middle plate lowered, and FIG. 4 is a perspective view showing the universal cassette with the middle plate raised. FIG. 5 is an enlarged plan view showing a middle plate of the universal cassette in a state where the middle plate is raised and a portion in the vicinity thereof, and FIG. 6 is a perspective view showing a sheet feeding roller and a portion in the vicinity thereof. The universal cassette 16 shown in these figures
Are the same, but there are some which are slightly different in shape, even if they are the same, because they show a schematic configuration.

The universal cassette 16 stores the copy machine 10
(See FIGS. 1 and 2). The universal cassette 16 includes a trough 50 having a rectangular bottom wall 52 and a side wall 54 rising from the peripheral edge of the bottom wall 52. On the bottom wall 52 of the tub 50, a rectangular middle plate 60 which is about half the size of the bottom wall 52 and on which a recording medium is loaded is arranged. The recording medium loaded on the middle plate 60 is sent out in the direction of arrow E.

One side 62 of the middle plate 60 extends in the direction of arrow D, and is located near the center of the bottom wall 52 in the direction of arrow E. At both ends of this one side 62 in the direction of arrow D, a support plate 64 rises substantially at right angles from the one side 62. A long hole 64a is formed in the upper portion of the support plate 64, and a protrusion 54a (see FIG. 7) formed on the side wall 54 is fitted into the long hole 64a. Therefore, the middle plate 60 can rotate between the position shown in FIG. 3 and the position shown in FIG. 4 around the projection 54a as a rotation axis. Slot 6
4a will be described later with reference to FIG.

On the side opposite to one side 62 of the middle plate 60, another side 66 is formed which extends in the direction of arrow D and which comes into contact with and separates from the tip of the bottom wall 52 in the direction of arrow E. Below the central portion of the other side 66, two coil springs 69 (only one is shown in FIG. 6) are arranged. The upper ends of the two coil springs 69 are fixed to the center of the other side 66, and the lower ends are fixed to the bottom wall 52. The central portion of the other side 66 of the middle plate 60 is constantly urged upward by these two coil springs 69. Thus, the other side 66 of the middle plate 60
The middle plate 60 is inclined upward with respect to the bottom wall 52 by being urged upward to be pushed up and the one side 62 rotating near the bottom wall 52.

The middle plate 60 has four rectangular openings 68 formed therein. These openings 68 are for movement of side regulation plates 70 that regulate both ends of the recording medium loaded on the middle plate 60. The side regulating plate 70 includes a pair of L-shaped plates 70a and 70b, and is fixed to the bottom wall 52 so as to be movable in the direction of arrow D. These pair of plates 70a,
70b moves in the direction of arrow D in conjunction with it, and its position can be changed according to the size of the recording medium. Accordingly, by moving the pair of plates 70a and 70b to an appropriate position in accordance with the size of the recording medium, the middle plate 60 can record one type of recording medium of a plurality of types of recording media. Media can be loaded selectively.

When the pair of plates 70a and 70b are moved, the V-shaped size switching knob (not shown) is moved while being pinched. When the size switching knob is released when the pair of plates 70a and 70b are located at predetermined positions, the tip of the size switching knob is fitted into a hole (not shown) formed in the bottom wall 52, and the predetermined position is adjusted. A pair of plates 70
a, 70b are fixed.

A rear end regulating plate 80 is disposed on the bottom wall 52 near the center of one side 62 of the middle plate 60. The rear end regulating plate 80 moves in the direction of arrow F in conjunction with the movement of the middle plate 60, and regulates the rear end of the fed recording medium.

A pair of plates 70 constituting the side regulating plate 70
As shown in FIG. 6, an L-shaped separation claw 90 (not shown in FIGS. 3 and 4) is fixed to each of a and 70b, and moves together with the pair of plates 70a and 70b. Further, the distal end portion 90a of the separation claw 90 is bent to feed the recording medium loaded on the middle plate 60 (direction of arrow E).
Both ends of the tip are pressed from above. As will be described later, when the top one of the recording media stacked on the middle plate 60 is sent out with the rotation of the paper feed roller 100, the tip of the topmost recording medium is It is separated from the leading end portion 90a and separated from the second and subsequent recording media from the top.

