JP2705037B2 - Image forming device - Google Patents

Description

The present invention relates to an image forming apparatus having a plurality of sheet stacking cassettes. More specifically, the present invention relates to a case in which a box type cassette containing a large number of sheets is stored in an image forming apparatus main body. The present invention relates to a sheet feeder that is arranged and feeds a desired sheet material by selecting a cassette in which the sheet material is stacked and moving the cassette to a sheet feeding unit.

2. Description of the Related Art Conventionally, as a sheet feeding method in an image forming apparatus such as a copy drawing, a sheet material of a required paper size or type is loaded from a plurality of cassettes loaded with the sheet material. Cassette, and remove one sheet from this cassette.
An automatic feeding method for feeding sheets one by one to the image forming unit of the apparatus main body and a so-called manual sheet feeding method for manually feeding an arbitrary sheet material are provided.

FIG. 12 shows an example of an image forming apparatus provided with a sheet feeding device based on the above automatic feeding method.

In FIG. 12A, the apparatus main body 2 of the image forming apparatus 1
An optical system 3 for manipulating a document (not shown) and a photosensitive drum (hereinafter, referred to as an image forming unit) 5 which is exposed by the optical system 3 to form a latent image are provided therein. The toner image formed by the development is transferred to a sheet material fed to the image forming unit 5. In the image forming apparatus 1, a plurality of cassettes a and b on which sheet materials P are stacked are mounted from the side of the apparatus main body 2. The sheet material P fed from one of the cassettes a and b is conveyed to the image forming unit 5 to form an image.

The image forming apparatus 1 shown in FIG. 12 (b) has a plurality of cassettes a and b in the apparatus main body 2 and a cassette in the cabinet 2a.
This is a method in which c and d are put in and out from the front side of the apparatus main body 2. In recent years, this method is more prevalent than the method shown in FIG. In the case of FIG. 12, four cassettes a to d are arranged downstream of the image forming unit 5, and sheet materials P of various sizes or paper types are arranged in each cassette. The sheet material P is fed one by one from the cassette selected by the operator to the image forming unit 5 of the apparatus main body 2.

Further, in recent years, there has been a strong demand for an increase in the number of sheets P to be stored with the speeding up of the copying machine, and as shown in FIG. 12 (c), two-stage cassettes a and b provided in the cabinet 2a. That can store a large amount of single type sheet material P in addition to
The image forming apparatus 1 having a C ₀ is also used. However, as the number of stored sheets P increases, the sheet P
There is also a strong demand for diversification of types and sizes, and the configuration shown in FIG. As a result, in order to obtain a sheet material P of a desired size (or paper type), the operator has to perform a complicated manual operation of exchanging a plurality of cassettes storing the sheet materials P of each size.

In order to store a large amount of various types of sheet materials P, an image forming apparatus (see FIG. 13) has been proposed, for example, as described in the specification and drawings of Japanese Utility Model Application Laid-Open No. 52-36930. . In the figure, a plurality of cassettes 101a to 101d are arranged in a substantially vertical direction in a cabinet 2a provided below the apparatus main body 2, and a sheet material P conventionally stored in a horizontal state is set in a vertical direction. In the image forming apparatus 1, the cassettes 101a to 101d are arranged as described above, so that the space of the apparatus main body 2 is reduced to the sheet material P.
It was intended to be used effectively for storage.

In this apparatus, a carriage 102 accommodating a plurality of cassettes 101a to 101d moves in the front-rear direction in the apparatus main body 2 and sets a selected cassette to a sheet feeding position corresponding to a sheet feeding roller 103. Further, a cassette selected by a lifter mechanism (not shown) provided in each apparatus main body 2 is raised to a position shown by a chain line in FIG. Paper feed roller 103
Is that the lever 105 pivotally supporting it swings in conjunction with the lever 107 which swings by the rotation of the eccentric cam 106, so that the sheet P is brought into and out of contact with the sheet P and the image in the apparatus main body 2 is moved. The sheet is fed to the forming unit 5. The image forming apparatus shown in FIG.
The only feed roller 10 that feeds the sheet material P
This is done by 3.

