JPH01176731A - Image formation apparatus - Google Patents

Abstract

PURPOSE:To install a large-capacity paper feed cassette in a simple constitution by raising a paper push-up plate while spring force is gradually reduced by a driving motor when the height of paper in the large-capacity cassette becomes lower. CONSTITUTION:In an installed large-capacity paper cassette 7, paper P on a paper push-up plate 302 urged upward by a spring 303 stronger then the loading weight of the paper P is taken out in the same manner as paper in a standard cassette 6 by a take-out roller 45 of an arm 44 mounted in such a manner as to oscillate up and down. When the height of paper is decreased to a designated height, a driving motor 309 is driven to gradually raise the paper push-up plate 302 through reduction mechanisms 308, 307, 305 and a link lever 304 while spring force is reduced. Thus, the large-capacity paper feed cassette can be installed in a simple constitution, and the capacity of a paper feed cassette driving system can be reduced.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention relates to an image forming apparatus such as an electronic copying machine,
In particular, the present invention relates to an image forming apparatus that has an improved function of feeding paper into the main body of the apparatus.

(Prior Art) Normally, in an RPC copying machine, a device is used to feed paper into the main body of the device, which has built-in image forming process components such as charging, development, transfer, cleaning, and fixing, depending on the size of the paper. At the same time, paper feed cassettes are installed in multiple stages (upper and lower) in each loading section of the main body of the apparatus, and sheets of frequently used sizes are separately accommodated in the large capacity paper feeder, and this large capacity paper feeder is Some are attached to the main body of the device.

(Problems to be Solved by the Invention) Conventionally, in particular, when a large-capacity paper feeder is attached to the main body of the apparatus, the large-capacity paper feeder itself has become large and can be installed in a wide area. Not only does it take up space, but the mechanism itself for pushing up and feeding large volumes of paper is complicated.
There are problems in that the capacity of the drive motor must be increased, which inevitably increases the cost and power consumption.

The present invention has been made under the above circumstances, and its purpose is to reduce the capacity of the drive system of the paper feed cassette that pushes up paper with a simple 1w1 configuration, and to reduce power consumption. An object of the present invention is to provide a small and inexpensive image forming apparatus that can achieve the following.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention provides an apparatus incorporating image forming process configuration means such as charging, development, transfer, cleaning, and fixing. The main body is provided with a paper feeding means consisting of a standard cassette that accommodates a normal amount of paper and a large capacity cassette that accommodates a large capacity of paper, and the paper in the standard cassette and the large capacity cassette is loaded into each of the paper cassettes. The image forming apparatus is configured to take out sheets one by one by a paper take-out means including a take-out roller provided in a section, and the large-capacity cassette has a standard height of the paper stored in the large-capacity cassette. It has a built-in paper push-up means that operates to push up the paper when the height becomes lower than the normal amount of paper stored in the cassette, and this paper push-up means drives the paper stored in the large-capacity cassette. A paper push-up plate that is pushed up via a push-up drive means by a motor, and a spring that always biases and supports the paper push-up plate upward, and the spring is housed in the large-capacity cassette. It has a spring force slightly stronger than the maximum weight of the paper, and is configured to raise the paper pushing plate while gradually loosening this spring force by driving the drive motor.

(Function) That is, one aspect of the present invention is to push up the paper stored in the paper feed cassette attached to the attachment portion of the apparatus main body by the paper push-up plate via the push-up drive means by the drive motor, This paper push-up plate is supported by being constantly biased upward by the biasing force of a spring that has a spring force slightly stronger than the maximum weight of paper stored in the cassette, and this spring force is used to drive the drive motor. Since the paper push-up plate is raised while being gradually loosened, the pushing up of the paper can be assisted by the biasing force of the spring, and the capacity of the drive motor can be reduced, reducing consumption. It becomes possible to reduce power consumption.

(Embodiment) The present invention will be described in detail below with reference to an illustrated embodiment.

FIG. 1 shows the overall appearance of an electronic copying machine as an image forming apparatus according to the present invention, and FIG. 2 shows its internal structure, with numeral 1 indicating the main body of the apparatus. Inside this device body 1,
Image forming process configuration means 2 such as charging, developing, transferring, cleaning, and fixing are built-in.

