JP2000038239A - Paper sheet detection device of image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet detection device of an image forming device capable of detecting paper sheet loaded on a bypass tray surely. SOLUTION: A paper sheet detection device of an image forming device is provided with a loading plate 86 incorporated in a main body 10, a lid member 82 supported in the main body 10 so as to turn freely, a paper sheet detection member 111 whose one end constitutes an operation part 112 arranged so as to come in and out from a second loading plate 102 of the lid member 82 and the other end constitutes a detection part 113 arranged so as to shield and open an opening for detection 116, an opening for lighting 115 for taking in light from the outside, and a paper sheet detection sensor 118 receiving light through openings for detection 107, 116, 117 when a paper sheet is loaded on the second loading plate 102.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet detecting device for an image forming apparatus, and more particularly to a sheet detecting device for detecting a sheet placed on a bypass tray or the like.

[0002]

2. Description of the Related Art Image forming apparatuses such as copiers, printers, and facsimile apparatuses are required to be reduced in size in order to save office space. For example, in a copying machine, a plurality of paper cassettes containing paper are prepared in accordance with the size of paper to be used, and each paper cassette is detachable from the apparatus. Also, on the top of the copier,
A document table on which a document is placed is provided. The paper placed on the platen is irradiated with light, and the light reflected from the document is converted into an electrical signal by a CCD sensor or the like, and the CCD is converted to an electric signal.
An electrostatic latent image is formed on the surface of the photosensitive drum based on a signal from the sensor, and the electrostatic latent image is visualized as a toner image by a developing device. Thereafter, the paper having the toner image formed on its surface is conveyed to a fixing device, and the toner image is heated and fused.

[0003] Sheets on which images are formed include B5 and B5.
Sizes such as 4, A4, and A3 are common, and the size of the document table is often adjusted to A3 so that the largest document of A3 size can be placed. Further, in many cases, the paper cassette mounting section in which the paper cassette is detachable can be mounted with a paper cassette capable of storing A3 size paper.

[0004] The paper pulled out from the paper supply cassette mounting section is conveyed to the image forming section via a paper feed path, and the sheet on which the toner image has been transferred on the surface in the image forming section is transported via the sheet discharge conveying path. To the fixing device, and is discharged to a paper discharge tray. Here, the document table and the paper feeding cassette mounting portion are arranged vertically so that they are almost overlapped in a plan view, and the paper feeding conveyance path, the image forming portion, and the paper discharging conveyance so that the paper conveyance direction is vertical. By devising the arrangement of the road and the fixing device, it becomes possible to provide a copying machine having an installation area slightly larger than the A3 size.

[0005] In this case, the paper drawn from the paper feed cassette is suddenly changed direction and conveyed to a vertically extending paper feed path. For this reason, cardboard, OHP sheets,
It is difficult to use special paper such as surface coated paper, so-called material paper, stored in such a paper feed cassette. Therefore, there is a configuration in which a bypass tray capable of storing material paper is provided, and a bypass transport path is configured so that the paper transported from the bypass tray to the image forming unit does not suddenly change its direction.

[0006]

In the above-mentioned image forming apparatus, the bypass tray is usually provided so as to protrude to the side of the apparatus. When using this bypass tray, paper is placed on the bypass tray protruding to the side of the apparatus, the paper feed position for feeding paper is designated to the bypass tray from the operation panel, and the start button is operated.

Therefore, in such an image forming apparatus, the bypass tray protrudes to the side of the apparatus main body, and the substantial installation area is larger than the occupied area of the apparatus main body by the bypass tray. It is conceivable that such a bypass tray is rotatably attached to the apparatus main body, and is opened to the side of the apparatus main body only when used. However, when the bypass tray is used, it is difficult to reduce the occupied area of the apparatus substantially in the same manner as described above, since the bypass tray is projected to the side of the apparatus.

In view of the above, it is conceivable to provide a bypass tray inside the apparatus main body. As described above, considering that the area occupied by the apparatus main body is limited to an area slightly larger than the A3 size, and that the paper conveyance path from the bypass tray is configured to prevent a sudden change in direction, the bypass tray is The size existing inside the apparatus main body is limited to an area in which A4R size paper can be placed.

In order to enable a paper feeder having a size larger than A4R in such a bypass tray built in the apparatus main body, a tray rotatably supported with respect to the apparatus main body is provided. It is conceivable that the paper is fed by feeding the paper while the paper is opened and protruded to the side of the apparatus main body. In this case, even when A3 size paper is placed on this bypass tray, the size of the tray can be configured so as to allow A4R size paper to be placed, and the size of the tray protrudes to the side of the apparatus main body. The size of the tray to be used can be made as small as possible.