(C) Problems to be Solved by the Invention However, in the conventional apparatus shown in FIG. 13, a driving system for moving the carriage 102 to select the cassettes 101a to 101d, and a further selected cassette, for example, a cassette A drive system for pulling up 101a to the position of paper feed roller 103 is required. For this reason, a complicated operation system is required for the cassette to move in the horizontal direction and the vertical direction in the figure after the operator selects the cassette and before the selected cassette is set to the manual position. , And the waiting time of the operator is further increased.

Further, in the above-mentioned conventional apparatus, as shown in FIG. 14, the cassette 101a for storing the sheet material P has a mechanism having a middle plate 110 at the bottom of the cassette. By pressing and biasing the sheet material P to the left (in the drawing), the sheet feeding surface of the sheet material P is kept constant. However, in this method, the spring 109 and the middle plate 110 are considerably displaced in the depth direction of the cassette. One of the objectives of storing sheets in an upright position (upright position) is to save space, increase the size of the apparatus, and require a long replacement time for cassette selection. It is disadvantageous for "storage of materials".

Furthermore, according to experiments by the inventor of the present application, various commonly used sheet materials having different thicknesses, sizes, and paper types are held in an upright state, particularly in a high-temperature and high-humidity environment. It has been confirmed that a buckling phenomenon occurs with time in the sheet material due to its own weight. In this state, it is no longer possible to reliably feed the sheet material P by the feed roller 103.

Therefore, the present invention provides a first moving unit that positions a desired cassette among a plurality of cassettes near a paper feeding unit;
The second moving means for moving the selected cassette to the paper feeding means can be driven by the same drive source, and the paper feeding means is previously set in the paper feeding position when the cassette is set in the paper feeding means. It is an object of the present invention to provide an image forming apparatus in which the above-described setting operation of the cassette is enabled by retreating the cassette.

Further, according to the present invention, the sheet material in each cassette is pressed and held by a buckling prevention means to prevent buckling of the sheet material due to a change with time, thereby realizing stable image formation. It is intended to provide a device.

(D) Means for Solving the Problems According to the invention according to claim 1, a plurality of cassettes accommodating a sheet material, and the cassettes are supported in a standing state inclined at a certain angle,
A carriage capable of moving back and forth in a horizontal direction on a fixed base; a driving unit for driving the carriage; and an inclined surface provided on the fixed base side for selectively pushing up the carriage in accordance with the movement of the carriage. And a sheet feeding means for feeding the sheet material from the cassette pushed up by the inclined surface to the image forming section.

The invention according to claim 2, wherein a plurality of seats for pressing and holding the sheet material surface to prevent buckling of the sheet material caused by the sheet material stored in each of the cassettes being in an upright state. A buckling prevention means, and a contact / separation mechanism for releasing the buckling prevention means of the selected and pushed-up cassette from pressing the sheet material at the time of feeding from the cassette.

According to a third aspect of the present invention, the plurality of cassettes are inclined at an appropriate angle θ with respect to a direction perpendicular to the direction of movement by the driving means, and the sheet surface of the selected cassette is supplied to the plurality of cassettes. The inclination angle of the inclined surface, which is moved to the paper feeding position of the paper means, from the horizontal plane substantially coincides with the vertical direction of the sheet surface of the sheet material.

(E) Operation Based on the above configuration, when the cassette containing the desired sheet material is selected and the drive source is activated, the cassette is moved in a substantially horizontal direction by the drive means, and the selected cassette is moved to the paper feed means. Located below.

