JP2015129803A - Open/closed state detection mechanism and image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect whether a conveyance guide arranged inside a sheet conveyance apparatus and sheet stacking means are opened or closed by means of one piece of detection means, thereby reducing costs for an opened/closed state detection mechanism.SOLUTION: A opened/closed state detection mechanism includes: a second push switch 72 for detecting whether a conveyance guide 70 and a manual feed tray 60 are opened or closed; a conveyance guide detection lever 54 which is brought into contact with or separated from the second push switch 72 according to the open/closed state of the conveyance guide 70; and a manual feed tray detection lever 73 which is brought into contact with or separated from the second push switch 72 according to the open/closed state of the manual feed tray 60. When a duplex unit 50 is closed, the conveyance guide detection lever 54 is positioned so as not to come into contact with the second push switch 72. When the duplex unit 50 is opened, the manual feed tray detection lever 73 is positioned so as not to come into contact with the second push switch 72.

Description

  The present invention relates to an open / close detection mechanism used in a sheet conveying device provided in an image forming apparatus main body so as to be openable / closable, and an image forming apparatus including the open / close detection mechanism.

2. Description of the Related Art Conventionally, there is known an image forming apparatus including a double-sided unit, which is a paper conveying device for supporting double-sided printing, in an outer portion of an image forming apparatus main body. The duplex unit is configured to be openable and closable with respect to the image forming apparatus in order to facilitate the removal of the sheet in the transport path and the maintenance in the apparatus when a paper jam occurs. Further, a path for reversing and conveying the printed paper is provided inside the duplex unit, and a conveyance guide is disposed on the image forming apparatus side with respect to this path.
The conveyance guide is supported so as to be rotatable with respect to the duplex unit. When a paper jam occurs, the conveyance guide can be opened and closed to remove the paper remaining in the conveyance path.

Further, the image forming apparatus includes a paper feed cassette for accommodating standard size paper, and manual feed for printing on paper of a size that cannot be accommodated in the paper feed cassette, or a small number of paper. And a paper feeding device. A sheet feeding unit of the manual sheet feeding device is provided inside the duplex unit, and a manual tray that is a sheet stacking unit of the manual sheet feeding device is provided to be openable and closable at an outer portion of the duplex unit.
The duplex unit, the conveyance guide, and the manual feed tray are provided with an open / close detection mechanism so that a user can remove a paper jam or can detect an open / close state.

  The open / close detection mechanism of the image forming apparatus includes dedicated detection means for detecting the open / closed state of the paper transport device, detecting the open / closed state of the paper stacking unit, and detecting the open / closed state of the transport guide in the paper transport device. Is detected. This detection means requires a detection switch and a harness for communicating the detection signal of the detection switch to the control board, and there is a problem that it is costly to detect the open / closed state of each open / close mechanism. .

  The present invention has been made in view of the above problems, and an object of the present invention is to detect an open / closed state of a transport guide and a paper stacking unit provided inside a paper transport device by one detection unit, and to detect an open / close detection mechanism. It is an object to provide an open / close detection mechanism capable of reducing the cost and an image forming apparatus including the open / close detection mechanism.

In order to achieve the above object, a first aspect of the present invention is a sheet conveying apparatus that can be opened and closed on an image forming apparatus main body, a conveying guide that is supported by the sheet conveying apparatus so as to be opened and closed, and an outer portion of the sheet conveying apparatus. In an open / close detection mechanism used in an image forming apparatus provided with a paper stacking unit supported in an openable / closable manner,
Detection means for detecting the open / close state of each of the transport guide and the paper stacking means, a first detection member that is brought into contact with and separated from the detection means in response to opening / closing of the transport guide, and A second detection member that is brought into contact with and separated from the detection means in response to opening and closing, and when the paper transport device is in a closed state, the first detection member is brought into a position that does not contact the detection means, and When the paper transport device is in an open state, the second detection member is positioned so as not to contact the detection means.

  According to the present invention, there is an excellent effect that the open / close state of the transport guide and the paper stacking unit in the paper transport device can be detected by one detection unit, and the cost related to the open / close detection mechanism can be reduced.

