JPH06258893A - Electrophotographic device - Google Patents

Abstract

PURPOSE:To eliminate paper winding with a less expensive and-a+ easy method. CONSTITUTION:A paper detecting device is constituted of a lever member 1 which is supported so that it can turn according to the presence or the absence of a paper and a sensor member 3 detecting the presence or the absence of the paper by being on/off by the turning of the member 1. The position of the member 1 is controlled by a sliding member 4 interlocking with the opening and closing of a cover member 15, so that the member 3 is turned on/off.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a paper presence detecting device for an electrophotographic device such as a laser beam printer or a copying machine.

[0002]

2. Description of the Related Art In a conventional laser beam printer as an electrophotographic apparatus, as shown in FIG.
The transfer sheet P fed and conveyed from the first sheet is inverted by 180 ° by the reversing roller 90, and is ejected by the sheet ejection rollers 76 and 80 through the transfer section 85, the conveyance guide 75, and the fixing device 70. An integrated electrical component board 74, in which an electrical component system such as a drive circuit is mounted on one substrate, is provided in a space sandwiched between a sheet feeding cassette 91 and a transport guide 75, and includes a motor (not shown), a fixing device 70, and an optical system. A compact, low-cost type configuration has been devised in which each unit such as 82 and the integrated electric component board 74 are automatically connected by a floating connector. This replaces the fixing device 70 with a conventional hollow pipe-shaped roller and a halogen heater, and replaces the flat ceramic heater 63 with the thermoplastic thin film 6 as shown in FIG.
It is possible to reduce the power supply capacity by using a power-saving type fixing system (hereinafter referred to as a surf fixing system) that presses the transfer paper through 1 to immediately fix the paper without warm-up time. It is also a factor for realizing the integrated electric component board 74.

A register sensor 87, which is composed of a photo interrupter and a lever member, detects the arrival of the leading edge of the paper in the vicinity of the upstream side of the transfer paper device 85, and a paper discharge similarly configured in the vicinity of the downstream of the fixing device 70 for detecting the discharge of the paper. It has a sensor 69 and uses these sensors 87 and 69 to scan the scanner 82.
The main body control CPU (not shown) performs laser writing on the drum 84, paper feed timing control, fixing sequence control, jam detection, and the like. An opening / closing cover 77 is provided on the downstream side of the fixing device 70 for jamming and maintenance, and a safety measure is taken by a door open sensor (made of a photo interrupter or a micro switch) for detecting opening / closing of the cover 77. ing.

[0004]

However, in the conventional example using the surf-fixing type fixing device 70, the accordion jam or the transfer paper J as shown in FIG. 6 is not separated from the film 62 or the pressure roller 65. When a wrapping jam that causes wrapping occurs, the main body control CPU detects the time from the paper feed timing to reach the paper discharge sensor 69 and stops the main body. However, if the user closes the opening / closing cover 88 without removing the jammed paper J after opening the opening / closing cover 88, the CPU resets the jammed state by a door switch (not shown) linked to the opening / closing cover 88. With the jammed paper J remaining inside, the pre-rotation is started in the forced paper discharge mode, and the jammed paper J is about to be further conveyed. This is especially true when the paper is wrapped around the fixing device 70, that is, when the jammed paper J exists between the registration sensor 87 that detects the leading edge of the paper and the paper discharge sensor 69, the CPU causes the jammed paper J to be stored in the main body. Is not detected, the jammed paper J is caught in the fixing device 70 and jamming becomes impossible, and the film 61 may be destroyed.

Therefore, a third paper presence / absence sensor is provided between the registration sensor 87 and the paper discharge sensor 69 as shown in part A of FIG. 7 to detect the presence / absence of residual paper even if the sheet is reset without jam clearance. Has proposed a structure that prevents the paper 61 from being forcibly discharged and prevents the film 61 from being damaged.