A paper detection sensor such as a micro switch or a photoelectric switch is provided on the bypass tray.
The sheet is detected based on a signal detected by a sheet detection sensor according to the size of the sheet to be placed. However, as described above, in a bypass tray in which a part is built in the apparatus main body and a part is a tray rotatably supported by the apparatus main body, the bypass tray is movable with respect to the apparatus main body. It is necessary to provide a sheet detection sensor on the tray, and it is necessary to wire the sheet detection sensor through this movable part. Therefore, there is a possibility that the movable portion may be disconnected, and there is a problem that the reliability of the device is lacking.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a sheet detecting device of an image forming apparatus which can reliably detect a sheet placed on a bypass tray.

[0012]

A sheet detecting device of an image forming apparatus according to the present invention includes a first placing portion, a second placing portion, a sheet detecting member, and a sheet detecting sensor. The first placement unit places a sheet to be supplied to the image forming unit. The second placement unit is rotatably supported relative to the first placement unit on the upstream side of the first placement unit in the sheet conveyance direction, and is located at an open position that is located on an extension of the first placement unit. Locking is possible, and when locked at the release position, the rear end of the sheet placed on the first placing portion can be indicated. The sheet detecting member is displaced based on the size of the sheet placed on the first placing portion and the second placing portion when the second placing portion is at the open position. The paper detection sensor is provided on the first mounting portion, and detects displacement of the paper detection member.

A sheet detecting member provided on the second mounting portion;
The paper detection sensor provided in the first placement unit is electro-mechanically separated from the sheet detection sensor, and there is no possibility of disconnection or damage due to the movement of the second placement unit. Can be enhanced. Here, the second mounting section includes a lighting section for taking in light from the outside, and a first lighting section for taking in light taken from the lighting section.
A detection hole for allowing the sheet to pass to the receiver, and the sheet detecting member is rotatably supported by the second receiver,
It has an operating part that can appear and disappear on the surface of the mounting part, and a detecting part that can shield and open the detection hole in conjunction with the operating part, and when the paper is not present on the second mounting part, the operating part is The detection unit projects on the second placement unit and shields the detection hole, and when a sheet is present on the second placement unit, the operating unit determines the second position based on the weight of the sheet.
The detection unit may be configured to be submerged in the mounting unit and open the detection hole.

[0014]

FIG. 1 is a longitudinal sectional view of a copying machine to which an embodiment of the present invention is applied. The copying machine 1 has a main body 10 and a document holder 11 mounted on the upper part of the main body 10 so as to be openable and closable. An original platen 15 on which an original is placed is disposed on the main body 10 at an upper portion thereof. Inside the main body 10, an image forming unit 16 is provided at the left end as viewed from the front and substantially at the center in the vertical direction.
Further, a paper feed unit 17 for supplying a document to the image forming unit 16 is provided below.

The paper supply unit 17 is detachably attached to the main body 10 and stores paper supply cassettes 18 and 19 for storing paper.
And a stack bypass 20 provided thereabove. An optical system 21 for reading image information of a document placed on the document table 15 is provided below the document table 15. The optical system 21 includes a light source 22 for irradiating light to the surface of the document placed on the document table 15 and mirrors 23, 24, and 2 for deflecting light reflected from the surface of the document.
5 and a lens 2 for converging the light from the mirror 25
6 and an image sensor 27 such as a CCD sensor that receives light converged by the lens 26 and generates an image data signal corresponding to an original image.

The image forming section 16 has a photosensitive drum 30 on the surface of which an electrostatic latent image is formed.
0, a main charging device 31, a developing device 32,
It has a transfer roller 33 and a cleaning device 34. The main charging device 31 is a device for charging the surface of the photoconductor drum 30, and is disposed diagonally above and to the right of the photoconductor drum 30. The photosensitive drum 3 is disposed diagonally below and to the right of the photosensitive drum 30 with a predetermined gap from the main charging device 31.
A developing device 32 for forming a toner image on the image sensor 0 is disposed. The developing device 32 stores toner inside, and visualizes the electrostatic latent image formed on the photosensitive drum 30 by the toner. The transfer roller 33 is a device for transferring the toner image on the photosensitive drum 30 to a sheet, and is disposed on the left side of the photosensitive drum 30. The cleaning device 34 is a device for removing residual toner and the like on the surface of the photoconductor drum 30.
0.

