JPS6181347A - Paper feeder - Google Patents

Abstract

PURPOSE:To enhance the accuracy of defecting the state of an image target supporter without requiring so much space, furthermore to enable the final state of the image target supporter to be detected by installing reflection type optical sensors inside a cabinet and in the space between the cabinet and separation rollers respectively. CONSTITUTION:When a plate 34 is lifted by an elevator arm 33a and a sheet 36 touches a roller 37 as a copy work starts and proceeds, the sheet is taken out toward separation rollers 38a, 38b, thereby the second paper sheet and the subsequent are fed back into a cabinet 32 by the roller 38b and the sheet on the top position is conveyed to a sensitive drum by the roller 38a. During this period, photo-transistors 40b, 41b of a miniature type infra-red reflection optical sensing unit receive the light reflected from the sheet 36 to have circuits 57 and 58 rendered L level and a circuit 56 enters the information of presence of sheet 36 inside the cabinet 32 into a control unit 54. After completion of the process of copy, when each unit is stopped in its operation, the arm 33a turns to move in the opposite direction, the plate 34 also gets stationary on the bottom of cabinet and thus all of the sheets inside the cabinet are delivered away, the circuit 57 is set to high impedance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a paper feeding device for feeding sheets of paper one by one in a paper feeding cassette device in an electrophotographic apparatus or the like.

[Technical background of the invention and its problems]

2. Description of the Related Art Conventionally, in an electrophotographic apparatus or the like, which feeds sheets of paper from a paper feed cassette device, a device is used in which separating claws are provided at the front ends of both sides of a housing in order to take out the sheets one by one. However, this device has a problem in that when taking out a sheet of paper, the separating claw causes the front end of the sheet to curl, making it easy for paper jams to occur in the conveyance path. For this reason, a device as shown in FIG. 5, in which the casing is not provided with separation claws, is also used.

In other words, this device takes out one or more sheets of paper (12) from an elevator (111) through an ejection port □-ra 6:1, and then separates the sheets by a separation roller (14). It feeds paper Oz one by one.And in such a device, the first one detects the presence or absence of sheet paper A2 in the paper feeding cassette (un).
As a detection device, one shown in FIG. 6 is used. In this device, when the lever 07 is pressed down by attaching the paper feeding force cera) (161), the board (a) moves around the shaft 08 against the spring (18a) as shown by the dotted line in Fig. 6(a). The board is rotated in the direction of the arrow S to the position, and the first stopper (2υ) and the second stopper (2) on the board (2) are separated from the actuating part (c) and the first arm (26a) of the microswitch I24, respectively. , the operating part (c) is connected to the shaft (23
Detection unit (5) placed on sheet paper az centering on a)
At the same time, the arm (A) is returned in the direction of the arrow and the microswitch (2) is turned on. Then, paper feeding is performed in this state, and when the plate 0υ is gradually rotated in the direction of arrow U and all the sheets 02 are fed,
The detection part (5) is dropped into the through hole (lla) of the play) (Ill), and the actuating part Q is rotated in the direction of arrow V, so that the pin (23b) comes into contact with the second arm (26b). , the arm is rotated in the direction opposite to the direction of the arrow, the microswitch is turned off, and it is detected that there is no paper sheet H.

However, such a mechanical device requires space, and has the drawback that miniaturization of the device is hindered, especially in a device in which multiple paper feed cassette devices are installed.

For this reason, an optical second detection device is also used to save space as shown in FIG. This device is plate 0
A light source (c) and a detection circuit (30a) are placed between the through holes of υ.
A CdS cell (to) connected to the sheet paper (12
Cd8 cell (to) when all paper remains and when all paper is fed
The presence or absence of the sheet paper (13) is detected by comparing the resistance values of the sheets.

However, although this device saves space, the light-receiving elements such as CdS cells (2) and phototransistors are easily affected by ambient light other than the light source (3), reducing detection accuracy. The drawback is that it is difficult to adjust the sensitivity of the light-receiving element and to set the distance between the light source and the light-receiving element.

[Purpose of the invention]

The present invention has been made based on the above circumstances, and an object of the present invention is to provide a paper feeding device that can detect the presence or absence of an image support with high accuracy without requiring a large space.

[Summary of the invention]

In order to achieve the above object, the present invention provides a reflection type photodetection device that detects the image support within the housing, and a reflection type photodetection device that detects the image support between the housing and the separation roller. As a result, the accuracy of detecting the presence or absence of an image support can be increased without taking up space, and the presence or absence of the image support can be detected up to the final image support.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3. At the bottom of the 0 side of the casing, there is an elevator arm (3
A plate 04 is provided which is pivotable by the free end of 3a). C34) A feed roller C(7) is provided at the upper front end for taking out the sheet paper (goods) serving as an image support from the housing G2, and a feed roller C(7) is provided at a position adjacent to the housing 02. - Separation rollers (38J1) and (38b) are provided for feeding sheets of paper one by one by OD.