However, in the above-mentioned conventional example, in addition to the registration sensor 87, the paper discharge sensor 69, the plural door open sensors, the paper sensor in the cassette, and the like, a third paper presence sensor A is required, which is not inexpensive. Not only the number of photointerrupters increases, but also the number of ports of the CPU that takes in the output increases, which has been a problem in achieving significant downsizing and cost reduction.

The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to provide an electrophotographic apparatus capable of eliminating paper wrapping by an inexpensive and simple method. is there.

[0008]

In order to achieve the above object, the present invention has a paper detection device for detecting the presence or absence of paper on the downstream side of the transfer device and on the upstream side of the fixing device. In an electrophotographic apparatus having an openable / closable cover member that opens a paper transport path on the downstream side of the container, a lever member that is rotatably supported by the paper detection device depending on the presence or absence of paper, and a paper member that is rotated by the lever member. It is characterized in that it is constituted by a sensor member for detecting the presence / absence of ON / OFF, and further, the position of the lever member is regulated by a slide member interlocking with the opening / closing of the cover member so that the sensor member is turned ON / OFF.

An electronic device having a paper detection device for detecting the presence / absence of paper on the downstream side of the transfer device and the upstream side of the fixing device, and an openable / closable cover member for opening the paper conveyance path on the downstream side of the fixing device. In the photographic device, the paper detection device includes a horizontal reflection type light receiving and emitting element that detects the presence or absence of paper by reflecting and diffusing light depending on the presence or absence of paper, and further has a slide member that interlocks with the opening and closing of the cover member. A part of the slide member may have a hole for opening an upper portion of the horizontal reflective type light emitting / receiving element and a shutter portion for covering an upper portion of the horizontal reflective type light emitting / receiving element.

[0010]

According to the present invention, the sliding member interlocking with the opening / closing cover is provided with the rotatable residual paper detection lever disposed between the transfer unit and the fixing unit, so that the door can be opened / closed. Also, it becomes possible to obtain two types of information such as the presence or absence of residual paper with a single photo interrupter, and it is possible to solve the problem of paper wrapping by an inexpensive and simple method.

[0011]

1 to 3 are drawings showing the features of a laser beam printer as an electrophotographic apparatus according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a photo interrupter which rotates depending on the presence or absence of a transfer paper P. 3 is a residual paper detection lever for opening / blocking the optical axis 3a, 2 is a detection lever holding member for rotatably holding the residual paper detection lever 1 and positioning it with respect to the main body, 4 is a rear opening / closing during jam processing The spring member 33 is a slide member that slides in conjunction with the rotation of the cover 15.
Is always urged toward the rear opening / closing cover 15.
Reference numeral 6 denotes an integrated electrical board on which all electrical components such as a power supply, a CPU, a main body drive circuit, a high-voltage circuit, etc. are mounted, and is covered and electrically shielded by a transport guide made of sheet metal. Reference numeral 13 denotes a surf fixing device composed of a flat plate-shaped ceramic heater 8, a thermoplastic thin film 7, an elastic pressure roller 10 and the like, and a transfer device 25 and a scanner unit 19
Like the electric appliances-related parts such as the above, when they are assembled to the main body, they are automatically electrically connected to the integrated electric component board 6 by a floating connector (not shown).

Reference numeral 26 is a resist sensor for detecting the leading edge of the paper and for timing the laser writing on the drum 21 by the scanner unit 19 and detecting the residual paper at the time of start-up, which is configured with a photo interrupter (not shown). A paper discharge sensor 12 detects the arrival of the front end of the paper and the escape of the rear end of the paper, and detects the residual paper at the time of startup, and is composed of a photo interrupter (not shown) like the registration sensor 26.