When the selected cassette is moved in the horizontal direction to the position of the sheet feeding means by the driving means, the cassette is pushed upward by the inclined surface of the push-up member and moves to the sheet feeding position of the sheet feeding means. Since the upward movement of the cassette is performed by pushing up the cassette corresponding to the sheet feeding means by the movement of the carriage by the driving means, and the inclined surface of the member is pushed up, a special driving means for moving the cassette upward is provided. In this state, the selected cassette can be set at the position where the sheet can be fed, and in this state, the sheet feeding unit is positioned from the retracted position to the sheet feeding position and feeds the sheet.

Well, buckling is likely to occur due to the sheet material in each cassette being in an upright position, but this sheet material is pressed by buckling prevention means, which makes it possible to load the sheet material over time. The resulting buckling is prevented. Further, at the time of feeding the selected cassette, the action of the buckling prevention means is released by the contact / separation mechanism, so that the sheet material is not subjected to the load from the buckling prevention means, and Paper is fed stably.

Further, when the selected cassette is moved to the sheet feeding means by the push-up member, the cassette moves upward in the same direction as the direction perpendicular to the sheet surface of the sheet material stored in the cassette. The sheet material is brought into contact with the sheet feeding means at a predetermined position from the leading end thereof without being affected by the storage amount of the sheet material therein, and stable sheet feeding is performed.

(F) Example Hereinafter, an example of the present invention will be described with reference to the drawings.

FIG. 1 shows an image forming apparatus 1 including a copying machine to which the present invention is applied. The image forming apparatus 1 includes an apparatus main body 2 having an image forming unit described later,
And a cabinet 2a in which a vertical paper feed unit described later is stored.

A first optical system 3 for scanning a document (not shown) placed on a document table 7 and a photosensitive drum (image forming unit) 5 located below the first optical system 3 are provided in an upper portion of the apparatus main body 2. Have been. The first optical system 3 includes a lamp 9 for irradiating the original, a movable mirror 10, a plurality of reflection mirrors 11, a lens 12, and the like. The image light L reflected from the original is projected onto the image forming unit 5. The light is emitted to cause the image forming unit 5 to form a latent image. Below the optical system 3, a second optical system 13 that outputs image light L corresponding to a signal input from a contra-roller (not shown) is provided. The forming section 5 forms a latent image. The toner image formed by developing the latent image is transferred to a sheet material P fed as described later by a transfer charger 15, and the transferred sheet material P is fixed by a fixing device 16. The sheet is discharged out of the apparatus by a pair of sheet discharge rollers 17.

The feeding of the sheet material P to the image forming unit 5 as the image forming unit is performed by the horizontal sheet feeding unit 21 including the cassettes 19 and 20 and the sheet feeding roller in the apparatus main body 2, the vertical sheet feeding unit 6 or Paper is fed from either the manual paper feed unit 22. The sheet material fed from the horizontal paper feed unit 21 and the vertical paper feed unit 6 is transported to the image forming unit 5 by the transport roller material 23.

The vertical paper feed unit 6 houses a carriage 27 that can move a fixed base 25 in the cabinet 2a in the directions of arrows 26a and 26b by an operation described below, and a plurality of sheet materials P, respectively. Cassettes 29,3
0, 31, 32, and a paper feed roller (paper feed means) 33 for feeding the sheet material P in one of the cassettes 29 to 32 selected as described later. In addition, each cassette way 29-32
Are arranged in a vertical state in which each is inclined by an angle θ with respect to a direction (straight line V) perpendicular to the traveling direction of the carriage 27.

Here, when the operator selects a desired cassette in the vertical paper feed unit 6, it is necessary to move the selected cassette to below the paper feed roller 33. At that time, feed roller 33
Is an obstacle to the movement of the moving cassettes 29 to 32, it is necessary to retract the paper feed roller 33 from the illustrated paper feed position to a retracted position (non-paper feed position) in the direction of arrow 35. A release mechanism for retracting the paper feed roller 33 will be described with reference to FIG.

FIG. 2 shows a release mechanism (release means) 36 for moving the paper feed roller 33 from the paper feed position to the retracted position.