On the upper side thereof, an automatic document supply/ejection unit device 4, which will be described later, is provided for setting a document on the document placement glass 3 and ejecting the document on the document placement glass 3. Furthermore, an operation panel 5 is provided on the front edge of the top surface.
is located.

On the right side of the apparatus main body 1, there are a first paper feed cassette (hereinafter referred to as a standard cassette) 6 containing paper P such as plain paper to be supplied to the image forming process configuration means 2; Two paper feed cassettes (hereinafter referred to as large-capacity cassettes) 7 are removably inserted into two upper and lower stages, respectively, and a paper feed means 8 is installed, and constitutes this paper feed means 8. The paper storage height H2 of the lower large-capacity cassette 7 is higher than the paper storage height H□ of the upper standard cassette 6 (r(z<r”tz); A paper feed tray 9 for collecting fixed sheets P is installed.

The apparatus main body 1 is composed of an upper unit 1a and a lower unit 1b, and as shown in FIG. A paper feed means 8 and a paper feed tray 9 each consisting of a large-capacity cassette 6 and a large-capacity cassette 7 are installed.

Further, in the image forming process configuration means 2, a drum-shaped photoreceptor 20 as an image carrier is arranged approximately in the center of the upper unit la, and a drum-shaped photoreceptor 20 is arranged around the photoreceptor 20 along its rotation direction. Charging device 21, erasing device 22. An exposure section 23a as an exposure device 23, a developing device 24. Transfer device 25. Stripping device 26, cleaning device 27, and static eliminator 28
etc. are arranged in order, while paper P is automatically fed from the paper feed means 8 along the inner bottom of the upper unit 1a, or a manual paper feed tray 3o which also serves as a cover for the standard cassette 6. The manually fed paper P is transferred to the image transfer section 3 between the photoreceptor 2o and the transfer device 25.
1 and a pair of paper ejection rollers 3 provided on the left side of the apparatus main body 1.
A paper transport path 33 leading to the paper discharge tray 9 via the paper transport path 3 is formed, and the image transfer section 3 of this paper transport path
An aligning roller pair 34 is arranged upstream of the roller 1, and a fixing device 35 is arranged downstream thereof.

On the other hand, in the vicinity of the mounting portion of the standard cassette 6 constituting the paper feeding means 8, there is a first take-out roller 41 attached to a swingable first arm 40 and for taking out sheets P one by one. A first conveying roller 42a and a first conveying roller 42a receive the sheet P taken out through the take-out roller 41 and send it into a first branch conveying path 33a forming the upstream side of the sheet conveying path 33. A first paper separation and conveyance means 42 consisting of a separation roller 42b is provided, and the paper P manually fed from the manual paper feed tray 30, which also serves as the cover of the standard cassette 6, is separated from each other. A manual feed roller 43 is provided that feeds the paper into the first branched conveyance path 33a through between the first conveyance roller 42a and the first separation roller 42b.

Also, in the vicinity of the mounted portion of the large-capacity cassette 7, there is a second take-out roller 45 that is attached to a swingable second arm 44 and takes out sheets P one by one, and a second branch conveyance path 3 that receives the taken out paper P and forms the upstream side of the paper conveyance path 33;
3b, the second conveying roller 46a and the first
A second paper separation and conveyance means 46 is provided, which includes a separation roller 46b, and a paper-out detection switch 5 is installed at the mounting portion of each of the standard cassettes 6 and large-capacity cassettes 7.
0, and a paper size detection switch 51 which also serves to detect the presence or absence of a cassette.

Further, in the figure, 52 is a paper sensor, and this paper sensor 52 is connected to the first and second branch conveyance paths 33a.

33b, that is, near the upstream side of the pair of aligning rollers 34, and the standard cassette 6 or large-capacity cassette 7 is transported via the first or second paper separation and transport means 42, 46. It is designed to be able to detect sheets of paper [).