1 is a schematic configuration diagram of a full-color printer according to an embodiment. FIG. 3 is an explanatory diagram of a duplex unit in the full color printer. FIG. 6 is an explanatory diagram showing an opening operation of a manual feed tray in the full color printer. It is explanatory drawing which shows opening operation | movement of the duplex unit in the same full color printer. FIG. 6 is an explanatory diagram illustrating an opening operation of a duplex unit and a manual feed tray in the full color printer. FIG. 6 is an explanatory diagram illustrating an opening operation of a duplex unit and a conveyance guide in the full color printer. FIG. 6 is an explanatory diagram illustrating an opening operation of a duplex unit, a conveyance guide, and a manual feed tray in the same full color printer.

An embodiment of an image forming apparatus according to the present invention will be described.
FIG. 1 is a configuration diagram illustrating an outline of a full-color printer which is an example of an image forming apparatus according to the present embodiment.
The full-color printer includes an intermediate transfer belt 11 that is an intermediate transfer body as an image carrier that is stretched over a plurality of rollers, at a substantially central portion of the apparatus main body 1. Four image forming units 10M, 10C, 10Y, and 10Bk are provided along the belt surface of the intermediate transfer belt 11 facing downward in the vertical direction.

  Each of the image forming units 10M, 10C, 10Y, and 10Bk includes a photosensitive drum 2 as a latent image carrier. Around these photosensitive drums 2, a charging device, a developing device, a cleaning device, and the like are arranged, respectively. Further, primary transfer rollers 12 as primary transfer means are provided inside the intermediate transfer belt 11 at positions facing the respective photosensitive drums 2.

  An optical writing device 14 is provided below each of the image forming units 10M, 10C, 10Y, and 10Bk. Although not shown, the optical writing device 14 has a polygon mirror, a group of mirrors, etc., and irradiates the surface of the photosensitive drum 2 of each color image forming unit with light-modulated laser light.

  A two-stage sheet cassette 15 is set at the lower part of the apparatus main body 1, and sheet feeding means 16 corresponding to each sheet cassette is provided. In order to convey an image recording sheet such as transfer paper (hereinafter referred to as “paper”) fed by the paper feeding means 16, a pair of conveyance rollers 17 is provided. A registration roller pair 18 is provided above the conveyance roller pair 17 (on the downstream side in the sheet conveyance direction). A secondary transfer roller 19 that functions as a secondary transfer unit is disposed above the registration roller pair 18, and the secondary transfer roller 19 is one of the rollers that stretch the intermediate transfer belt 11. It is provided so as to face a certain secondary transfer counter roller 13.

  A fixing device 20 is provided downstream of the secondary transfer roller 19 in the sheet conveyance direction. A switching claw 21 for switching the paper transport direction is disposed above the fixing device 20. The switching claw 21 is switched by an actuator such as a solenoid (not shown).

  Further, the upper surface of the apparatus main body 1 has a two-stage discharge tray 30, and a pair of discharge rollers 29 for discharging paper to the lower stage 30 a of the discharge tray is located on the upper left side of the fixing device 20 in the drawing. Is located. Above the pair of paper discharge rollers 29, a pair of paper discharge rollers 31 for discharging the paper to the upper stage 30b of the paper discharge tray is provided so as to be able to rotate forward and backward.

In addition, a duplex unit 50 as a sheet conveying device is provided on the side of the apparatus main body 1.
The duplex unit 50 is formed with a part of a refeed path 52 for refeeding the inverted paper. The re-feeding path 52 is provided with a discharge roller pair 31 for discharging the sheet to the upper stage 30b of the discharge tray as a starting point and an end point at a point where it joins the sheet conveyance path before the registration roller pair 18. . A pair of transport rollers 26, 27, and 28 are arranged at positions that divide the refeed path 52 in the duplex unit into four equal parts.

Further, the duplex unit 50 includes a manual sheet feeder, and a manual tray 60 as a paper stacking unit of the manual sheet feeder is disposed on a side surface of the duplex unit 50 with respect to the duplex unit 50 with a rotation shaft 61 as a fulcrum. It can be opened and closed.
In the duplex unit 50, a sheet feeding unit 65 including a calling roller 62, a supply roller 63, and a separation roller 64 is provided for feeding sheets from the manual feed tray 60. Further, the paper conveyance path from the manual feed tray 60 joins the paper conveyance path from the paper feed cassette 15 on the downstream side of the registration roller pair 18 in the paper conveyance direction.
The duplex unit 50 will be described in detail later.

