JPH078497Y2 - Image forming device - Google Patents

Description

TECHNICAL FIELD OF THE INVENTION The present invention relates to an image forming apparatus such as an electrophotographic copying machine and a paper feed cassette used for the same. More specifically, the present invention relates to a case of storing a large size and large capacity sheet. The present invention also relates to an image forming apparatus equipped with a paper feed cassette that is excellent in operability and that allows paper to be easily replenished or replaced.

[Prior art and its problems]

Paper feeding methods capable of stacking and storing a large amount of paper in a predetermined portion to enable continuous automatic paper feeding are roughly classified into a cassette method and a fixed tray method.

In the cassette method, paper is stored in separate housings (cassettes) for each size, and when exchanging or replenishing paper, the cassette is pulled out from the main body of the image forming apparatus and placed on a nearby table or the like. When changing the size, the method is to replace each cassette.

On the other hand, the fixed tray system is a system in which a tray for stacking paper sheets is fixedly installed in the apparatus main body and the paper sheets are directly replenished to the tray.

In the latter fixed tray method, it is troublesome to store the previous sheet when switching the sheet size, and since there is usually no cover, the stacked sheets are distorted in a high humidity environment.

On the other hand, the former cassette system is excellent in operability at the time of paper exchange and paper storability, but has the following problems. It is a large size storage paper such as A3 250
In the case of a large cassette that can store a large amount of paper up to 500 sheets, the weight is considerable, and the operability when attaching and detaching the cassette is extremely poor.

[Purpose of device]

The present invention has been made in view of the above-mentioned problems of the prior art. Even in the case of a large cassette that stores a large amount of large-sized paper, the operability can be easily attached and detached and the paper can be easily replenished or replaced. It is an object of the present invention to provide an image forming apparatus provided with a paper feed cassette excellent in performance.

[Key points of device]

According to the present invention, the above object has a top surface portion and a side surface portion,
An apparatus main body having an image forming unit therein, a paper storage cassette that can be inserted into and removed from a mounting opening formed in the side surface of the apparatus main body, and the above-mentioned apparatus installed inside the apparatus main body and mounted in the mounting opening. In an image forming apparatus including a sheet feeding unit that comes into contact with the uppermost sheet of the sheets stacked in the sheet storing cassette and feeds the sheets one by one to the image forming unit, the sheet storing cassette is attached to the mounting opening. An upper plate portion having an opening that allows the feeding means and the topmost sheet to come into contact with each other when mounted,
A cassette housing formed so as to open substantially the entire lower surface side facing the upper plate portion, and the cassette movably between an open position for opening the lower surface side for loading paper and a closed position for closing the lower surface side. Each of the apparatus main body and the cassette housing includes a bottom plate supported by a housing and having a paper stacking surface for stacking paper when in the closed position, and holding means for holding the bottom plate in the closed position. To rotatably support the sheet storage cassette at a first position for releasably engaging with each other and for mounting the sheet storage cassette in the mounting opening and at a second position for reversing the upper plate portion downward. Engaging means that cooperate with each other to form a rotation fulcrum is provided, and the opening of the paper storage cassette rotated to the second position is mounted on the upper surface of the apparatus body toward the side surface. A loading section is provided to place the paper storage cassette on the loading section. In this state, the bottom plate is opened to load a sheet, and the bottom plate is rotated to the closed position with the engaging means as a fulcrum to insert and remove the sheet storage cassette into and from the mounting opening. This is achieved by providing an image forming apparatus characterized by the above.

[Example of device]

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 and 2 are schematic cross-sectional views showing a schematic structure of an optical writing printer as an embodiment of an image forming apparatus of the present invention and an operation procedure of a paper feed cassette according to the present invention.
Further, FIG. 3 is a perspective view showing the paper feed cassette, and FIG. 4 is a perspective view showing the appearance of the optical writing printer with the paper feed cassette removed.

In FIG. 1, a photosensitive drum 2 is rotatably supported at a substantially central portion of a printer body 1, and is driven and rotated in a direction of an arrow. Around the photosensitive drum 2, along the rotation direction thereof, a uniform charging device 3, an optical writing head 4, a developing device 5,
The transfer charger 6, the cleaner 7, etc. are sequentially arranged to form an electrophotographic image forming process.

A paper feed unit is formed at the bottom of the printer body 1 and the first paper feed cassette 8 is inserted therein. First paper feed cassette 8
Is a normal size cassette that stores commonly used A4 and B5 size sheets, for example, and is configured to be freely inserted and removed in the horizontal direction. A first paper feed roller 9 is arranged on the back side (right side in the drawing) of the paper feed unit. The first paper feed roller 9 is formed in a substantially half-moon shape, and when rotated, its circumferential surface comes into contact with the upper surface of the stacked paper sheets and pushes down against the push-up spring 8a to feed the uppermost paper sheet. At the front (back side) of the first paper feed cassette 8, the sheet is transferred to the transfer section at the same timing as the turn guide 10 for reversing the paper feeding direction 180 and the movement of the image on the photosensitive drum 2 to the transfer section. A sheet carry-in path including a pair of standby rolls 11 for sending out is formed.

