JPH01176732A - Image formation apparatus - Google Patents

Abstract

PURPOSE:To install a large-capacity paper feed cassette in a simple constitution by operating paper push-up means when the height of paper in the large-capacity cassette becomes lower to conduct paper take-out operation similar to take-out operation for paper in a standard cassette. CONSTITUTION:When a large-capacity paper feed cassette 7 is installed, paper P on a paper push-up plate 302 urged by a spring 303 is taken out by a take-out roller 45 of an arm 44 mounted on an apparatus main body in such a manner as to freely oscillate up and down in the same manner as paper in an upper standard cassette 6. When the height of paper P is decreased to a designated height, such a decrease is detected and the paper push-up plate 302 is gradually raised according to the amount of taken-out paper by a driving motor through a reduction mechanism while spring force of the spring 303 a little larger than the paper loading weight is reduced to continue taking out paper P in the same manner as in the upper standard cassette 6. Thus, the large-capacity paper feed cassette can be installed in such a manner as to take out paper similarly to paper taking-out for the ordinary standard cassette in a simple constitution.

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.

(Conventional Technique Is It?) Normally, in a PPC copying machine, the size of the paper is In addition to installing paper feed cassettes corresponding to the size of paper in multiple stages above and below in each loading section of the main body of the device, and storing frequently used paper sizes separately in the large-capacity paper feeding device, this large-capacity paper feeding device can be used. Some devices 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 is a problem in that the capacity of the drive motor must be increased, which inevitably increases the cost.

The present invention has been made under the above circumstances, and its purpose is to enable a large-capacity paper feed cassette to be installed in a simple configuration in the same way as paper is taken out from a standard cassette; An object of the present invention is to provide a small and inexpensive image forming apparatus.

[Structure of the invention] (Means for solving problems) One aspect of the present invention is to solve the above-mentioned problems.

Paper that consists of a standard cassette that stores a normal amount of paper and a large-capacity cassette that stores a large amount of paper in the main body of the device that has built-in image forming process constituent means such as charging, development, transfer, cleaning, and fixing. 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. However, it is configured such that the take-out roller of the paper take-out means performs the same take-out operation as the take-out operation of sheets housed in a standard cassette.

(Function) That is, the present invention incorporates a paper pushing means in a large capacity cassette that is attached to a mounting portion of the main body of the apparatus, and uses this paper pushing means to raise the height of the paper stored in the large capacity cassette. When the height of the paper becomes lower than the height of the normal amount of paper stored in the standard cassette, the paper is pushed up and the paper is taken out in the same way as the paper taken out of the standard cassette. This makes it possible to downsize a large-capacity paper feed cassette, and the means for pushing up the paper has a simple configuration.Furthermore, since the amount of paper that is pushed up is reduced, the capacity of the drive motor can be reduced. It becomes possible to make it smaller.

(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 top side thereof, there is provided an automatic document supply/ejection unit (described later) which sets the document on the document placement glass 3 and ejects the document from the document placement glass 3. In addition, there is an operation panel 5 on the front edge of the top surface.
is located.

On the right side of the apparatus main body 1 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 one 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 Hl of the upper standard cassette 6 (Hl<H2), while the fixed paper P is on the left side. A paper feed tray 9 for collecting paper is attached.

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 i'? 22
．． An exposure section 23a serving as an exposure device 23, a developing bag M24.
A transfer device 25, a peeling device 26, a cleaning device 27, a static eliminator 28, etc. are arranged in order, while paper is automatically fed from the paper feeding means 8 along the inner bottom of the upper part 1a. The paper P, or the paper P manually fed from the manual paper feed table 30 which also serves as the cover of the standard cassette 6, is transferred to the left side of the main body 1 of the apparatus via the image transfer section 31 between the photoreceptor 20 and the transfer device 25. A sheet conveyance path 33 leading to the sheet discharge tray 9 via a pair of sheet discharge rollers 32 provided at but,
Further, on the downstream side thereof, fixing devices 35 are arranged.

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, numeral 52 in FIG. 1 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 the paper P coming from.

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.

Next, the light transmitted through the lens 65 is transmitted to a fourth mirror 66,
The light is guided to the photoreceptor 20 via a fifth mirror 67 and a sixth mirror 68 in this order.

Then, the exposure lamp 6 surrounded by the reflector 60
1 and the first mirror 62 are mounted on a first carriage 69 that can freely move back and forth along the lower surface of the yX document mounting glass 3, and the second mirror 63 and the third mirror 64 are
are mounted on a second carriage 70 that moves in the same direction at half the speed of the first carriage 69,
By moving these first and second carriages 69 and 70 from the left to the right in the state shown in FIG. 2, the original set on the original placing glass 3 is scanned and exposed. An image corresponding to an original document is exposed on the body 20 by slit exposure.