Further, the exposure device 23 has an exposure lamp 61 surrounded by a reflector 60 that illuminates the back of the document set on the document placement glass 3 provided on the top surface of the device main body 1.
The reflected light from the document surface is reflected by the first mirror 62.
, the second mirror 63 and the third mirror 64 in order to the lens 65, and then the light transmitted through the lens 65 is guided to the fourth mirror 66, the fifth mirror 67, and the sixth mirror 68.
The photoreceptor is guided to the photoreceptor 20 through the following sequentially.

Then, the exposure lamp 6 surrounded by the reflector 60
1 and the first mirror 62 are mounted on a first carriage 69 that is reciprocally movable along the lower surface of the document placement glass 3, and the second mirror 63 and the third mirror 64 are The first and second carriages 69.7o are each mounted on a second carriage 70 that moves in the same direction at half the speed of the carriage 69, and in the state shown in FIG. By moving it in the right direction, the document sheet set on the document placing glass 3 is scanned, and an image corresponding to the document sheet is slit-exposed onto the photoreceptor 20.

Note that the first carriage 69 is equipped with a spotting unit 71 for specifying an area where there is a document stain when copying is desired with the area erased.

The developing device 24 is composed of an upper developing unit 75 for color development and a lower developing unit 76 for black development, each of which is a magnetic brush type equipped with developing rollers 77 and 78. By selectively bringing the .78 close to each other and rotating them, it is possible to selectively develop black or other colors, such as red.

Further, the cleaning device 27 includes a cleaning blade 8
0 is brought into contact with the photoconductor 20 to scrape off the developer (toner) remaining on the photoconductor 20, and the scraped developer is sent out of the casing 82 via an auger 81. It is configured to be discharged and collected in a collection box (not shown).

The fixing device [135] has a heating roller 86 with a built-in heater lamp 85, and a pressure roller 87 that is always urged to be in pressure contact with the heating roller 86, and these are connected by upper and lower casings 88, 89. It has a surrounding structure, and the pair of paper ejection rollers 32 and the paper ejection switch 90 are integrated near the downstream side thereof.

Further, the charging device 21. Transfer device 25 and peeling device 2
6 is each composed of a corona discharge device,
The charging device 21 irradiates the photoconductor 20 with light from a static elimination lamp 95 via a green filter 96, and the erasing device 22 has a large number of LEDs arranged along the longitudinal direction of the photoconductor 20, and It is possible to erase charges in a portion corresponding to a region specified by the unit 71.

Note that in the upper part of the fixing device 35 in the apparatus main body 1,
A cooling fan 55 and a sub-main motor 56 are disposed, and a conveyance belt 57 forming a part of the paper conveyance path 33 is disposed between the peeling device 26 and the fixing device 35. High voltage transformers 58 are arranged below the belt 57, that is, at the bottom of the upper unit 1a. In the drawing, reference numeral 59 denotes a document stacking table on which a document tray in the automatic document supply/discharge unit device 4, which will be described later, is stacked.

That is, the automatic document supply/discharge unit device 4
A separation unit 100 that constitutes a separation means for feeding, separating, and conveying the original documents stacked on the K document stacking table 59, and a conveyance unit 200 that constitutes an original conveyance means arranged adjacent to this separation unit 100. The separation unit 100 is configured to stack originals to be transported on the original stacking table 59 and separate and invert the originals, while the transport unit 200 has one separation unit 10.
0 is conveyed to the exposure position on the document placement glass 3 of the main body 1 of the apparatus, and the document after copying is discharged and stacked on the document ejection table 201. The separation unit 100 and the transport unit 200 are independent from each other, and
The transport unit 200 can be opened and closed to facilitate the removal of document jams and the copying of thick documents such as books. Moreover, the separation unit 100 is.

It is attached on the device main body 1.

As shown in detail in FIG. 3, the separation unit 100 constituting the above-mentioned automatic document supply/discharge unit device 4 has a base 101 attached to the device main body 1 to which the document loading table 59 is attached at one end. A pickup roller 103 is fixed via a bracket 102 and is a take-out roller on the downstream side of the document loading table 59 on the base 101.
A separation roller 104 and a paper feed roller 105 paired with the separation roller 104 are provided in this order, and the pickup roller 103 takes out the uppermost document stacked on the document stacking table 59 one by one, and separates and feeds the document. Paper roller pair 10
A first pair of aligning rollers 106 is provided downstream of the pair of separating/feeding rollers 104 and 105, and the pair of separating rollers 1
The document separated in step 04 is further conveyed to the downstream side.