Above the other side 66 of the middle plate 60, as shown in FIGS.
Are arranged, and both ends in the longitudinal direction of the rotating shaft 110 are rotatably fixed to the main body of the copying machine 10 (see FIG. 2). A pair of paper feed rollers 100 are fixed to the rotating shaft 110. The pair of paper feed rollers 100 has a half-moon shape, and is fixed to a portion that is approximately one third of the length of the rotating shaft 110 from each of both longitudinal ends of the rotating shaft 110. The rotation shaft 110 normally stops in a state in which the paper feed roller 100 is up, that is, in a state in which the arc-shaped portion 100a of the paper feed roller 100 is located on the side opposite to the intermediate plate 60 with the rotation shaft 110 interposed therebetween. ing. On the basis of a control signal from a control device (not shown) built in the copying machine 10 (see FIG. 2), the rotation shaft 110 is turned at a predetermined timing by an arrow G.
One turn in the direction. In addition, a separation sheet 67 for facilitating separation of the recording medium stacked on the middle plate 60 is attached to a portion of the middle plate 60 corresponding to a portion below the sheet feeding roller 100.

The middle plate 6 which is almost entirely in contact with the bottom wall 52
When the universal cassette 16 is pushed into the main body of the copier 10, the other side 66 of the middle plate 60 is pushed up, and as shown in FIG.
Are inclined with respect to the bottom wall 52. When the rotation shaft 110 rotates at the above-described predetermined timing, the top one of the recording media stacked on the intermediate plate 60 abuts against the arc-shaped portion 100a of the paper feed roller 100, and the rotation causes the arrow E Sent in the direction. When the uppermost recording medium starts to be fed, both ends of the leading end of the uppermost recording medium come off the leading end 90a of the separation claw 90, and are separated from the second and subsequent recording media from the top.

By the way, in the above example, the recording medium is sent out in the direction of arrow E by the rotation of the arc-shaped portions 100a of the two paper feed rollers 100 while contacting (contacting) the recording medium. In this case, if the two sheet feed rollers 100 have the same contact force when they are in contact with the recording medium, the recording medium is sent straight without skew. Therefore, the copying machine 10 is designed so that each of the two paper feed rollers 100 comes into contact with the recording medium with the same contact force. However, the two coil springs 69
Due to the urging force (spring pressure), the mounting error of the rotating shaft 110, or the like, the two paper feed rollers 100 may not contact with the recording medium with the same contact force. In this case, the recording medium is skewed while being sent out from the universal cassette 16, causing a paper jam (jam) or the like. Universal cassette 16 of the present embodiment
In this case, the recording medium can be sent out without skewing even if there is some error in the accuracy of the parts.

With reference to FIGS. 7 to 10, a description will be given of a technique for feeding a recording medium without skew.

First, referring to FIG. 7, the structure near one side 62 of the middle plate 60 will be described.

FIGS. 7A and 7B are side views schematically showing the vicinity of one side portion 60 of the middle plate 60. FIG. 7A shows a state in which the middle plate 60 is pushed down and is substantially parallel to the bottom wall 52. Show,
(B) shows a state where the middle plate 60 is pushed up and inclined with respect to the bottom wall 52.

As described above, the support plate 64 rises at substantially right angles from both ends of the one side portion 62, and the support plate 64 is formed with the long hole 64a. Slot 64
a extends in a direction orthogonal to the middle plate 60. The long hole 64a has a columnar projection 54a formed on the side wall 54.
Is fitted. Long hole 64a and cylindrical projection 54a
For example, the diameter of the long hole 64a in the longitudinal direction is about three times the outer diameter of the projection 54a, and the short diameter of the long hole 64a is substantially the same as the outer diameter of the projection 54a. Therefore, the projection 54a can move in the long hole 64a in the longitudinal direction. For this reason, although the middle plate 60 rotates about the projection 54a as a rotation axis, the one side 62 moves during the rotation of the middle plate 60 or after the rotation by the length in the longitudinal direction of the long hole 64a. it can. That is, the one side 62 of the middle plate 60 is orthogonal to the middle plate 60 (an example of a direction intersecting the sheet feeding direction according to the present invention) by the protrusion 54a fitted into the long hole 64a and the support plate 64. In the paper feeding direction.