In the figure, a support shaft 37a is rotatably supported by the cabinet 2a and is connected to a drive source (not shown) .A drive roller 39a fixed to the support shaft 37a and a support shaft 37b
A pair of transport rollers 39 for transporting the sheet material P fed from the feed roller 33 to the apparatus main body 2 by a driven roller 39b attached to the drive roller 39a and pressed against the drive roller 39a.
Is configured.

A pair of L-shaped support members 40 are rotatably mounted on the support shaft 37a, and a plurality of feed rollers 33 are fixed to each lower end of the support member 40. 41 is rotatably mounted. The support shaft 37a and the support shaft 41 are connected by a belt 42, and when a paper supply command to the vertical paper supply unit 6 is issued, the paper supply roller 33 rotates in the direction of the arrow to select a cassette, for example, a cassette. The sheet material P in 31 is fed in the direction of arrow 51.

At the free end of the horizontal portion of each support member 40, both ends of a lever 43 are attached, respectively.
It is inserted into a long hole 45a drilled at the free end of 45.
The base of the drive member 45 is rotatably supported by a support shaft 46. A plunger 47a of a solenoid 47 is pivotally mounted on the upper end of a short arm rising from the base of the drive member 45. The solenoid 47 operates when the carriage 27 shown in FIG. 1 moves, and moves the paper feed roller 33 from the paper feed position 33A to the retracted position 33B (see FIG. 3) as described later. .

The support member 40, the lever 43, the driving member 45, the solenoid 47, and the like constitute a release unit 36 for moving the paper feed roller 33 to the retracted position.

A cassette lid 52 shown in FIG. 4 is attached to each of the cassettes 29 to 32 shown in FIG.
As shown in FIG. 4, a base of a biasing member 57 made of a leaf spring is fixed to the back side of the cassette lid 52, and two sets of cut-and-raised portions 57a formed at the free end of the biasing member 57 are provided. , 57b
A pressure roller 59 is rotatably mounted on a support shaft 59a. The pressure roller 59 is connected to the cassettes 29 to 32.
The buckling of the sheet material P over time is prevented by pressing the sheet material P stored therein.

An arm member 60 is non-rotatably inserted into the elongated erect 57a among the cut-and-raised erects 57a and 57b, and the arm member 60 is elongated in a long hole 52c formed in both side plates 52a and 52b of the cassette lid 52. Respectively extend through. At both end portions of the arm member 60, arm portions 60a inclined toward the open side of the cassette lid 52 are formed. Urging member 57, pressure roller
A buckling prevention mechanism (buckling prevention means) 53 for preventing buckling of the sheet material P is constituted by 59 and the like.

On both sides below the paper feed roller 33, contact / separation members 62 are rotatably supported by a support shaft 63, and one end of the contact / separation member 62 is locked to a fixed member at the upper end. The other end of the tension spring 65 is locked. The lower end of the contact / separation member 62 is connected to the plunger 66a of the solenoid 66 via a connection member 67. Further, the contact / separation member 62 is formed with an arm 62a facing the carriage 27 side, and an inclined portion 62b capable of engaging with the arm 60a of the arm member 60 is formed at an end of the arm 62a. Is formed.

The solenoid 66 is turned on when the sheet material P is fed.
Then, the inclined portion 62b of the contact / separation member 62 is engaged with the arm portion 60a of the arm member 60 to move the free end of the urging member 57, that is, the pressure roller 59 in the direction of the arrow 61. The solenoid 66, the contact / separation member 62, the arm member 60, and the like constitute a means for releasing the action of the buckling prevention mechanism 53, that is, a contact / separation mechanism 55 for bringing the pressure roller 59 into and out of the sheet material P. . Such a contact / separation mechanism 55 is also provided on the opposite end of the carriage 27 as shown in FIG.

Next, regarding the carriage 27 that moves the fixed table 25, the sixth
This will be described with reference to the drawings.