On the side opposite to the transfer side with respect to the transfer section, the conveyance guide plate 12,
A sheet unloading path including a heat roll fixing device 13 and a pair of discharge rollers 14 is formed, and after the toner image is transferred, it is heat-fixed and discharged along the unloading path. Output stacker part 15 used as
Discharged on top. In the optical writing printer 1 of this example, the insertion port side (left side in the figure) of the first paper feed cassette 8 is the front of the machine body, and the operation panel 16 and the like are installed on the side plates.

Then, on the back side of the printer 1, a second paper feed unit is formed, and the second paper feed cassette 17 is at the rear end (with respect to the paper feed direction).
Is installed in a posture in which it is lifted diagonally upward. The second paper feed cassette 17 is, for example, 250 to 5 large sheets of A3 size paper.
It is a large paper cassette that can store about 00 sheets. The second paper feed cassette 17 is provided with a pair of hooks 17a (see FIG. 3) standing upright on both sides slightly forward of the center of the upper surface. The pair of hooks 17a are attached to the printer 1 main body as shown in FIG. The printer main body 1 is rotatably supported by rotatably engaging a pair of bearing shafts 1a, 1a recessed on the back side of the upper part. A second sheet feeding roller 18 having the same half-moon shape as the first sheet feeding roller 9 is arranged in the second sheet feeding section to which the tip of the second sheet feeding cassette 17 is attached. Roll 18
A paper feed guide 18a is laid between the pair of standby rolls 11 described above and a second paper feed path is formed. Therefore, the second paper feed roller 18 starts rotating and the paper delivered from the second paper feed cassette 17 is guided to the standby roll pair 11 along the paper feed guide 18.

Here, the configuration of the second paper feed cassette 17 will be described with reference to FIG. FIG. 3 shows a state in which the second paper feed cassette 17 is turned upside down and the bottom plate 19 is opened. In this state, replenishment or replacement of paper is performed. The bottom plate 19 has one end rotatably supported by a corresponding end of the housing 20 via a shaft (not shown). A push-up plate 21 is rotatably supported on the inner surface of the bottom plate 19. As shown in FIG. 2, the push-up plate 21 is rotatable by inserting a shaft 21a provided at one end thereof into a bearing portion 19a formed substantially in the center of the inner surface of the bottom plate 19. The pair of compression springs 22 and 22 are supported and the other end portion is connected to the inner surface of the bottom plate 19 and are coupled to the bottom plate 19.
A friction member 21b is planted at the end of the push-up plate 21 on the side opposite to the shaft support, so that the final sheet (bottom sheet) can be accurately fed one by one. A locking portion 19b is formed at the center of the end of the bottom plate 19 on the side opposite to the shaft support.
The bottom plate 19 can be held in the closed state by engaging with the locking port 20b formed in the rear wall 20a of the 20.

A pair of protrusions 20c, 20c are formed on the inner surface of the rear wall 20a of the housing 20, and the rear end surfaces of the storage sheets are brought into contact with these to prevent them from directly contacting the rear wall 20a. The bottom plate locking portion 19b can always be reliably engaged with the locking port 20b.
A paper feed port 20d is formed at the front end of the housing 20, and the stored paper is delivered from this. A pair of separation claws 23, 23 is provided at both corners of the front end of the paper feed port 20d so as to be vertically movable. The separation claws 23 are provided to lock both edges of the sheet to be delivered and separate the sheet to prevent double feeding.

Next, an operation procedure of the second paper feed cassette 17 will be described.

When replenishing the second paper cassette 17 with paper, first the first
The second sheet feeding cassette 17 at the sheet feeding position shown in the figure is rotated counterclockwise by about 120 ° and set to the sheet replenishing position placed on the upper surface of the printer body 1 shown in FIG.
In this case, the operator can easily rotate the second paper feed cassette 17 by extending the hand without moving the whereabouts from the front side to the back side of the printer. Also, the second paper feed cassette 17
Although a large amount of large-sized paper can be stored and the weight tends to be large, even in such a case, it can be easily attached to and detached from the printer body 1 only by a rotating operation, and the operability is extremely excellent.

When the second paper feed cassette 17 is set to the above-mentioned paper replenishment position, the engaging portion 19b of the upper bottom plate 19 and the engaging opening 20b are disengaged, and the bottom plate 19 is shown in FIG. As shown in the figure, the housing 20 is opened by rotating it clockwise. In this state, new paper may be replenished, but when the front and back of the paper are set, the paper is turned upside down and loaded in the housing 20. At this time, even if the already stored paper remains, new paper will be replenished to the lower side (during paper feeding), and the remaining paper can be consumed normally and old paper can be stored for a long time in the cassette. The inconvenience of being left inside and being contaminated is naturally prevented.