A second aligning roller pair 107 is provided downstream of the first aligning roller pair 106, and this second aligning roller pair 107 is connected to the first aligning roller pair 106. A document conveyed from the pair 106 or a document conveyed from a reversing path mechanism to be described later is conveyed to the conveying unit 200 side, and a single reversing sheet path mechanism 110 is provided at the upper position thereof.

This reversing paper path mechanism 110 is connected to a transport unit 2 which will be described later.
Three outer paper guides 111°, 112, and 113 and two inner paper guides form a curved paper path path for guiding and reversing the original that has been reversely conveyed from the 00 paper bus mechanism.
It is composed of two paper guides 114 and 115, and three pairs of transport rollers 116 to 118 provided on a curved paper bus path formed by each of these paper guides 111 to 115. ~11
5 is divided into parts to improve jam handling and ease of assembly, and each of the three pairs of conveying rollers 116
118 are arranged so that the conveyance performance of the curved paper path is ensured.

Further, a gate 120 is provided on the downstream side of the second aligning roller pair 107 described above, and this gate 120 is used during paper conveyance from the separation unit 100 to the conveyance unit 200 side, which will be described later, and during document reversal. The paper conveyance from the conveyance unit 200 to the separation unit 100 can be switched and guided.

Further, in the figure, reference numeral 121 denotes a document detecting means 122 provided in the same phase as the pickup roller 103 to detect whether or not a document is stacked on the document stacking table 59 and to control the operation of the separation unit 100. 123 and 124 are document detection sensors installed on the conveyance path between the pair of separating/feeding rollers 104 and 105, which separate and feed the documents one by one, and the first pair of aligning rollers 106; The first and second aligning rollers are spaced apart from each other on the conveyance path between the pair of aligning rollers 106 and 107.
This first jam detection means 1 is a jam detection means.
23 is designed to detect jams, document width, document length, etc. of the document conveyed from the pair of separating/feeding rollers 104 and 105 and the first pair of aligning rollers 106; The second jam detecting means 124 is configured to detect a jam in the document conveyed from the first pair of aligning rollers 106 and a jam in the document conveyed from the reversing paper path mechanism 110. In the figure, reference numeral 125 denotes a third jam detecting means installed on the curved paper path path of the reversing paper path mechanism 110, and is designed to detect a jam in the original to be reversed.

As shown in detail in FIG. 4, the transport unit 200 includes a paper path mechanism 210.
0 transports the original transported from the separation unit 100 to the exposure position on the original placing glass 3 of the apparatus main body 1, and transfers the original after copying to the original output table 201.
A conveyance belt 211 that conveys the paper to the side or reversely conveys it to the reversing paper path mechanism 110 of the separation unit 100, and first and second belt rollers 212 and 213 that drive this conveyance belt 211 by a drive system (not shown). Four sets of presser rollers 214 to 21 for ensuring that the conveyor belt 211 contacts the g document device glass 3 of the device main body 1
7, and a paper guide 2 forming an ejection path so as to guide the original after copying to the original ejection table 201 side.
18, and a discharge roller 219 that conveys the documents on the discharge path by the paper guide 218 to the document discharge table 201 and discharges and accumulates them.

In addition, 220 in the figure shows the document conveyed by the conveyor belt 211 on the document placing glass 3 of the predetermined copying machine unit 1.
This is a document stopper for stopping the document at the upper exposure start position.

Next, the operation of the above-mentioned automatic document supply/discharge unit will be explained. First, when copying a single-sided document.

When a document is set on the document stacking table 59 of the separation unit 100, this "document present" state is detected by the document detecting means 1.
21. In this state, when the copy button on the operation panel 6 of the copying apparatus main body 1 is pressed, the pickup roller 1 inside the separation unit 100 lowers while rotating.
03 picks up the document stacked on the document stacking table 59, and transfers it to separation/feed rollers 104 and 105.
With the rotation of these roller pairs 104 and 105.