An image forming operation by the full color printer will be described.
The photosensitive drums 2 of the image forming units 10M, 10C, 10Y, and 10Bk are rotated in the clockwise direction in the figure by driving means (not shown), and the surface of the photosensitive drum 2 is uniformly charged to a predetermined polarity by a charging device. Is done. The charged photosensitive drum surface is irradiated with laser light from the optical writing device 14, thereby forming an electrostatic latent image on the photosensitive drum surface. At this time, the image information exposed to each photosensitive drum 2 is single-color image information obtained by separating a desired full-color image into magenta, cyan, yellow, and black color information. Each color toner is applied from the developing device to the electrostatic latent image formed in this way, and visualized as a toner image.

  Further, the intermediate transfer belt 11 is driven counterclockwise in the drawing as indicated by an arrow in FIG. 1, and from each photosensitive drum 2 by the action of each primary transfer roller 12 in each of the image forming units 10M, 10C, 10Y, and 10Bk. The respective color toner images are sequentially superimposed and transferred onto the intermediate transfer belt 11.

  On the other hand, paper is selectively fed from the paper feed cassette 15 or the manual feed tray 60, and the toner image carried on the intermediate transfer belt 11 is timed by the registration roller pair 18 toward the secondary transfer unit. Sent out. When the paper on which the toner image has been transferred by the secondary transfer section passes through the fixing device 20, the toner image is melted and fixed on the paper by heat and pressure. The fixed transfer material is discharged to a discharge tray 30 formed on the upper surface of the apparatus main body 1 by a discharge roller pair 29.

When printing on both sides of the sheet, the sheet having the toner image fixed on one side of the sheet is conveyed toward the pair of discharge rollers 31 that can rotate forward and backward by appropriately switching the switching claw 21. At this time, the paper discharge roller pair 31 is rotated in the forward direction (clockwise in FIG. 1). When the trailing edge of the paper conveyed toward the upper tray 30b by the paper discharge roller pair 31 is detected by the sensor 40, the paper discharge roller pair 31 is rotated in the reverse direction (counterclockwise in FIG. 1). The sheet is fed into the refeed path 52. The sheet is conveyed in the refeed path 52 by the conveying roller pairs 26, 27, and 28, and further sent to the registration roller pair 18.
In this way, the sheet switched by the pair of discharge rollers 31 that can rotate forward and backward is conveyed through the refeed path 52, so that the front and back of the sheet are reversed. Then, the toner image is transferred from the intermediate transfer belt 11 to the back side of the paper, and the back side image is fixed by the fixing device 20, whereby the paper carrying the images on both the front and back sides is discharged to the paper discharge tray 30, and the double-sided printing is performed. Complete.

The duplex unit of the full-color printer will be described in detail.
FIG. 2 is an enlarged view of a main part of the duplex unit in the full-color printer.
The double-sided unit 50 is provided so as to be swingable about a rotation shaft 51 provided at the lower part thereof, and can be opened and closed with respect to the apparatus main body 1.
The double-sided unit 50 includes a manual feed tray 60, a paper feed unit 65 of the manual feed tray 60, and the like in addition to the conveyance guide 70 that forms a part of the refeed path 52 indicated by a broken line in the drawing.

The conveyance guide 70 supports the driven rollers 26 a, 27 a, and 28 a of the conveyance roller pairs 26, 27, and 28, and can be opened and closed with respect to the duplex unit 50 with the rotation shaft 71 as a fulcrum. The refeed path 52 can be opened by opening and closing the transport guide 70, but a stopper member (not shown) is provided, and the transport guide 70 cannot be rotated beyond a predetermined angle. (See Figure 5)
Further, when the duplex unit 50 is in the closed state, the conveyance guide 70 is configured to be sandwiched between the apparatus main body 1 and the duplex unit 50 to be in the closed state.

A configuration of the open / close detection mechanism according to the duplex unit will be described.
The open / close detection mechanism includes a push switch 3 (hereinafter referred to as a first push switch) that detects an open / closed state of the duplex unit 50 in the apparatus main body 1. In addition, a push switch 72 (hereinafter referred to as a second push switch) is provided in the conveyance guide 70 as a detection unit that detects the open / closed state of the manual feed tray 60 and the conveyance guide 70 in accordance with the opening / closing of the duplex unit 50. Yes. Further, the double-sided unit 50 is provided with a convex portion 53 that contacts and separates from the first push switch 3 in accordance with opening and closing of the double-sided unit 50.