A pair of half-moon-like projections 62a are formed on the lower surface of the central portion of one side 62 of the middle plate 60. The arc-shaped portions 62b are in contact with the bottom wall 52. The arc-shaped portion 62b remains in contact with the bottom wall 52 due to the weight of the middle plate 60 and the weight of the recording medium loaded on the middle plate 60. For this reason, even if the middle plate 60 rotates about the projection 54 a as a rotation axis, the central portion of one side 62 of the middle plate 60 is about the radius of the arc-shaped portion 62 b in a direction perpendicular to the bottom wall 52 (in the present invention). (An example of a distance within the predetermined range). Also,
The arc-shaped portion 62b has a bottom wall that is substantially parallel to the bottom wall 52 (in the direction indicated by the arrow F in the sheet feeding direction or the opposite direction) as the middle plate 60 rotates about the projection 54a as a rotation axis. Slide 52.

Here, the position of the pair of crescent-shaped projections 62a will be described with reference to FIG. 5 again.

With reference to a virtual line segment H that divides the middle plate 60 into two in the direction of arrow D, each of the pair of paper feed rollers 100 is fixed at a position separated from the line segment H by a distance L1. In this case, each of the pair of semilunar protrusions 62a is
It was formed at a position away from the line segment H by a distance L2. Distance L
2 is shorter than the distance L1. In this manner, here, the pair of sheet feeding rollers 1 of the other side 66 of the middle plate 60 are used.
A pair of crescent-shaped projections 62a are arranged in a region narrower than the central portion sandwiched between 00 and so as to support the central portion of one side 62 from below. As a result, both end portions of the one side portion 62 move easily, and the recording medium is
Therefore, even if there is a difference in the contact force of contacting the two sides, both end portions of the one side portion 62 easily move to cancel the difference. A projection 54a is formed on the support plate 64, and the projection 54a
The side wall 54 may be formed with a long hole 64a into which the hole is fitted.

Referring to FIG. 8 to FIG.
The state in which is rotated will be described.

FIG. 8 is a schematic diagram showing a state in which the range in which the middle plate can rotate is viewed from the side. FIG. 9 is a side view showing a state where the middle plate is pushed down to the bottom wall, and FIG. 10 is a side view showing a state where the middle plate is pushed up. In these figures, the same components as those shown in FIGS. 5 to 7 are denoted by the same reference numerals.

Copy the universal cassette 16 to the copying machine 10
When the middle plate 60 is pulled out from the main body (see FIG. 1) and pressed down, the middle plate 60 is fixed at a position substantially parallel to the bottom wall 52. When the universal cassette 16 is pushed into the main body of the copying machine 10, the intermediate plate 60 is pushed up to a position inclined with respect to the bottom wall 52 by the urging force of the coil spring 69. Therefore, the middle plate 60 rotates between the position indicated by the solid line in FIG. 8 and the position indicated by the dashed line. The separation claw 9
Numeral 0 is supported by the support plate 92 so as to rotate slightly with the rotation of the middle plate 60.

As shown in FIG. 9, the recording medium is loaded with the middle plate 60 fixed at a position substantially parallel to the bottom wall 52. Thereafter, when the universal cassette 16 is pushed into the main body of the copying machine 10, the middle plate 60 is pushed up, as shown in FIG. It comes in contact with a paper feed roller 100 (only one is shown in the figure). When two portions of the recording medium stacked on the intermediate plate 60 abut against each of the two paper feed rollers 100, if the abutting forces at the two locations are different from each other due to, for example, an error in the accuracy of the components, the feeding may fail. The middle plate 60 tends to be twisted in an intersecting direction that intersects the paper direction (the arrow F direction).

However, when the projection 54a moves in the elongated hole 64a, both end portions of the one side 62 supported by the support plate 64 and the projection 54a can move in the above-described cross direction. For this reason, these two end portions move in the above-described cross direction in accordance with the contact forces at the above-mentioned two places, and the twisting of the middle plate 60 can be prevented. In addition, since the elongated holes 64a and the protrusions 54a prohibit both end portions from moving in the paper feeding direction, the middle plate 60 does not bend in the paper feeding direction. Further, since the crescent-shaped projection 62a supports the both ends so as to be able to move in the cross direction by a distance within a predetermined range, only one of the two ends can move extremely in the cross direction. Therefore, the middle plate 60 is prevented from tilting in the cross direction. As a result, the contact force at the two positions on the recording medium that comes into contact with the sheet feeding roller 100 is substantially equal, and the medium plate 60 is not not only twisted but also does not bend in a direction intersecting the sheet feeding direction. There is no oblique feeding (skew).

It is to be noted that the same function can be obtained even if the bottom plate 52 is provided with a projection having a concave receiving portion for holding one side portion 62 of the middle plate 60 without providing the semi-lunar projection on the middle plate. 2
A support member can be obtained.