On the right side of the photosensitive drum 30, a laser unit 35 for forming an electrostatic latent image on the peripheral surface of the photosensitive drum 30 is provided. The laser unit 35 forms an electrostatic latent image on the peripheral surface of the photosensitive drum 30 based on an image data signal obtained from the image sensor 27. The paper feed unit 17 includes a vertical transport path 41 for transporting paper from each of the paper cassettes 18 and 19 toward the image forming unit 16 and a bypass transport path for transporting paper from the stack bypass 20 to the image forming unit 16. 42 are provided. Each paper cassette 1
Pickup rollers 43, 4 for taking out the stored paper are provided in the stack bypasses 8, 19 and the stack bypass 20.
4, 45 and a pair of paper feed rollers 46, 47, 48 for feeding the paper one by one to the transport path. The vertical transport path 41 is provided with pairs of transport rollers 49 and 50, and the bypass transport path 42 is provided with a pair of transport rollers 51. The vertical transport path 41 and the bypass transport path 42 join below the transfer position where the photosensitive drum 30 and the transfer roller 33 face each other. At the confluence, a registration roller 52 for stopping the conveyed sheet at a predetermined position is provided.

Above the photosensitive drum 30 and the transfer roller 33, a fixing device 53 for fusing and fixing the toner transferred onto the paper is provided. The fixing device 53
A heating roller 54 having a built-in heater and a pressure roller 55 pressing the heating roller 54 are provided. The sheet is nipped between the rollers and transported, and the toner image formed on the surface of the sheet is heated and fixed. Things.

Further above the fixing device 53, a branch 5
6 are provided. On the right side of the branch portion 56, a discharge tray 57 for discharging sheets via a discharge roller pair 60 is provided.
And a discharge roller pair 6 disposed above the discharge tray 57.
1 and a sub-eject tray 58 from which sheets are ejected. A switchback unit 59 for reversing the sheet at the time of double-sided copying is provided at the lower left of the branch unit 56.
Is arranged. The branching portion 56 is provided with a branching claw 62 for switching the sheet conveying direction between the direction of the discharge tray 57 and the direction of the switchback portion 59. Branch claw 62
Two branch claws 63 and 64 are provided on the left side of. Below the two branch claws 63 and 64, a switchback transport path 65 for guiding a sheet to a switchback section 59 is provided.
A sub-tray conveyance path 66 for guiding the sheet to the sub-discharge tray 58 is provided above, and a sheet is conveyed to a finisher (not shown) such as a sorter or a staple sorter between the two branch claws 63 and 64. A finisher transport path 67 is provided. Branch claws 63, 64
Switches the transported paper to the switchback transport path 65,
It is possible to switch so as to guide to either the sub-tray conveyance path 66 or the finisher conveyance path 67. [Stack Bypass] The details of the stack bypass 20 will be described with reference to FIGS.

The stack bypass 20 has a base 81 and a lid member 82 rotatably supported by the base 81. The base 81 is provided with a mounting plate 86 on which a sheet is mounted on the upper surface.
And a pickup roller 45 positioned above the left end of the mounting plate 86 for pulling out sheets.
And a sheet feed roller pair 48 for sending out sheets one by one to the transport path. A guide surface 87 for guiding a sheet toward the bypass conveyance path 42 is provided on the left side of the sheet feeding roller pair 48.
Is provided. Further, both sides of the base 81 (the main body 10)
, The guided rail 84 and the guide roller 85
And guided portions 83, 83 having the following. Correspondingly, a guide rail 72 having a guide roller 73 for guiding the lower surface of the guided rail 84 is provided inside the main body 10.
Is provided. The base 81 is guided by the guide rail 72 and can be pulled out from an opening 71 provided on the right side of the main body 10.

The mounting plate 86 is provided with a guide groove 88, and partition plates 89, 89 for engaging with the guide groove 88 and aligning the sheet in the left-right direction are attached.
Further, the mounting plate 86 is rotatable with respect to the base 81 via the support shaft 90, and is urged in a direction to push up the leading end position of the stored paper upward. In this example, a spring 91 is provided on the lower surface of the left end of the mounting plate 86 to urge the left end of the mounting plate 86 upward.