The opening / closing detection mechanism includes a conveyance guide detection lever 54 that detects opening / closing of the conveyance guide 70 as a first member that operates the second push switch 72.
The conveyance guide detection lever 54 is supported by the double-sided unit 50 with the rotation shaft 55 as a fulcrum, and the tip is provided so as to be able to contact and separate from the outer surface of the second push switch 72. And it is pushed to the apparatus main body side by the urging means 56 provided in the duplex unit 50.
Further, as a member related to the conveyance guide detection lever 54, a convex portion 4 that comes in contact with and separates from the conveyance guide detection lever 54 according to opening and closing of the duplex unit 50 is provided in the apparatus main body 1.

Further, the open / close detection mechanism includes a manual feed tray detection lever 73 that detects opening / closing of the manual feed tray 60 as a second detection member that operates the second push switch 72.
The manual feed tray detection lever 73 is supported by the conveyance guide 70 with a rotation shaft 74 as a fulcrum, and a tip portion is provided so as to be able to contact and separate from the outer surface of the apparatus body of the second push switch 72. Then, it is pushed to the outside of the apparatus main body by an urging means 75 provided in the conveyance guide 70.
Further, as a member related to the manual feed tray detection lever 73, a convex shape portion 66 that does not block the refeed path 52 and can be brought into contact with and separated from the manual feed tray detection lever 73 according to opening and closing of the manual feed tray 60 is provided in the manual feed tray 60. Is provided.

  Detection signals transmitted from the first push switch 3 and the second push switch 72 are received by a control unit (not shown) provided in the apparatus main body 1. The control unit receives the detection signal and displays information on an operation panel (not shown) provided in the apparatus main body 1.

The opening / closing detection operation related to the duplex unit 50 will be described with reference to FIGS.
First, opening / closing detection of the manual feed tray 60 will be described with reference to FIGS.
FIG. 2 shows a state where the duplex unit 50 and the manual feed tray 60 are closed.
Since the duplex unit 50 is closed with respect to the apparatus main body 1, the first push switch 3 is pressed by the convex portion 53 provided in the duplex unit 50 and turned on. Closed state is detected.

  At this time, since the duplex unit 50 and the manual feed tray 60 are closed, the manual feed tray detection lever 73 is pushed toward the apparatus main body by the convex portion 66 provided on the manual feed tray 60. Then, the second push switch 72 is pushed by the manual feed tray detection lever 73 and is turned on, and the closed state of the manual feed tray 60 is detected.

FIG. 3 is an explanatory diagram showing a state in which the manual feed tray 60 is opened with respect to the duplex unit 50 from the state of FIG.
When the manual feed tray 60 is opened from the state of FIG. 2, the convex portion 66 provided on the manual feed tray 60 is released from the manual feed tray detection lever 73. Further, the manual feed tray detection lever 73 is pushed to the outside of the main body by the urging means 75 provided in the conveyance guide 70, and the manual feed tray detection lever 73 is released from the second push switch 72. Then, the second push switch 72 is turned off, and the open state of the manual feed tray 60 is detected.

At this time, since the closed state of the conveyance guide 70 is determined because the duplex unit 50 is closed, the second push switch 72 does not need to detect the open / closed state of the conveyance guide 70. That is, when the duplex unit 50 is closed, the second push switch 72 only needs to detect the open / closed state of the manual feed tray 60.
In the present embodiment, when the duplex unit 50 is in the closed state, the conveyance guide detection lever 54 is pushed to the outside of the apparatus main body by the convex portion 4 provided in the apparatus main body 1 and is not in contact with the second push switch 72. Be released. Thus, the second push switch 72 can detect only the open / closed state of the manual feed tray 60.

Next, detection of the open / closed state of the conveyance guide 70 will be described with reference to FIGS.
FIG. 4 is an explanatory diagram showing a state in which the duplex unit 50 is opened with respect to the apparatus main body 1 from the state of FIG.
When the duplex unit 50 is opened with respect to the apparatus main body 1, the convex portion 53 provided in the duplex unit 50 is separated from the first push switch 3, the first push switch 3 is turned off, and the duplex unit 50 is turned off. Detect open state.

  At the same time, the conveyance guide detection lever 54 is released from the convex portion 4 provided in the apparatus main body 1 by opening the duplex unit 50. Then, the conveyance guide detection lever 54 is pushed toward the apparatus main body by the urging means 56 provided in the duplex unit 50, and the second push switch 72 is pushed. Thus, it is detected that the second push switch 72 is turned on and the conveyance guide 70 is closed.