For example, a document in a two-sheet state is separated one by one and sent to the downstream side. When the leading edge of the document is detected by the document detection sensor 122 installed in front of the first aligning roller pair 106, after a certain period of time, the first and second aligning roller pairs 106, 107 starts rotating and sends the original to the transport unit 200 side. At this time, the conveyor belt 211 of the conveyor unit 200 is driven in synchronization with the first and second aligning roller pairs 106 and 107, and the document sent from the separation unit 100 is transferred to the conveyor belt 211. The document is conveyed onto the original platen glass 3 of the apparatus main body 1 by the drive of the apparatus main body 1, and the original is stopped at a predetermined exposure start position on the original platen glass 3 of the apparatus main body 1 by the original stopper 220. In this state, the apparatus main body 1 operates and starts copying the original. Then, the end of such a copying process is determined by a signal from the apparatus main body 1, and when the copying operation is completed, the above-mentioned conveyor belt 211 is driven again.
The document in a stationary state on the document placement glass 3 of the apparatus main body 1 is discharged and accumulated on the document discharge table 201 via the paper guide 218 and the discharge roller 219, thereby performing normal document copying. It is.

In addition, when copying both sides of a document, the gate 120 on the Oo side of the 1-separation unit 1 is driven to switch a solenoid (not shown) when the document is conveyed in the same way as in the case of copying a single-sided document as described above, and the copying of the first surface of the document is completed. conveyor belt 2
At the same time, the conveyor belt 211 is driven in the opposite direction to convey the original to the reversing paper path mechanism 110 configuring the separation unit 100 and reverse it. When the paper bus passes along the route and its leading end is detected by the second jam detection means 124,
In synchronization with this detection operation, the conveyor belt 211 is driven in the forward direction again after a certain period of time has elapsed, and the second aligning roller pair 107 starts rotating to transfer the original to the apparatus main body 1. The second surface of the document is then stopped at a predetermined exposure start position on the document placement glass 3 of the apparatus main body 1 by the document stopper 220 again for the second time. copying process is performed, and the first copy of the manuscript is
When copying the front side of an original, the original stopped at the exposure start position is turned over again and the copy is made.

Therefore, the operation of the apparatus main body 1 having the above-described configuration is performed by operating the operation panel 5 after setting the document tray on the document loading table 59 of the automatic document supply and discharge unit [4]. A document is set from the paper discharge unit device 4 onto the document placement glass 3. Meanwhile, the photoreceptor 20 rotates in this state, and the photoreceptor 2o is uniformly charged by the charging device 21. Next, the exposure lamp 6 of the exposure device 23
1 is lit, the first carriage 69 and the second carriage 70 move from the row in the figure to the right along the lower surface of the document placement glass 3, so that the document is set on the document placement glass 3. The document is scanned and exposed to slit light.
An electrostatic latent image corresponding to the original is formed on the photoreceptor 20.

The electrostatic latent image thus formed on the photoreceptor 20 is developed and visualized by either the upper developing unit 75 or the lower developing unit 76 of the developing device 24. In synchronization with the image forming operation, paper P automatically taken out from the standard cassette 6 or large-capacity cassette 7, or paper P manually fed from the manual paper feed table 30 on the top of the standard cassette 6 is placed between the aligning rollers. 34 to the image transfer section 31, and transfers the developer image previously formed on the photoreceptor 20 to the transfer device 2.
The image is transferred onto the paper P by the action of 5.

Next, the sheet P after the developer image has been transferred is peeled off from the photoreceptor 20 by the peeling device 26 and sent to the fixing device 35 via the conveyor belt 57 that constitutes a part of the sheet conveyance path 33. After the developer image is melted and fixed on the paper P, it is discharged onto the paper discharge tray 9 via a pair of paper discharge rollers 32, and the developer image on the paper P is The developer remaining on the photoconductor 20 after the transfer and peeling is scraped off and cleaned by the cleaning blade 80 of the cleaning device 27, and then the developer facing the static eliminator 28 is removed so that light can be applied to the photoconductor 20. The electrostatic memory is removed by the irradiation, thereby bringing the photoreceptor 20 into a normal state in which the next copying operation can be performed.