On the upper surface of the mounting plate 86, a cam member 92 is provided.
Is in contact. The cam members 92 are attached to both ends of the rotation shaft of the pickup roller 45, and are in contact with the upper surface of the mounting plate 86 at the downstream end in the sheet conveyance direction. When not driven, the cam member 92 separates the upper surface of the mounting plate 86 from the pickup roller 45 against the urging force of the spring 91 as shown in the figure. Also, the cam member 9
In No. 2, the cam surface rises with rotation. Accordingly, the mounting plate 86 is configured to move to a position where the upper surface approaches or presses against the pickup roller 45 by the urging force of the spring 91.

The lid member 82 is rotatably supported at the right end of the base 81 so that the opening 71 can be closed when the base 81 is stored at a predetermined position in the main body 10. The paper stored in the stack bypass 20 is
The paper is conveyed to the image forming unit 16 via the bypass conveyance path 42 without a sudden change in direction. Therefore, the stack bypass 20 is suitable for feeding so-called material paper such as thick paper, OHP sheet, or surface coated paper to the image forming unit 16.

The stack bypass 20 accommodates A4-size paper on the mounting plate 86, and
Can be closed. Since it is considered that A4 size is often used as a normally used paper size, if such a paper is placed on the loading plate 86 and the lid member 82 is closed,
When paper is set on a so-called bypass tray, there is no portion protruding to the side of the main body 10. Furthermore, since the stack bypass 20 is disposed at a position where the stack bypass 20 overlaps the paper feed cassettes 18 and 19, the paper discharge tray 57, the sub tray 58, and the document table 15, the installation area can be minimized.

Further, since the stack bypass 20 can be pulled out from the opening 71 provided on the right side of the main body 10, the work of setting the paper on the mounting plate 86 becomes easy, and the Setting is easy even for small-sized paper. Stack bypass 2
When pulling out 0 to the side of the main body 10, the pickup roller 45, the sheet feeding roller pair 48, the mechanism for vertically moving the mounting plate 86, and the like are integrally pulled out. Does not impair. [Paper Detecting Means] As shown in FIG. 4, the lid member 82 is rotatably supported by the main body 10 by the support shaft 101. The lid member 82 can be closed with respect to the main body 10 as shown by a two-dot chain line. When the lid member 82 is opened as shown by a solid line, it is located on the extension of the mounting plate 86. To be locked.

The cover member 82 has a second placement plate 102 on which sheets can be placed continuously with the placement plate 86 when the cover member 82 is opened. Further, the lid member 82 includes an outer plate 103 that integrally forms a side wall of the apparatus main body with the side wall of the main body 10 when in the closed state, an upper plate 104 that is located on the upper side when in the closed state, and a lower position. And a front and rear side plate (not shown) located in front and rear. Also,
Inside the lid member 82, provided in a direction perpendicular to the paper surface,
A partition plate 106 having a detection opening 107 at the center is provided. Thus, the lid member 82 has an internal hollow surrounded by the second mounting plate 102, the outer plate 103, the upper plate 104, the lower plate 105, and the front and rear plates,
This internal hollow is partitioned by the partition plate 106,
The hollow portion 108 and the second hollow portion 109 are configured.

An operation opening 110 is formed at a position substantially at the center of the second mounting plate 102 and at a position located in the first hollow portion 108. The opening 110 for operation is provided with a sheet detection member 111. This sheet detecting member 111
Is an operating part 112 arranged at one end so as to be able to protrude and retract from the operating opening 110, and a multi-end side constitutes a detecting part 113 capable of shielding and opening the detecting opening 107 of the partition plate 106. It is rotatably attached to the lid member 82 through the intermediary.

The upper plate 104 is provided with a lighting opening 115 for taking in light into the first hollow portion 108. The light introduced into the first hollow portion 108 from the lighting opening 115 is transmitted to the second hollow portion 109 through the detection opening 107 when the detecting portion 113 of the sheet detecting member 111 opens the detecting opening 107. Will flow into The lower plate 105 is provided with a detection opening 116 that allows the light that has flowed into the second hollow portion 109 to pass through to the main body 10.

On the main body 10 side, a detection opening 117 is provided at a position corresponding to the detection opening 116. Inside the detection opening 117, a paper detection sensor 118 that is a photoelectric conversion element such as a photodiode or a phototransistor that detects light and outputs a detection signal is disposed. Although not shown here, the cover member 82 is
An open / closed state detection sensor for detecting whether an open state or a closed state with respect to 0 is provided. In this open / closed state detection sensor, for example, a microswitch configured to press the actuator when the lid member 82 is closed can be provided on the main body 10 side, and the position of the lid member 82 is photoelectrically converted. It is also possible to configure to detect by an element.