Here, the driving force is transmitted to the one-rotation control clutch (not shown) by the input of the print start signal, the paper feed roller 27 makes one rotation, and the transfer papers P in the paper feed cassette 29 are fed one by one and inverted. It is sent to the carrying roller 28, and when the leading end reaches the registration sensor 26, laser writing on the drum 21 is performed. Then, the transfer sheet P has an image transferred by the transfer section 25 and is guided by the conveyance guide 5,
The unfixed toner is guided to the fixing device 13 and fixed on the transfer paper P. The transfer paper P that has come out of the fixing device 13 is a paper discharge sensor 12.
As a result, the arrival of the leading end is detected, and at the same time, the escape of the trailing end is also detected, so that the retention of the paper due to the jam at the exit of the fixing device 13 is detected. The transfer paper P that has passed the paper ejection sensor 12 is ejected to the tray 23 integrally provided on the outer cover 24 via the first paper ejection roller 14, the paper guide portion 16, and the second paper ejection roller 18.

However, if the leading edge of the transfer paper does not reach the paper discharge sensor 12 and is wound around the fixing film 7 for some reason, as shown in FIG.
U judges from the time when it should reach the paper ejection sensor 12 from the paper feed timing, detects it as a winding jam, and stops the main body. At this time, the distance between the fixing nip portion N and the discharge sensor 12 is E, the outer peripheral length of the fixing film 7 is πD,
Assuming that the circumference length from the leading end of the wound transfer paper J to the fixing nip portion is A, a winding jam is surely detected, and the transfer paper J is prevented from being wound around the fixing film 7 more than once, thereby facilitating the jam processing. Therefore, the relationship between A, πD, and E is expressed by the following mathematical formula 1,

[0015]

## EQU1 ## Arranged so that πD> A> E, and sequence-controlled.

As shown in FIG. 3, in order to reliably detect the residual paper in the state where the winding jam occurs, the residual paper is detected at a position where the minimum size of plain paper (A5 size) generally used can also be detected. The lever 1 is provided on the conveyance guide 5 by the holding member 2. Specifically, if the length in the A5 size vertical direction is L, the distance from the fixing nip portion N to the residual paper detection lever 1 is B, and the distance from the fixing nip portion N to the rear end of the A5 size paper is C, Formula 2 below,

[0017]

## EQU2 ## The residual paper detection lever 1 is provided at a position such that LA = C> B.

The residual paper detection lever 1 is shown in FIG.
As shown in (d), the lever portion 1a that contacts the transfer paper J
And a first shutter portion 1c, a second shutter portion 1e, and an optical axis 3a that shield the optical axis 3a of the photo interrupter 3.
2d has a slit portion 1d for opening the center of gravity so that it is balanced by its own weight in a state as shown in FIG. 2 (c), and is freely rotatable from the position shown in FIG. 2 (b) to (c). is there.

The slide member 4 is constantly urged to the left by the spring 33, and when the rear opening / closing cover 15 is opened, the stopper portion 4b of the slide member 4 contacts the inner surface of the conveyance guide 5 (see FIG. 2). It is urged to (c), (d)). At the same time, the lever regulating surface 4a of the slide member 4
Is separated from the detection lever 1, the detection lever 1 becomes free. When the back opening / closing cover 15 is closed, the flat plate portion 4c of the slide member 4 is restricted by the restriction ribs 15b of the back opening / closing cover 15, so that the slide member 4 resists the spring force of the spring 33, as shown in FIG. ) Or (b). At this time, the lever regulating surface 4a of the slide member 4 and the rear end portion 1f of the detection lever 1 come into contact with each other, and the lever regulating surface 4a serves as a stopper, so that the detection lever member 1 is balanced by its own weight (FIG. 2 (c)). Is restricted to a substantially upright state (FIG. 2 (a)).