Referring to FIG. 11, one side 62 of middle plate 60
The other example of the support member which supports from below is shown.

FIG. 11 is a side view showing a supporting member for supporting one side 62 of the middle plate 60 from below, and FIG. 11A is a side view showing a state where the middle plate 60 is substantially parallel to the bottom wall 52. FIG. 4B is a side view showing a state where the middle plate 60 is inclined with respect to the bottom wall 52.

The support member 120 includes a support table 130 having a projection 132 having a curved tip 134 and a support block 140 having a curved receiving portion 142 for receiving the curved tip 134. ing. Support table 1
30 is fixed to the bottom wall 52 so as to be movable in the direction of arrow F as the middle plate 60 inclines (rotates) with respect to the bottom wall 52. The support block 140 is fixed to the lower surface of the one side 62. Even if the support member 120 having the above-described configuration is used instead of the semilunar projection 62a shown in FIG. 7, the same operation and the same effect as the semilunar projection 62a can be obtained.

In the above example, the semilunar projection 62a
Although the configuration in which the central portion of one side 62 of the middle plate 60 is supported by the support member 120 and the support member 120, the configuration may be such that both ends of the one side 62 are supported. In the above-described example, the universal cassette has been described. However, the present invention can be applied to a cassette tray that can accommodate only one type of recording medium.

[0053]

As described above, according to the cassette tray of the present invention, when two paper feed rollers are disposed above the other side of the middle plate, each of the two paper feed rollers has:
Two portions of the recording medium loaded on the middle plate come into contact with each other. At this time, if the contact forces at the two locations are different from each other due to, for example, an error in the accuracy of the parts, the middle plate tends to twist in an intersecting direction intersecting the sheet feeding direction. However, since one side supported by the first support member can move in the above-described cross direction, this one side moves in the above-described cross direction in accordance with the contact force at the above-mentioned two places, and the twist of the middle plate is reduced. Can be prevented. Moreover, since the first support member prohibits the one side portion from moving in the paper feeding direction, the middle plate does not bend in the paper feeding direction. Further, since the second support member supports the one side so as to be movable in the cross direction by a distance within a predetermined range, the one side does not move extremely in the cross direction, and The board is prevented from tilting in this cross direction. As a result, the contact forces at the two locations are substantially equal, and the medium plate is not twisted and does not bend in the direction intersecting the sheet feeding direction, so that the recording medium is not sent obliquely (skewed). .

Here, the first support member is fitted into the pair of support plates having elongated holes extending in a direction perpendicular to the intermediate plate, the first support members rising from the vicinity of both ends of one side of the intermediate plate and expanding. In addition, in the case where the first support member is provided with the protrusion formed in the tub, the first support member having a relatively simple configuration can be obtained.

Further, the first support member rises and spreads from the vicinity of both ends of one side of the middle plate and has a pair of support plates formed with outwardly protruding protrusions, and the protrusion moves in a direction perpendicular to the middle plate. In the case where the first support member is provided with a long hole formed in the tub, which is freely fitted, a first support member having a relatively simple configuration can be obtained as in the above configuration.

Further, an arc portion slides on the bottom wall of the tub as the middle plate inclines with respect to the bottom wall.
In the case of having a half-moon-shaped projection formed on the lower surface of one side of the middle plate, the second support member slides on the bottom wall.
Wear of the middle plate can be prevented.

Further, the second support member includes a protrusion having a curved tip at the tip thereof, the second support member moving along the bottom wall along the bottom wall of the tub as the middle plate inclines with respect to the bottom wall. In the case where the intermediate plate has a curved receiving portion formed on the lower surface of one side portion for receiving the projection, the projection and the receiving portion are worn with the rotation of the intermediate plate, but the bottom wall and Wear of the middle plate can be prevented.

Further, when the second support member has a projection protruding from the bottom wall of the tub and supporting one side of the middle plate from below, it is possible to prevent the bottom wall from being worn.

Further, the image forming apparatus has a pair of paper feed rollers disposed above the other side of the middle plate for feeding out the recording medium loaded on the middle plate in a paper feed direction intersecting a predetermined direction. A second supporting member for supporting, from below, a central portion of one side corresponding to a central portion sandwiched between the pair of paper feeding rollers of the other side, and a supporting region of which corresponds to the pair of paper feeding rollers. If the area is narrower than the gap between the rollers, the both ends of one side are easy to move, and even if a difference occurs in the contact force of the recording medium abutting on the pair of paper feed rollers, the one side is so adjusted as to cancel the difference. Will move easily.
That is, since the middle plate easily follows the inclination of the sheet feeding roller, the skew can be prevented more reliably.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a copying machine in which a cassette tray of the present invention is incorporated so as to be freely taken in and out.