In the figure, the carriage 27 is partitioned by a plurality of partition plates 27a, and rooms for accommodating the cassettes 29 to 32 are respectively formed. A size detection sensor 70 for detecting the size of the sheet material P stored in the cassette is provided for each room on the side plate 27b on the back side of the carriage 27, and the size detection sensor 70 is arranged in the vertical direction. A plurality of switches 70a are provided.
The size of the sheet material P is detected based on whether 0a is pressed. The side plate 27b is provided with a hole 71 for each room to allow the contact / separation member 62 of the contact / separation mechanism 55 to enter and exit.

6, the cassette 30 is inserted into the carriage 27 from the near side of the carriage 27. A plurality of projections 72 are provided along the longitudinal direction on the back side of the cassette 30. The arrangement of the projections 72 is individually determined according to the size of the sheet material P stored in each of the cassettes 29 to 32. Stipulated.
For example, when the cassette 30 is inserted into the carriage 27, by detecting which switch 70a of the size detection sensor 70 is pressed, it is possible to know which size sheet material P is stored in which room of the carriage 27. It has become.

A plurality of rollers 73 are provided at the bottom of the carriage 27 so as to move on the fixed base 25 smoothly. A rack 75 is formed on the front side surface of the carriage 27, and is connected to a stepping motor (drive source) 77 via an idler 76. The front of the carriage 27 (first
A flag 79 is provided on the left side (in the figure), and when the flag 79 turns on a home position sensor 80 provided on the cabinet 2a, the home position of the carriage 27 is detected. In addition, the above-mentioned roller 73 and rack
The driving means 74 for moving the selected cassette in the carriage 27 to the position of the paper feed roller 33 is constituted by 75 and the like.

A push-up member 81 having an inclined surface 81a is formed on the fixed base 25 below the sheet feeding roller 33, and the inclination angle of the inclined surface 81a is substantially θ. Also,
Each of the partition plates 27a has a notch 27c for avoiding the inclined surface 81a. The cassettes 29 to 32 in the carriage 27 are pushed up by the push-up member 81 when the carriage 27 moves so that the upper end of the sheet material P in the cassettes 29 to 32 moves to the sheet feeding position 33A of the sheet feeding roller 33. Has become. As described above, since each of the cassettes 29 to 32 is inclined at an angle θ with respect to the moving direction of the carriage 27, the direction 82 in which the selected cassette is pushed up by the push-up member 81 and moves (see FIG. 10). Corresponds to the vertical direction of the sheet surface of the sheet material P.

FIG. 7 is a block diagram of the control unit 83 of the sheet feeding unit.

In the figure, a sheet size detection sensor 70 is a detection circuit.
84, the home position sensor 80 via a detection circuit 85, and the paper feed position sensor 50 via a detection circuit 87 to the CPU 89.
, And each signal is inputted.

On the other hand, a signal is transmitted from the CPU 89 to the solenoid 47 for releasing the sheet feeding roller via the drive circuit 90, a signal is transmitted to the solenoid 66 for releasing the buckling prevention mechanism 53 from the drive circuit 91, and the drive circuit 92 A signal is transmitted to a stepping motor 77 for moving the carriage 27 via the carriage 27, and the carriage 27 is driven.

Further, the CPU 89 is also connected to a panel control device 93 of the apparatus main body 2 of the image forming apparatus 1, and receives signals such as a copy key and the number of copies.

Next, the operation of moving the carriage 27 when replacing the cassette at the paper feed position 33A with another cassette will be described with reference to the flowcharts of FIGS.