The functions of the rear opening / closing cover 15 in the open / closed state and the presence / absence of residual paper will be described below. (A) Rear open / close cover 15: closed, no residual paper In such a case, as shown in FIG. 2 (a), the detection lever 1 is regulated by the slide member 4 to be in a substantially upright state and the slit portion 1d. And photo interrupter optical axis 3a
Since they match, the CPU determines that the main body is normal from the output. (B) Rear open / close cover 15: closed, residual paper present In such a case, as shown in FIG.
As a result, the detection lever 1 is tilted and the first shutter portion 1c blocks the optical axis 3a of the photo interrupter, so the CPU determines from the output that the main body is abnormal (there is residual paper), and even if the power supply is reset once. Also does not rotate the front. (C) Rear open / close cover 15: open state, no residual paper In such a case, as shown in FIG. 2 (c), the slide member 4 is moved leftward by the spring 33, and the lever regulating surface 4a is moved.
Is also separated from the detection lever rear end 1f, the detection lever 1
Becomes free and is balanced by its own weight in the state shown in FIG. 2 (c). At this time, the second shutter unit 1e blocks the photo interrupter optical axis 3a, so that the output from the CPU
Judges that the main body is abnormal (opening the rear cover), and does not rotate the front even if the power is reset. (D) Rear open / close cover 15: open state, with residual paper In such a case, as shown in FIG. 2D, the detection lever 1 is tilted by the residual paper J even if the slide member 4 is separated leftward. Since the first shutter portion 1c blocks the photo interrupter optical axis 3a, the abnormality is detected as in the above (b).

The output of the photo interrupter 3 is taken into the CPU during normal paper feeding and counted in the same manner as the paper discharge sensor to detect the arrival of the leading edge of the paper and the escape of the trailing edge to detect a jam or adjust the fixing temperature. It may be used for sequence control, or may be a system in which the CPU reads only immediately before starting the main body and performing pre-rotation. Although the photo interrupter 3 is used here, a micro switch or a leaf spring contact type switch may be used.

FIG. 4 shows a second embodiment of the present invention.

In the figure, the basic structure is the same as that of the first embodiment, and the units and parts common to the first embodiment are designated by the same reference numerals. In the figure, 43 is a light emitting unit 43.
In the reflection type photo interrupter having a and the light receiving portion 43b, as shown in FIG. 4A, in the state where the rear opening / closing cover 15 is closed and there is no residual paper J, the hole 41a provided in the slide member 41 and the transport guide 42 are provided. Hole 42 provided in
Residual paper J that b matches and blocks the holes 41a and 42b of both
Therefore, the diode light emitted from the light emitting portion 43a only passes through the holes 41a and 42b of the both and does not reflect anywhere and does not reach the light receiving portion 43b. Therefore, the CPU determines that the main body is normal. On the other hand, when the rear opening / closing cover 15 is closed and the residual paper J is present as shown in FIG. 4B, the diode light passing through the holes 41a and 42b of the slide member 41 and the transport guide 42 is reflected on the rear surface of the residual paper J. Then, since it reaches the light receiving portion 43b, the CPU determines that the main body is abnormal (there is residual paper J). On the other hand, when the back opening / closing cover 15 is closed, the spring 33 causes the slide member 41 to move.
Is urged to a position where the stopper 41b comes into contact with the conveyance guide 42, and accordingly, the through hole 41a opened above the photocoupler 43 also moves to the left, and the shutter portion 41d.
Covers the upper surface of the photocoupler, whereby the diode light from the light emitting portion 43a is reflected by this surface 41d and reaches the light receiving portion 43b, and the main body CPU determines that it is abnormal. When the rear opening / closing cover 15 is open, the shutter portion 41d covers the photocoupler regardless of the presence or absence of the residual paper J, so the state does not change, but there is no problem from the viewpoint of abnormality detection.

FIG. 5 shows a third embodiment of the present invention. Although the basic configuration is the same as that of the first embodiment, the residual paper detection lever 53, which is biased by a weak spring (not shown) in the clockwise direction in the figure, is cut at the edge of the paper. The position of 53 is forcedly rotated by a pin 51a of a slide member 51 which is interlocked with a rear opening / closing cover (not shown), and the movement of the rear opening / closing cover is converted into ON / OFF of the photo interrupter.