FIG. 5 is an explanatory diagram showing a state in which the manual feed tray 60 is opened with respect to the duplex unit 50 from the state of FIG.
When the manual feed tray 60 is opened from the state of FIG. 4, the convex portion 66 provided on the manual feed tray 60 is released from the manual feed tray detection lever 73. Then, the manual feed tray detection lever 73 is separated from the second push switch 72 by the biasing means 75 provided in the conveyance guide 70. At this time, since the conveyance guide detection lever 54 presses the second push switch 72 due to the closed state of the conveyance guide 70, the open state of the manual feed tray 60 is not detected by the second push switch 72.

FIG. 6 shows a state where the conveyance guide 70 is opened with respect to the duplex unit 50 from the state of FIG.
When the conveyance guide 70 is opened from the state of FIG. 4, the second push switch 72 is released from the conveyance guide detection lever 54. At the same time, the manual feed tray detection lever 73 is released from the convex portion 66 provided on the manual feed tray 60, and is released from the second push switch 72 by the biasing means 75 provided on the conveyance guide 70. When the conveyance guide detection lever 54 and the manual feed tray detection lever 73 are separated from the second push switch 72, the second push switch 72 is turned off, and the open state of the conveyance guide 70 is detected.

FIG. 7 shows a state where the manual feed tray 60 is opened with respect to the duplex unit 50 from the state of FIG.
When the manual feed tray 60 is opened from the state of FIG. 6, the manual feed tray detection lever 73 is separated from the second push switch 72 and is also separated from the convex portion 66 provided on the manual feed tray 60. Yes. Therefore, the manual feed tray detection lever 73 does not contact the second push switch 72, and the open / close state of the manual feed tray 60 is not detected.

When the duplex unit 50 is in the open state, the duplex unit 50 is opened, so that the paper transport path (indicated by a thick line) from the manual sheet feeder is divided, and the manual feed tray 60 can be opened regardless of whether the manual feed tray 60 is open or closed. Cannot be fed. For this reason, the second push switch 72 does not need to detect the open / closed state of the manual feed tray 60 when the duplex unit 50 is open. That is, when the duplex unit 50 is in the open state, the second push switch 72 only needs to detect the open / closed state of the transport guide 70.
In the present embodiment, when the duplex unit 50 is in the open state and the conveyance guide 70 is in the open state, the manual feed tray detection lever 73 is in a position where it does not come into contact with the second push switch. As a result, the second push switch 72 can detect only the open / closed state of the transport guide 70.

  Further, as a detecting means for detecting the open / closed state of the manual feed tray 60 and the conveyance guide 70 in accordance with the open / close of the duplex unit 50, a transmissive or reflective optical sensor may be used. By using a transmissive or reflective optical sensor, the open / closed state of each of the manual feed tray 60 and the conveyance guide 70 can be detected without direct contact between the detection member and the detection means. For this reason, the installation possible range of a detection member and a detection means spreads, and the consumption and damage of the member by contact can be prevented.

What has been described above is merely an example, and the present invention has specific effects for each of the following modes.
(Aspect A)
A full-color printer comprising a duplex unit 50 that can be opened and closed on the apparatus main body 1, a conveyance guide 70 that is supported by the duplex unit 50 so as to be opened and closed, and a manual feed tray 60 that is supported by the outer portion of the duplex unit 50 so as to be opened and closed. In the open / close detection mechanism used for
A second push switch 72 for detecting the open / close state of each of the transport guide 70 and the manual feed tray 60, and a transport guide that is brought into contact with and separated from the second push switch 72 according to the opening / closing of the transport guide 70. A detection lever 54 and a manual feed tray detection lever 73 that is brought into and out of contact with the second push switch 72 according to opening and closing of the manual feed tray 60;
When the duplex unit 50 is in the closed state, the conveyance guide detection lever 54 is positioned so as not to contact the second push switch 72, and when the duplex unit 50 is in the open state, the manual tray detection is performed. The lever 73 is moved to a position where it does not come into contact with the second push switch 72.

By providing such a mechanism, as described in the above embodiment, the second push switch 72 detects only the open / close state of the manual feed tray 60 when the duplex unit 50 is closed, and the duplex unit 50 is detected. When is open, only the open / closed state of the transport guide 70 can be detected.
Therefore, there is an excellent effect that the opening / closing state of the conveyance guide 70 and the manual feed tray 60 provided inside the duplex unit 50 can be detected by one detection means, and the cost related to the opening / closing detection mechanism can be reduced.