FIG. 2 is a schematic diagram showing an outline of an internal structure of the copying machine shown in FIG. 1;

FIG. 3 is a perspective view showing the universal cassette with the middle plate lowered.

FIG. 4 is a perspective view showing the universal cassette with the middle plate raised.

FIG. 5 is an enlarged plan view showing a middle plate of the universal cassette in a state where the middle plate is raised and a portion in the vicinity thereof;

FIG. 6 is a perspective view illustrating a sheet feeding roller and a portion near the sheet feeding roller.

FIGS. 7A and 7B are side views schematically showing the vicinity of one side of the middle plate, wherein FIG. 7A shows a state where the middle plate is pushed down and is substantially parallel to the bottom wall, and FIG. The state in which the middle plate is pushed up and inclined with respect to the bottom wall is shown.

FIG. 8 is a schematic diagram showing a state in which the range in which the middle plate can rotate can be viewed from the side.

FIG. 9 is a side view showing a state where the middle plate is pushed down to the bottom wall.

FIG. 10 is a side view showing a state where the middle plate is pushed up.

FIGS. 11A and 11B are side views showing a support member that supports one side of the middle plate from below, where FIG. 11A is a side view showing a state where the middle plate is substantially parallel to the bottom wall, and FIG. It is a side view showing the state where the middle board was inclined to the bottom wall.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Copier 54a Projection 60 Middle plate 62a Half-moon-shaped member 62b Arc-shaped part 64 Support plate 64a Slot 120 Support member 130 Support stand 132 Projection 134 Tip 140 Support block 142 Receiving part

Claims (7)

[Claims] 1. An image forming apparatus for forming an image on a recording medium, wherein a tub having a rectangular bottom wall, an upper surface of which is open, and a side extending in a predetermined direction are located near the bottom wall. The other side extending in the predetermined direction on the side opposite to the one side is inclined with respect to the bottom wall by coming into contact with and separating from the bottom wall, and is supplied in a sheet feeding direction from the one side to the other side. A cassette tray including a middle plate on which a recording medium to be printed is stacked, wherein the one side of the middle plate is prohibited from moving in the paper feeding direction and the one side intersects the paper feeding direction. A first support member that supports the one side of the middle plate above the first plate, and a distance within a predetermined range in a direction in which the one side of the middle plate intersects the paper feeding direction. So that it can move only one side of the middle plate. The cassette tray which is characterized in that a second support member for supporting from below. 2. The first support member comprises: a pair of support plates, each of which has a long hole extending in a direction perpendicular to the middle plate and rising and expanding from near both ends of the one side of the middle plate; The cassette tray according to claim 1, further comprising: a projection formed on the trough, which is fitted into the hole. 3. The first support member includes: a pair of support plates having protrusions protruding outwardly, the support plates rising from the vicinity of both ends of the one side of the middle plate, and extending in a direction perpendicular to the middle plate. 2. The cassette tray according to claim 1, further comprising an elongated hole formed in said trough, wherein said projection is movably fitted into said tray. 4. The lower surface of the one side of the middle plate, wherein an arc portion slides on the bottom wall of the trough as the middle plate inclines with respect to the bottom wall. 4. A cassette tray for recording paper according to claim 1, further comprising a half-moon-shaped projection formed on said recording medium. 5. The second support member moves the bottom wall of the trough along the bottom wall as the middle plate inclines with respect to the bottom wall. And a curved receiving portion formed on a lower surface of the one side portion of the middle plate for receiving the projection. Cassette tray for recording paper. 6. The device according to claim 1, wherein the second support member includes a protrusion protruding from the bottom wall of the tub and supporting the one side of the middle plate from below. Or 3, a cassette tray for recording paper. 7. The image forming apparatus according to claim 1, further comprising: a pair of feeders disposed above the other side of the middle plate, for feeding a recording medium stacked on the middle plate in a sheet feeding direction intersecting the predetermined direction. A paper roller, wherein the second support member supports, from below, a central portion of the one side portion corresponding to a central portion sandwiched between the pair of paper feed rollers, of the other side portion, 7. The support area is a narrower area than between the pair of paper feed rollers.
A cassette tray according to any one of the preceding claims.