In the stack bypass 20 described above, when there is no sheet on the cover member 82 with the cover member 82 opened, the operating portion 112 of the sheet detecting member 111
Is in a state of protruding above the second mounting plate 102,
The detection unit 113 shields the detection opening 107 of the partition plate 106. As a result, the first opening
The light introduced into the hollow portion 108 is transmitted to the detection opening 107.
, The paper detection sensor 118 does not output a detection signal.

The paper is placed on the lid member 82,
When there is a sheet on the operation section 112 of the sheet detection member 111, the operation section 112 determines whether the second mounting plate 10
2 so as to be immersed. Along with this, the sheet detecting member 111 rotates around the support shaft 114 and the detecting unit 11
3 makes the detection opening 107 of the partition plate 106 open. In this case, the light taken in from the lighting opening 115 is
The sheet reaches the sheet detection sensor 118 via the detection openings 107, 116, and 117. Thus, the sheet detection sensor 118 outputs a detection signal indicating that a sheet is present on the second mounting plate 102 of the cover member 82.

Further, when the cover member 82 detects that the cover member 82 is closed by the open / closed state detection sensor, the detection signal of the sheet detection sensor 118 can be ignored. As described above, it is possible to easily and reliably detect whether or not there is a sheet on the second mounting plate 102 when the cover member 82 is in the open state. At this time, the paper detection sensor 118 is provided on the main body 10 side, and there is no need to perform wiring via a movable portion, and disconnection and mechanical failure can be minimized. If the operating portion 112 of the sheet detection member 111 is disposed at a position where the trailing edge of the A3 size sheet is detected, the size of the sheet placed on the stack bypass 20 is changed to A3 by the detection signal of the sheet detection sensor 118. It is possible to easily determine whether the sheet is of a size or smaller.

[0033]

According to the present invention, the sheet detecting member provided on the second placing portion and the sheet detecting sensor provided on the first placing portion are electro-mechanically separated. 2 There is no risk of disconnection or damage due to the movement of the mounting part,
The reliability of the detection can be enhanced, and the detection of the presence or absence of the sheet and the detection of the sheet size can be reliably performed.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a copying machine employing an embodiment of the present invention.

FIG. 2 is an explanatory view of a main part.

FIG. 3 is a perspective view thereof.

FIG. 4 is an explanatory view of a main part.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Main body 20 Stack bypass 82 Lid member 86 Mounting plate 101 Support shaft 102 2nd mounting plate 103 Outer plate 104 Upper plate 105 Lower plate 106 Partition plate 107 Detection opening 108 First hollow part 109 Second hollow part 110 Operating Opening 111 Paper detection member 112 Actuator 113 Detection unit 114 Support shaft 115 Lighting opening 116 Detection opening 117 Detection opening 118 Paper detection sensor

Continued on the front page F-term (reference) 2C058 AB02 AD03 AD04 AD06 AE02 AE04 AE09 AF06 GB04 GB12 GB17 GB30 GB46 2C059 AA02 AA49 AA54 2H072 AA09 AA12 AA23 HA04 HA09 3F048 AA02 AA04 AA05 AB01 BA02 BB09 BB10 FB03 FB03 FB03 HD07 KB20 MA03 MA09 MA23

Claims (2)

[Claims] A first placement unit on which a sheet to be supplied to an image forming unit is placed; and a first placement unit upstream of the first placement unit in a sheet transport direction.
The first mounting portion is rotatably supported by the mounting portion and can be locked at an open position located on an extension of the first mounting portion, and the first mounting portion is locked at the release position. A second placing portion capable of indicating a trailing end of a sheet placed on the first placing portion, and placing the second placing portion on the first placing portion and the second placing portion when the second placing portion is at an open position. A sheet detection device for an image forming apparatus, comprising: a sheet detection member that is displaced based on the size of a sheet that has been subjected to the detection; 2. The lighting device according to claim 1, wherein the second mounting unit includes a lighting unit that receives light from the outside, and a light that is received from the lighting unit.
A detection hole that allows the sheet to pass through to the mounting portion, wherein the paper detection member is rotatably supported by the second mounting portion and is capable of appearing and retracting on the surface of the second mounting portion. And a detection unit capable of closing and opening the detection hole in conjunction with the operation unit, wherein the operation unit is located on the second placement unit when there is no paper on the second placement unit. And the detection unit shields the detection hole, and when a sheet is present on the second placement unit, the operating unit sinks into the second placement unit due to the weight of the sheet and the detection unit Open the detection hole,
A sheet detection device for an image forming apparatus according to claim 1.