[0025]

As described above, the slide member interlocking with the rear opening / closing cover for jamming the vicinity of the fixing device is provided, and the residual paper detection lever which tends to fall down by its own weight is abutted on the slide member for positioning. By configuring the residual paper detection lever to change the output of the photo interrupter according to the open / closed state of the rear opening / closing cover or the presence / absence of residual paper, two information such as the open / closed state of the door and the presence / absence of residual paper can be obtained by one photo interrupter. It is possible to reduce the number of parts, the number of CPU input ports, etc., and it is possible to solve various problems due to winding with an inexpensive and simple method.

[Brief description of drawings]

FIG. 1 is a main sectional view of a laser beam printer as an electrophotographic apparatus according to an embodiment of the present invention.

FIG. 2 is a functional explanatory diagram depending on the opened / closed state of the open / close cover and the presence / absence of residual paper. FIG. 2 (a) shows the closed state of the open / close cover and no residual paper. ) Indicates that the open / close cover is closed and there is residual paper.
FIG. 7C shows the open / close cover in the open state with no residual paper, and FIG. 6D shows the open / close cover in the open state with residual paper.

FIG. 3 is an arrangement condition diagram of each sensor of FIG.

FIG. 4 is a functional explanatory view of a laser beam printer as an electrophotographic apparatus according to a second embodiment of the present invention. FIG. 4A shows a state in which an open / close cover is closed and there is no residual paper. The same figure (b) shows the state where the open / close cover is closed and there is residual paper, and the same figure (c) shows the state where the open / close cover is open and there is no residual paper. d) shows a state in which the open / close cover is open and there is residual paper.

FIG. 5 is a functional explanatory diagram of a laser beam printer as an electrophotographic apparatus according to a third embodiment of the present invention.

FIG. 6 is an explanatory diagram of a surf fixing device and a winding jam state.

FIG. 7 is a main sectional view of a laser beam printer as a conventional electrophotographic apparatus.

[Explanation of symbols]

 1 Residual Paper Detection Lever Member 2 Residual Paper Detection Lever Holding Member 3 Photointerrupter 4 Slide Member 5 Conveying Guide 6 Integrated Electrical Board 12 Paper Ejection Sensor Lever 13 Surf Fixing Device 14 First Paper Ejection Roller 15 Rear Open / Close Cover 18 Second Ejection Paper roller 19 Scanner unit 21 Photosensitive drum 25 Transfer roller 26 Registration sensor

Claims (2)

[Claims] 1. An electronic device having a paper detection device for detecting the presence / absence of paper on the downstream side of the transfer device and on the upstream side of the fixing device, and further having an openable / closable cover member for opening a paper conveyance path on the downstream side of the fixing device. In a photographic device, a lever member rotatably supported by the paper detection device depending on the presence / absence of paper and the presence / absence of paper are detected by the rotation of the lever member.
The position of the lever member is regulated by a slide member which is constituted by a sensor member for N / OFF detection, and which is interlocked with the opening and closing of the cover member to turn the sensor member ON / OFF.
An electrophotographic device which is turned off. 2. An electronic device having a paper detection device for detecting the presence / absence of paper on the downstream side of the transfer device and on the upstream side of the fixing device, and further having an openable / closable cover member for opening a paper conveyance path on the downstream side of the fixing device. In the photographic device, the paper detection device includes a horizontal reflection type light emitting / receiving element that detects the presence or absence of paper by reflecting and diffusing light depending on the presence or absence of paper, and further has a slide member that interlocks with the opening and closing of the cover member. An electrophotographic apparatus comprising: a hole for opening an upper portion of the horizontal reflective type light emitting / receiving element and a shutter portion covering an upper portion of the horizontal reflective type light receiving / emitting element in a part of the slide member.