(Aspect B)
In the open / close detection mechanism of (Aspect A), when the conveyance guide 70 is in the open state, the manual feed tray detection lever 73 is moved to a position where it does not contact the second push switch 72.
By providing such a mechanism, as described in the above embodiment, when the second push switch 72 is in the closed state of the duplex unit 50, only the open / close state of the manual feed tray 60 is detected, and the duplex unit 50 is detected. In the open state, only the open / closed state of the conveyance guide 70 can be detected.
Therefore, there is an excellent effect that the opening / closing state of the conveyance guide 70 and the manual feed tray 60 provided inside the duplex unit 50 can be detected by one detection means, and the cost related to the opening / closing detection mechanism can be reduced.

(Aspect C)
In the open / close detection mechanism of (Aspect A), a push-type switch that detects when the switch is pressed is used as the second push switch 72.
Thereby, the effect that the opening / closing state of the conveyance guide 70 and the manual feed tray 60 provided in the inside of the duplex unit 50 with an easy structure can be detected is obtained.

(Aspect D)
In the open / close detection mechanism of (Aspect A), an optical sensor is used as the second push switch 72.
Thereby, it is possible to detect the open / closed state of the conveyance guide 70 and the manual feed tray 60 provided inside the duplex unit 50 without the detection member and the detection means being in direct contact with each other. For this reason, the installation possible range of a detection member and a detection means spreads, and the consumption and damage of the member by contact can be prevented.

(Aspect E)
A sheet conveying device that can be opened and closed on the image forming apparatus main body; a conveyance guide that is supported by the sheet conveying device so as to be opened and closed; and a sheet stacking unit that is supported by the outer portion of the sheet conveying device so as to be opened and closed. The image forming apparatus includes any one of the opening / closing detection mechanisms described in (Aspect A) to (Aspect D).
Thus, the open / close state of the conveyance guide 70 and the manual feed tray 60 provided inside the duplex unit 50 can be detected by one detection means. Therefore, the cost related to the open / close detection mechanism can be reduced.

DESCRIPTION OF SYMBOLS 1 Apparatus main body 2 Photosensitive drum 3 Push switch 4 Convex-shaped part 10M, 10C, 10Y, 10Bk Image forming unit 11 Intermediate transfer belt 12 Primary transfer roller 13 Secondary transfer counter roller 14 Optical writing device 15 Paper feed cassette 16 Paper feed Means 17 Conveying roller pair 18 Registration roller pair 19 Secondary transfer roller 20 Fixing device 21 Switching claw 26, 27, 28 Conveying roller pair 26a, 27a, 28a Drive side roller 29 Discharge roller pair 30 Discharge tray 30a Discharge tray lower stage 30b Discharge tray upper stage 31 Discharge roller pair 40 Sensor 50 Duplex unit 51 Rotating shaft 52 Refeed path 53 Convex shaped portion 54 Conveying guide detection lever 55 Rotating shaft 56 Biasing means 60 Manual feed tray 61 Rotating shaft 62 Roller 63 Supply roller 64 Separation roller 65 Paper feed part 66 Convex part 70 Conveyance guide 71 times Moving shaft 72 Push switch 73 Manual tray detection lever 74 Rotating shaft 75 Biasing means

Claims (5)

An image forming apparatus comprising: a sheet conveying device that can be opened and closed on an image forming apparatus body; a conveyance guide that is supported by the sheet conveying device so as to be opened and closed; In the open / close detection mechanism used in the device,
Detection means for detecting the open / close state of each of the transport guide and the paper stacking means, a first detection member that is brought into contact with and separated from the detection means in response to opening / closing of the transport guide, and A second detection member that is brought into contact with and separated from the detection means in response to opening and closing, and when the paper transport device is in a closed state, the first detection member is brought into a position that does not contact the detection means, and An open / close detection mechanism characterized in that when the paper transport device is in an open state, the second detection member is positioned so as not to contact the detection means. In the opening / closing detection mechanism of claim 1,
An opening / closing detection mechanism characterized in that when the conveyance guide is in an open state, the second detection member is positioned so as not to contact the detection means. The opening / closing detection mechanism according to claim 1,
An opening / closing detection mechanism using a push-type switch that detects when the switch is pressed as the detection means. The opening / closing detection mechanism according to claim 1,
An open / close detection mechanism characterized in that an optical sensor is used as the detection means. An image forming apparatus comprising: a sheet conveying device that can be opened and closed on an image forming apparatus body; a conveyance guide that is supported by the sheet conveying device so as to be opened and closed; In the device
An image forming apparatus comprising the open / close detection mechanism according to claim 1.

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