By the way, the large-capacity cassette 7 constituting the above-mentioned paper feeding means 8 has a built-in paper pushing means 300 according to the present invention, and this paper pushing means 300 is shown in FIGS. 5 to 12. The configuration is as shown in .

That is, as shown in FIGS. 5 to 7, the paper pusher 300 is a paper pusher provided on the inner bottom surface of the large-capacity cassette 7 via a rotation shaft 301 so as to be able to push up the paper upward and downward. A lifting plate 302, a spring 303 that supports the sheet lifting plate 302 from below and urges it upward with a predetermined lifting force, and the sheet lifting plate 302 is raised and lowered with the urging force of the spring 303. A link lever 304 to be moved, an idle gear 307 that is coaxially provided with a pinion gear 305 that engages with a gear 304a provided at one end of this link lever 304 via a one-way clutch 306, and a worm wheel 307a of this idle gear 307. The worm gear 308 meshes with the worm gear 308, the drive motor 309 rotates the worm gear 308, and the battery 401 connected to the drive motor 309 via a control circuit 4-00 is powered by a dry battery. The one-way clutch 306 is connected to the paper push-up plate 3
The pinion gear 305 can be freely rotated in the downward direction of 02, and can be maintained in a locked state in the upward direction.
has a spring force slightly stronger than the loaded weight of the paper P to be pushed up.

As a result, the drive motor 309 causes the spring 3 to
While loosening the spring force of 03, gradually press the paper push-up plate 3.
02 is driven upward, and the load on the drive motor 309 is reduced, thereby making it possible to save power consumption. At this time, by the deceleration means using the worm gear 308.

Since a large reduction ratio can be achieved, the entire device can be made compact, and since the worm gear 308 is used, the spring force of the spring 303 is not enough to drive the drive motor 309.
does not reverse, thereby making it possible to lock the paper push-up plate 302 at an appropriate raised position.

In addition, as shown in FIG. 6@ and FIG.
A paper height position detection sensor 402 that detects at the ll position is installed, and this paper height position detection sensor 402 has a hysteresis characteristic between 0N and OFF as shown in FIG. The 0N-OFF position differs depending on the direction in which the sheet P enters, thereby making it possible to detect the height position of the paper P with one sensor.

Furthermore, as shown in FIGS. 6, 10, and 11,
The paper push-up plate 302 of the large-capacity cassette 7 has through holes 40.
3 is provided, and this through hole 403 corresponds to the reflective sensor 11 installed at the bottom of the apparatus main body 1, and detects the "out of paper" state even when the paper pushing plate 302 is at the top dead center position. This eliminates the need to install a sensor to detect the state of "no paper on the large-capacity cassette 7 side," and the sensor position distance is also reduced at the top dead center of the paper push-up plate 302. Because it's small.

Detection is made easy.

That is, when the above-mentioned large-capacity cassette 7 is attached to the attachment part of the apparatus main body 1, as shown in FIG. The paper P is taken out in the same way as in the upper standard cassette 6 by vertically swinging the arm 44 of the paper taking out means (see Fig. 12), and as shown in Fig. 13, the height of the paper is increased. , when the installation height of the paper height position detection sensor 402 reaches H, the paper height position detection sensor 402 is turned on, the driving motor 309 is driven, and as shown in FIG. By gradually driving the cassette 302 upward in accordance with the amount of paper to be taken out while relaxing the spring force of the spring 303, which has a spring force slightly stronger than the loaded weight of the paper P to be pushed up, the cassette 302 is raised in the same way as the standard cassette 6 in the upper stage. This allows the paper P to be taken out.

Furthermore, FIG. 15 shows a state in which the standard cassette 6 is attached to the attachment part of the large-capacity cassette 7 of the apparatus main body 1, and as shown in FIG. 16, the insertion end side of the standard cassette 6 is A guide member 601 is provided on the side, and the guide member 601 is guided and supported by a support guide member (not shown) provided at the mounting portion of the large-capacity cassette 7 of the apparatus main body 1, so that the standard cassette 6 can be mounted. It is what it is. Further, 404 in the figure indicates the large-capacity cassette 7.
A display means consisting of an LED lamp installed on the top side of the
This display means 404 is connected to the battery 40 (not shown).
The battery 401 is connected to a means for detecting whether or not the battery 401 has a certain capacity, and when the capacity of the battery 401 falls below a certain capacity, a message to that effect can be displayed and checked.