As shown in FIG. 11A, the required cassettes 29 to 32 are first selected from the panel control device 93 (S1a). As shown in FIGS. 8A to 8C, the carriage 27
Cassettes 29-32 are inserted and B4, A4R, A from the left
Each of the sheet materials P of A3 and A4 is stored, and the cassette size signal is transmitted to the CP by the size detection sensor 70 described above.
Entered in U89. Now, assuming that the cassette is selected from the position of the cassette 29 of B4 to the position of the cassette 30 of A4R, an A4R cassette size signal is input to the CPU 89. Here, the fact that B4 is selected at this time is input and recorded as a signal. In addition, CPU89
Are programmed so that the cassette size signal of the A4R and the position of the cassette 30 can be recognized.

Subsequently, a solenoid 47 for releasing the feed roller (FIG. 2,
(See FIG. 3) is turned on, and the paper feed roller 33 is turned on as shown in FIG.
Is rotated in the direction of the arrow 35 from the sheet feeding position 33A shown in FIG. With the paper feed roller 33 retracted, the stepping motor 77 is then moved to the sixth position.
By starting rotation in the direction of arrow 95a in the figure,
The carriage 27 moves in the direction of arrow 26a as shown in FIG. 8A (S3a).

When the carriage 27 further moves in the direction of the arrow 26a, it is checked whether or not the flag 79 provided at the front of the carriage 27 blocks the home position sensor 80 (see FIG. 6) (S4a). Here, the home position sensor 80
Is interrupted by the flag 79, an ON signal is generated. The carriage 27 has a home position sensor 80
It keeps moving in the direction of arrow 26a until it is turned on. As soon as the home position sensor 80 is turned on, the rotation of the stepping motor 77 is stopped (S5a... State in FIG. 8 (b)).

Subsequently, the stepping motor 77 is indicated by an arrow in FIG.
The carriage 27 is moved in the direction of arrow 26b by reversing the direction of 95b (S6a). Here, a distance (step amount) for moving the selected cassette (here, the cassette containing A4R) 30 to the sheet feeding position is calculated, and it is checked whether or not the carriage 27 has moved to a predetermined position ( S7a). If the carriage 27 has not moved the predetermined distance, S6
After flying to a, the carriage 27 continues to move.
When the carriage 27 has moved a predetermined distance, the rotation of the stepping motor 77 in the direction of the arrow 95b is stopped to stop the carriage 27, and the carriage 27 is brought into the state shown in FIG. 8C (S8a).

Finally, the solenoid 47 (see FIG. 2) for releasing the paper feed roller is turned off, and the paper feed roller 33 rotates from the retreat position 33B to the paper feed position 33A as shown in FIG. It comes into contact with the sheet material P of the selected cassette 30 (S9a). With the above operation, the cassette exchange operation is completed, and the vertical paper feeding unit 6
Is ready for paper feeding.

Next, the sheet feeding operation of the sheet material P will be described. Eleventh
FIG. 2B is a flowchart showing the flow of the operation of the apparatus.

First, the user inputs a desired number of copies from an operation panel (not shown) (S1b), and a start button is pressed (S2b). Next, the solenoid 6 for the buckling prevention contact / separation member 62 is used.
6 (see FIGS. 4 and 5) is turned on (S3b), whereby the contact / separation member 62 is moved from the state of FIG. 5 (a) to the arm 27a as shown in FIG. 5 (b). Respectively. By the rotation of the contact / separation member 62, the arm 62
As shown in FIG. 4, each of the arm portions 60 of the arm member 60
a is pressed to move the pressure roller 59 provided on the arm member 60 and the urging member 57 in the direction of the arrow 61. When the pressure roller 59 moves in the direction of arrow 61, the pressure roller 59
Of the sheet material P in the cassettes 29 to 32 against the sheet surface, that is, the buckling prevention function of the buckling prevention mechanism 53 is released. Thereby, the sheet material P in the cassettes 29 to 32
And the buckling prevention mechanism 53 does not hinder the sheet feeding operation.