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 i24 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 g135 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 to both upper and lower casings 88. 89, and the pair of paper ejection rollers 3 is located near the downstream side thereof.
2 and a paper discharge switch 90 are integrated.

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 photoreceptor 20 with light from the static eliminating lamp 95 via the green filter 96, and the erasing device! 22 is a large number of LEDs along the longitudinal direction of the photoreceptor 20.
is arranged so that it is possible to erase the charge in a portion corresponding to the area specified by the spot 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.

Below this conveyor belt 57, that is, the upper unit 1
A high-voltage transformer 58 is arranged at the bottom of each section a. 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 includes a separation unit 100 that constitutes a separation means for feeding, separating, and conveying the documents stacked on the document stacking table 59, and a separation unit 100 adjacent to the separation unit 100. The separating unit 100 is configured to stack originals to be transported on a document stacking table 59 and separate and invert the originals. The transport unit 200 is one separation unit 100
The document sheet ejected from the main body 1 is conveyed to an exposure position on the document placement glass 3 of the apparatus main body 1, and the document sheet 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 originals such as books. It has become. 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 layer of originals stacked on the Ha stacking table 59 one by one, and performs the separation and feeding process. Paper roller pair 10
4.105, and a first pair of aligning rollers 106 is provided on the downstream side of the pair of separating/feeding rollers 104 and 105.
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 reversing sheet path mechanism 110 is provided at an 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 document reversely conveyed from the 00 paper path 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 path 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.

Reference numeral 121 in the figure denotes a document detecting means 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.

Reference numeral 122 denotes a document detection sensor installed on the conveyance path between a pair of separation/feed rollers 104 and 105 that separate and feed the documents one by one and a first pair of aligning rollers 106;
Reference numerals 123 and 124 denote first and second jam detecting means installed apart from each other on the conveyance path between the first and second pair of aligning rollers 106 and 107, and this first jam detecting means 123 is the pair of separating/feeding rollers 104 and 105 and the first aligning roller pair 1.
06, the document jam, document width, document length, etc. are detected.
The jam detecting means 124 is configured to detect a jam of the document conveyed from the first aligner/growler pair 106 and a jam of the document conveyed from the reversing paper path mechanism 110. In the figure, reference numeral 125 indicates a third jam detecting means installed on the curved paper path of the reversing paper path mechanism 110, which detects a jam of a document that is reversed once.

As shown in detail in FIG. 4, the transport unit 200 includes a single paper bus 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 conveyance belt 211 contacts the document placement glass 3 of the apparatus 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, to explain the operation of the automatic document supply/discharge unit described above, first, when copying a single-sided document, when the document tray is set on the document stacking table 59 of the separation unit 100,
This "document present" state is detected by the document detecting means 121. In this state, the operation panel 6 of the copying machine main body 1
When the upper copy button is pressed, the document stacked on the document stacking table 59 is picked up by the pickup roller 103 inside the separation unit 100, which rotates and descends, and is sent to the separation/feed rollers 104 and 105. By the rotation of these pair of rollers 104 and 105, for example, a two-sheet document is separated one by one and sent to the downstream side. Then, when the leading edge of this 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 has elapsed, the pair of first and second aligning rollers 106 and 107 start rotating and send the original to the transport unit 200 side. At this time.

Said first and second aligning roller pair 106°10
7, the conveyor belt 2 of the conveyor unit 200
11 is driven, and the document sent from the separation unit 100 is conveyed to the upper part of the document placement glass 3 of the apparatus main body 1 by the drive of this conveyor belt 211, and the document is moved to the upper part of the document placement glass 3 of the apparatus main body 1 by the document stopper 220. is stopped at a predetermined exposure start position on the document placement glass 3. In this state, the apparatus main body 1 operates and starts copying the original. Then, the completion of such a copying process is completed by the apparatus main body 1.
When the copying operation is completed, the above-mentioned conveyor belt 211 is driven again, and the document that is stationary on the document placement glass 3 of the apparatus main body 1 is transferred to the pager guide 218 and the ejection roller 219. The documents are discharged and accumulated on the document discharge table 201 via the document discharge table 201, thereby performing normal copying of the document.

In addition, during double-sided copying of a document, the document is transported in the same manner as in the case of single-sided original copying described above, and when the copying of the first surface of the document is completed, the gate 120 on the 1-separation unit 100 side is switched and driven by a solenoid (not shown) to transport the document. belt 21
1, the conveyor belt 211 is driven in the opposite direction to convey the document backwards to the reversing paper path mechanism 110 that constitutes the separation unit 100 and reverse it. Pass on the paper path route.