[Effects of the Invention] As is clear from the above description, according to the present invention, a normal amount of paper can be stored in the apparatus main body in which image forming process constituent means such as charging, development, transfer, cleaning, and fixing are built. A paper feeding means consisting of a standard cassette for storing a large capacity of paper and a large capacity cassette for storing a large capacity of paper, and a paper feed means for taking out the paper in the standard cassette and the large capacity cassette at respective loading parts. The image forming apparatus is configured to take out sheets one by one by a take-out means, and the large-capacity cassette has a height of the sheets stored in the large-capacity cassette that is equal to the normal amount stored in a standard cassette. It has a built-in paper pushing means that operates to push up the paper when the height becomes lower than the height of the paper, and this paper pushing means pushes up the paper stored in the large capacity cassette through a pushing drive means using a drive motor. a paper push-up plate that pushes up the paper, and a spring that always biases and supports the paper push-up plate upward, and this spring is slightly stronger than the maximum weight of the paper stored in the large-capacity cassette. Since the paper pushing plate is configured to have a spring force and to raise the paper pushing plate while gradually loosening this spring force by driving the drive motor, the pushing up of the paper is assisted by the biasing force of the spring. This has the excellent effect of reducing the capacity of the drive motor and reducing power consumption.

[Brief explanation of the drawing]

FIG. 1 is an external view showing the overall configuration of an electronic copying machine as an image forming apparatus according to the present invention, FIG. 2 is a schematic longitudinal sectional front view, and FIG. 4 is a schematic explanatory diagram showing an enlarged view of the transport unit of the automatic document feed/discharge unit device; FIG. Figure 6 is a partially cutaway perspective view of a large capacity cassette;
The figure is a cross-sectional view of the main part of the paper pushing means, and Figures 8 and 9 show the installation state and detection operation state of a paper height position detection sensor that detects the height of paper installed in a large-capacity cassette, respectively. Explanatory diagrams, Figures 10 and 11 are explanatory diagrams of the detection means for detecting the out-of-paper state of large capacity cassettes.
Figures 2 to 14 are explanatory diagrams showing the state of paper removal;
5 and 16 are explanatory diagrams showing the state in which a standard cassette is attached to the large-capacity cassette attachment portion of the main body of the apparatus. 1... Apparatus main body, 2... Image forming process configuration means. 7...Paper feed cassette (large capacity cassette), 8...Paper feed means, 41...First paper take-out means (take-out roller) 45
...Second paper take-out means (take-out roller) 300.
...Paper push-up means, 302...Paper push-up plate. 303... Spring, 304... Link lever, 305... Binion gear. 306...One-way clutch. 307... Idle gear, 307a... Worm wheel, 308... Worm gear, 309... Drive motor. P...Paper. Applicant's agent Patent attorney Takehiko Suzue Figure 1 U02 78 Figure 9

Claims (1)

[Claims] A device that has built-in image forming process components such as charging, development, transfer, cleaning, and fixing, and consists of a standard cassette that stores a normal amount of paper and a large-capacity cassette that stores a large amount of paper. An image forming apparatus is provided with a paper feeding means, and the sheets in the standard cassette and the large-capacity cassette are taken out one by one by a paper take-out means consisting of a take-out roller provided in each mounting section, the image forming apparatus comprising: The cassette has a built-in paper pushing means that operates to push up the paper when the height of the paper stored in the large-capacity cassette becomes lower than the height of the normal amount of paper stored in the standard cassette. The paper push-up means includes a paper push-up plate that pushes up the paper stored in the large-capacity cassette via a push-up drive means using a drive motor, and a paper push-up plate that always urges the paper push-up plate upward. This spring has a spring force slightly stronger than the maximum weight of paper stored in the large-capacity cassette, and this spring force is gradually applied by driving the drive motor. An image forming apparatus characterized in that the paper pushing plate is raised while being loosened.