When the replenishment of the sheets is completed, the bottom plate 19 can be positively engaged with the housing locking port 20b by simply rotating the bottom plate 19 in the counterclockwise direction and closing it by utilizing the elasticity of the bottom plate locking portion 19b itself. . After closing the bottom plate 19, the entire second paper feed cassette 17 is rotated clockwise to return to the paper feed position shown in FIG. This completes the preparation for feeding from the second sheet feeding unit. After this, the operator confirms that the paper feed section selection display on the operation panel 16 is the second paper feed section, and then the print start key 16
When a (see FIG. 4) is pressed, the second paper feed roller 18 starts to rotate, and, for example, A3 sheets are separated one by one and fed toward the above-mentioned transfer section. The A3 sheet on which the image has been transferred and fixed is discharged onto the discharge tray unit 15 set on the upper surface of the printer body 1 as the discharge roller 14 rotates. A3 discharged
The paper is placed along the upper surface of the main body, but since the paper is large in size, the front end of the paper sticks out from the upper surface of the main body. However, in the printer 1 of this example, since the upper surface of the second sheet feeding cassette 17 extends obliquely upward at that position, the sheet is ejected.
The front edge of A3 paper is smoothly placed on the upper surface and placed. That is, the upper surface of the second paper feed cassette 17 also has an effect as a paper discharge tray, and even a large size paper can be stably formed with a good stack without dropping.

When changing the size of the paper to be fed from the second paper feed unit, the second paper feed cassette 17 may be replaced. In this case, the engagement between the hook 17a and the support shaft 1a can be easily released. Can be easily replaced by operation.

As described above, in the optical writing printer 1 of this example, since the second paper feeding unit is provided on the back surface of the printer, the outer shape is smaller than that in the case where two stages are provided in parallel to the lower portion of the normal printer, and the installation space is also omitted. it can.

In the above embodiment, the "rotary paper feed cassette" according to the present invention is applied as the second paper feed cassette in a printer having two paper feed units, but the present invention is not limited to this. It can also be applied to a normal image forming apparatus having a single sheet feeding unit. Besides, the present invention should not be limited to the preferred embodiments described above, and it is needless to say that various modifications can be made within the technical scope of the present invention.

[Effect of device]

As described above in detail, according to the present invention, by rotating the paper feed cassette to attach / detach it, it is possible to easily attach / detach even a heavy-duty cassette storing a large amount of large-size paper and replenish paper. It can be easily replaced. or,
When the present invention is applied as an optional second sheet feeding cassette, a so-called "option sheet feeding apparatus", which tends to be large in size and complicated in structure, can be easily realized in a small size.

[Brief description of drawings]

1 and 2 are schematic cross-sectional views showing the sheet feeding position and sheet replenishing position of a rotary sheet feeding cassette in an optical writing printer as an embodiment of the present invention, and FIG. FIG. 4 is a perspective view showing the paper cassette, and FIG. 4 is a perspective view showing the appearance of the optical writing printer from which the rotary paper feeding cassette is removed. 1 ... Printer body, 1a ... Bearing shaft, 8 ... First paper feed cassette, 9 ... First paper feed roller, 17 ... Second paper feed cassette, 17a ... Hook, 18 ... Second paper feed Paper roller, 19 …… bottom plate, 20 …… case, 21 …… push plate, 22 …… compression spring, 23
...... Separating claw.

Claims (1)

[Scope of utility model registration request] 1. A device main body having an upper surface portion and a side surface portion and an image forming portion inside, a paper storage cassette that can be inserted into and removed from a mounting opening formed in the side surface portion of the device main body, An image provided with a feeding unit that is provided inside the apparatus main body and abuts the topmost sheet of the sheets stacked in the sheet storage cassette that is loaded in the loading port and feeds the sheet one by one to the image forming unit In the forming apparatus, the paper storage cassette faces an upper plate portion having an opening that allows the feeding means and the uppermost paper to come into contact with each other when the cassette is mounted in the mounting opening. A cassette housing formed to open substantially the entire lower surface side, and movably supported by the cassette housing between an open position for opening the lower surface side for loading paper and a closed position for closing the lower surface side. A bottom plate having a paper stacking surface for stacking paper when in the closed position ,
Holding means for holding the bottom plate in a closed position, and a first position for releasably engaging each of the apparatus body and the cassette housing to mount the paper storage cassette in the mounting opening; Engaging means that cooperate with each other to configure a fulcrum of rotation so as to be rotatably supported at a second position in which the upper plate portion is turned down and in an inverted state are provided. A mounting portion is provided for mounting the opening of the paper storage cassette rotated to the second position toward the side surface portion side, and the bottom plate with the paper storage cassette mounted on the mounting portion. Is opened to load the paper, and the bottom plate is closed to rotate to the insertion port of the paper storage cassette by rotating the bottom plate with the engaging means as a fulcrum. Image forming apparatus.