When the leading end of the jam detecting means 124 detects the jam detecting means 124, the conveying belt 211 moves in synchronization with this detecting operation.
After a certain period of time has elapsed, the second aligning roller pair 107 starts rotating and transports the original onto the original placing glass 3 of the apparatus main body 1. In this way, the original is The second surface, which is the back side of the document, is stopped again at a predetermined exposure start position on the document placement glass 3 of the apparatus main body 1 by the document stopper 220, and the second copying process is executed. ,moreover.

When copying the first surface of an original, the original stopped at the exposure start position is turned over again and the copy is made.

The operation of the apparatus main body 1 having the above-mentioned configuration is performed by operating the operation panel 5 after setting a document on the document stacking table 59 of the automatic document supply and discharge unit device 4. A document is set from the paper unit device 4 onto the document placement glass 3. Meanwhile, in this state, the photoreceptor 20 rotates, and the photoreceptor 20 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 fused and fixed on the paper P, it is discharged onto the paper discharge tray 9 via a pair of paper discharge rollers 32. After the developer image is transferred and peeled off, the developer remaining on the photoreceptor 20 is scraped off and cleaned by the cleaning blade 8° of the cleaning device 27, and then the developer is removed from the photoreceptor 20 by facing the static eliminator 28. The photoreceptor 20 is irradiated with light to remove the electrostatic memory, 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 one-way clutch is composed of a worm gear 308 that meshes with the worm gear 308, a drive motor 309 that rotationally drives the worm gear 308, and a battery 401 connected to the drive motor 309 via a control circuit 400 and whose power source is a dry battery. 306 is a paper push-up plate 30
2, the pinion gear 305 can be rotated freely in the downward direction of paper P, and can be kept locked in the upward direction, while the spring 303 is slightly stronger than the loaded weight of the paper P to be pushed up. As a result, the drive motor 309 gradually drives the paper push-up plate 302 upward while loosening the spring force of the spring 303, and reduces the load applied to the drive motor 309. This makes it possible to reduce 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.

Further, as shown in FIGS. 6 and 8, the height H2 of the paper P stored in the large capacity cassette 7 is set to a height H2.
A paper height position detection sensor 402 that detects at the position (3) is installed.
As shown in Figure 9, it has a hysteresis characteristic between 0N and OFF, and the 0N and OFF positions differ depending on the direction in which the sensor enters.This allows one sensor to detect the paper P. This allows the height position to be detected.

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 is.

Corresponding to the reflective sensor 11 installed at the bottom of the apparatus main body 1, the paper push-up plate 302 is arranged so that it can detect the "out of paper" state even when it is at the top dead center. It is not necessary to install a sensor to detect the "out of paper" state on the capacity cassette 7 side, and since the sensor position distance is small even at the top dead center of the paper push-up plate 302, detection can be easily performed. ing.

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. By vertically swinging the arm 44 of the paper ejecting means, the paper P is ejected in the same way as in the upper standard cassette 6 (see FIG. 12). Then, as shown in FIG. 13, when the height of the paper reaches the installation height Hm of the paper height position detection sensor 402, the paper height position detection sensor 402 is turned on and the drive motor 309 is driven. Then, as shown in FIG. 14, while loosening 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 paper push-up plate 302 is gradually moved in accordance with the amount of paper to be taken out. By driving it upward, it is possible to take out the paper P in the same manner as in the standard cassette 6 in the upper stage.

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, one normal amount of paper can be stored in an apparatus main body in which image forming process constituent means such as charging, developing, transferring, cleaning, and fixing are built-in. 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 incorporates a paper push-up means that operates to push up when the paper becomes lower than the height of the paper, and causes the take-out roller of the paper take-out means to take out the paper in the same way as the take-out operation of paper stored in a standard cassette. With this configuration, a large-capacity paper feed cassette can be downsized, and the paper pushing means has a simple structure.Moreover, since there is less space to push up the paper, the capacity of the drive motor can be reduced. This has the excellent effect of being able to be made smaller.

[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 conveyance 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 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 a detection means for detecting the "out of paper" state of a large-capacity cassette.
Figures 2 to 14 are explanatory diagrams showing the state of paper removal;
5 and 16 are explanatory diagrams showing the state in which the standard cassette is attached to the large-capacity cassette attachment portion of the main body of the apparatus. 1...Device body. 2... Image forming process configuration means, 6... Standard cassette (first paper feed cassette), 7...
- Large capacity cassette (second paper feed cassette). 8...Paper feeding means. 41...first paper take-out means (take-out roller) 45
...Second paper take-out means (take-out roller) 300.
...Means for pushing up paper. 302...Paper push-up board. P...Paper, H,,H,,HIm...Paper height. Applicant's agent Patent attorney Suzue Takehiko 307a Chu 8 Illustration recommendation 9 Illustration

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. An image forming apparatus characterized in that the image forming apparatus is configured to cause a take-out roller of the paper take-out means to take out the paper in the same manner as the take-out operation of paper stored in a standard cassette.