Next, a paper feed position sensor that detects the position of the paper feed roller 33
50 signals are examined (S4b). If the paper feed position sensor 5
If the signal of 0 is OFF, it indicates that the sheet feed roller 33 has not yet contacted the sheet surfaces in the cassettes 29 to 32. At that time, a stepping motor (driving A signal is sent to the source 27, and one of the cassettes 29 to 32 selected together with the carriage 27 is moved to the paper feed roller 33 for a predetermined time (S5b).
After that, the stepping motor 77 is stopped, and the signal of the sheet feeding position sensor 50 is checked again. If the signal is not turned on yet, the stepping motor 77 is rotated again to set the cassette.
29-32 are moved.

By the above operation, the paper feed roller 33 is reliably brought into contact with the sheet material P of the selected cassette, and then, as shown in FIG. Form a road. Selected cassette, eg cassette 31
As the sheet material P is sequentially fed, the position of the uppermost surface of the sheet material gradually shifts toward the bottom plate side. By taking the above-described flow, the sheet material P is fed by the sheet feeding. Even if the amount of sheet material decreases, the cassette 31 always moves toward the paper feed roller 33 (in the direction of arrow 82) as shown in FIG. Stable sheet material supply is possible regardless of the storage amount of P.

Further, as shown in FIG. 10, the above-described push-up member 81 is provided on the fixed base 25. As described above, as the sheet material P in the selected cassette 31 decreases, the carriage 27 (see FIG. 8) moves in the direction of the arrow 26a. At this time, the cassette 31 in the carriage 27 moves up the push-up member 81. Move in the direction of arrow 82 in the figure along the inclined surface 81a, and are gradually pushed up obliquely upward. Since the upward movement of the cassette 31 in the oblique direction is in the same direction as the right angle direction of the sheet material P, the sheet material P in the cassette 31 is always kept at a predetermined position from the front end of the sheet material irrespective of the increase or decrease in the number of stored sheets. The sheet feeding roller 33 can be brought into contact at a position separated by the distance δ, and a stable sheet feeding operation of the sheet material P is guaranteed.

Based on the operation flow as described above,
When the roller 33 is placed at a position where it comes into contact with the uppermost surface of the sheet material P in the cassette 31 and forms a regular conveyance path, a signal is supplied to a drive source (not shown) to support the spindle 37a (second shaft). Is rotated, and the sheet feeding roller 33 rotates in conjunction with the support shaft 37a to feed the sheet material P. The fed sheet material P is sent to the image forming unit 5 by the transport roller pair 39 and the transport roller pair 23 (see FIG. 1) to form an image (S6b, S7b).

After recognizing that the number of copies (image formation) has been made by the user, the paper feed roller 33 stops its rotation. Next, a buckling prevention solenoid 66 shown in FIG.
As a result, the pressure roller 59 of the buckling prevention mechanism 53 comes into contact with the sheet material P in the cassette 31 again to prevent buckling due to the temporal change of the sheet material P (S9b). If the number of copies has not yet reached the number specified by the user, the process returns to S4b again, and image formation is repeated until the number of copies reaches the predetermined number.

(G) Effects of the Invention As described above, according to the present invention, the following effects can be obtained.

(1) When moving a carriage containing a multi-stage vertical cassette arranged in a substantially vertical direction in the horizontal direction for cassette selection, the selected cassette is pushed up to the sheet feeding means by the inclined surface of the push-up member. Being moved
Eliminates the need for a mechanism to raise the cassette to the paper feeding position after the horizontal movement required by the conventional device, shortening the cassette selection time and increasing the number of sheets used for vertical cassette paper feeding. , Mass storage is possible.
Selection of a predetermined cassette can be performed only by moving the carriage in the horizontal direction.

(2) The cassette is provided with buckling prevention means for preventing buckling of the sheet material in the upright position, and presses the sheet material stored in the cassette. Even if the sheet is stored in the cassette for a long time in this state, it is possible to prevent buckling of the sheet material and defective feeding due to the buckling.
Further, the buckling prevention means cancels the buckling prevention action by the contact / separation means at the time of feeding the selected cassette, so that the load on the sheet material at the time of paper feeding is eliminated, and double feeding or the like is performed. The sheet material can be fed stably without causing paper jam.

(3) The means for moving the sheet surface of the selected cassette up to the sheet feeding position is also used as the driving means for the cassette in the horizontal direction at the time of selecting the cassette, so that the sheet feeding position required in the conventional apparatus is used. A mechanism for moving the cassette upward and a middle plate for constantly pressing the sheet material against the sheet feeding means, a compression spring, and the like become unnecessary, thereby reducing the space of the cassette itself and the space for moving the cassette, miniaturizing the apparatus, and further reducing the size of the cassette. The selection time can be reduced, and a large number of sheet materials can be stored.

[Brief description of the drawings]

FIG. 1 is a vertical sectional front view of an image forming apparatus to which an embodiment of the present invention is applied, FIG. 2 is a perspective view showing a sheet feeding means and a release mechanism thereof, FIG. FIG. 5 is a perspective view of a buckling prevention mechanism provided on the cassette lid and a contact / separation mechanism thereof, FIG. 5 is a front view showing the same operation, FIG. 6 is a perspective view of the carriage unit, and FIG. 8, FIG. 8 is an operation diagram of the cassette selection, FIG. 9 is a side view of the sheet feeding unit, FIG. 10 is a side view showing the operation of moving the cassette upward, and FIG. FIG. 12 is a flow chart showing the operation of the apparatus, FIG. 12 is a vertical sectional side view of a plurality of image forming apparatuses to which a conventional paper feeding unit is applied, and FIG. 13 is a longitudinal section of an image forming apparatus to which a conventional vertical cassette is applied. FIG. 14 is a vertical sectional side view of a main part of the cassette and a sheet feeding unit. P: sheet material, 1: image forming apparatus, 2: apparatus main body, 2a: cabinet, 5: photosensitive drum (image forming means), 6: vertical paper feeding unit, 27: carriage, 29 32 to vertical cassette, 33 paper feed roller (paper feed means), 33A paper feed position, 33B retreat position, 36 release mechanism for paper feed means, 47 release mechanism 50 solenoids
... Paper feed position sensor, 52 ... Cassette lid, 53 ... Buckling prevention mechanism (buckling prevention means), 55 ... Contact / separation mechanism, 57 ... Biasing member, 60 ... Arm member, 66 ... Seat Solenoid for anti-buckling means, 70
... Size detection sensor 74... Driving means 77. Stepping motor (drive source) 80... Home position sensor 81.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-134444 (JP, A) JP-A 52-36930 (JP, U) JP-A-58-55954 (JP, U)

Claims (3)

(57) [Claims] A plurality of cassettes for accommodating a sheet material; and supporting the cassettes in a standing state inclined at a predetermined angle;
A carriage capable of moving back and forth in a horizontal direction on a fixed base; a driving unit for driving the carriage; and an inclined surface provided on the fixed base side for selectively pushing up the carriage in accordance with the movement of the carriage. An image forming apparatus, comprising: a push-up member having the sheet feeding means for feeding a sheet material from a cassette pushed up by the inclined surface to an image forming unit. 2. A plurality of buckling prevention means for pressing and holding a sheet material surface in order to prevent the buckling of the sheet material caused by the sheet material stored in each cassette being in an upright state. 2. The image forming apparatus according to claim 1, further comprising: a contact / separation mechanism that releases the buckling prevention unit of the selected and pushed-up cassette from pressing the sheet material when feeding the sheet from the cassette. 3. apparatus. 3. The plurality of cassettes are inclined at an appropriate angle θ with respect to a direction perpendicular to the direction of movement by the driving means, and the sheet surface of the selected cassette is adjusted by the sheet feeding means. 2. The image forming apparatus according to claim 1, wherein an inclination angle of the inclined surface to be moved to the sheet feeding position from a horizontal plane substantially coincides with a vertical direction of the sheet surface of the sheet material.