Further, an infrared light emitting diode (40a) and an infrared transmitting filter are attached to the free end of the elevator arm (33M) so as to illuminate the through hole (34a) of (41) <34). (40b)
A first infrared reflection type photodetection device consisting of 0υ
are separation rollers (38a) and (38b) from the housing 63.
A second infrared reflection type photodetection device having the same structure as the first infrared reflection type photodetection device (41) is attached to G13 so as to illuminate the conveyance path OI of the sheet paper (to). In addition, (4'3 to 9) are resistors 1 to 11 of the detection circuit connected to the control device 64 that controls the main body (not shown).Furthermore, 6η is a phototransistor ( This is the first voltage comparator circuit to which the voltage from the phototransistor (40b) is input and the reference voltage (+Vcc) is input to the non-inverting input terminal.
b) receives the reflected light from the sheet paper (to) by the infrared light emitting diode (40a), and when the inverting input terminal voltage>the non-inverting input terminal voltage, its output becomes 1L# level, while the sheet paper ( When all sheets (to) are fed and there is no light reflected by the sheet paper (g) and the inverting input terminal voltage is the non-inverting input terminal voltage, the impedance becomes high.

On the other hand, the transistor (41b) is connected to the inverting input terminal.
The voltage from + is input to the non-inverting input terminal.
Vcc) is input to the second voltage comparator circuit, and the first
voltage comparison circuit 6? ), the phototransistor (41b) receives the reflected light from the sheet paper (to) by the infrared diode (41m), and when the inverting input terminal voltage > the non-inverting input terminal voltage, the output becomes 1L'' level, When there is no light reflected by the paper and the inverting input terminal voltage is the non-inverting input terminal voltage, the impedance is high.In other words, the outputs of the first and second voltage comparison circuits 67) and (to) are both 1L.
〃When the level is reached, the output of the detection circuit is O [■],
Input to the control device 64) that there is a sheet of paper (to).

Also, when either one of the outputs of the first and second voltage comparison circuits 6η, 68 is at the 1L# level and the other is at high impedance, the output of the detection circuit (to) is set to 0 [■],
Input the fact that sheet paper (to) is available to the control device.

When the outputs of the first and second voltage comparator circuits 67) and (67) are both high impedance, the output of the detection circuit (a) is pulled up by the resistor 11 and becomes the 1H level, and becomes +Vcc (V). and control equipment fit, C54
) Enter that there is no sheet of paper (G). The main body (not shown) is a housing 63 for storing sheet paper.
When the phototransistor (40b) receives the reflected light from the sheet paper (g), the output of the first voltage comparator circuit f17) becomes 1L'' level, and the detection circuit (a) is connected to the control device e54. ), the controller 54) displays on the control panel of the main unit (not shown) that it is ready for copying.Then, when copying is started, the elevator system and When the plate is pushed up by the elevator arm (33a) which rotates in the direction of the arrow W when the low:in is driven, and the sheet paper (to) comes into contact with the feed roller 071, one or more sheets The paper (to) is separated by the separation roller (3B).

It is scattered to the (38b) side. Thereafter, the second and subsequent sheets are returned to the housing 03 by the lower paper separation roller (38b) which is rotated in the direction of arrow X, while the upper part 11II0-ra ( 38m), only the top sheet of paper is fed toward the photoreceptor drum (not shown). During this time, the first and second infrared reflection type photodetectors 0I and 0υ each have a phototransistor (4ob).
, (4th) receives the reflected light from the sheet paper (to), so the first and second voltage comparison circuits 67).

The outputs of - are both at tL" level 1, and the detection circuit - inputs to the control device cia that there is a sheet of paper (G) in the vicinity of the casing CI. After this, when the copying process is finished, each device stops. At the same time, the elevator arm (33a) is rotated in the direction opposite to the direction of arrow W, and the plate (goods) is also stopped at the bottom of the casing C13.While repeating this operation, the casing C
When all the paper sheets in Ik are fed, no reflected light from the paper sheets enters the phototransistor (40b), and the output of the first voltage comparator circuit 6η becomes high impedance. However, at this time, although disturbance light enters through the through hole (341), it is cut by the infrared transmission filter, and the phototransistor (40b) does not detect the light. On the other hand, at this time, in the second voltage comparator circuit, the separation roller (38a) is removed from the housing c13.

If the last sheet of paper is deposited at (38b), the 1L# level will be output until all of these sheets are fed toward the photoreceptor drum (not shown). The detection circuit inputs to the control device 64) that there are still sheets of paper. And separation rollers (33a), (3
8b), when all the sheets of paper have been fed, the second voltage comparison circuit an and the first voltage comparison circuit group are set to high impedance, and the detection circuit (a) detects that the sheet paper is fed to the control device 541. Input that all paper has been fed and is no longer being fed.This will cause the main unit's control panel (-not shown)
A message indicating that there is no sheet paper is displayed, and the operator must replenish the housing 02 with sheet paper (A).

With this configuration, the presence or absence of sheet paper OD can be easily detected by simply installing a small infrared reflection type photodetector ft, (41, G11l) near the housing O2, and its installation is easier than with conventional devices. In addition to significantly saving space, the infrared reflection type photodetector is not adversely affected by ambient light due to the infrared transmission filter, improving detection accuracy and making it easier to adjust the sensitivity of the photodetector like conventional optical devices. There is no need to set the distance between the light source and the light receiving element, etc.
High precision is not required during manufacturing, and the manufacturing process is simplified.

Note that this invention is not limited to the above-mentioned embodiments, and can be modified in various ways. For example, the mounting position of the reflection type photodetector is not limited, and only when the plate is stopped at the bottom of the housing, the sheet paper inside the housing is removed. If the structure is such that it detects the The device may be fixedly installed, or it may be installed above the housing as long as it does not interfere with sheet paper removal. Also, the detection circuit is completely arbitrary, and A-D
The output from the reflective photodetecting device may be inputted to the control device using a converter, or furthermore, the output from the reflection type photodetecting device may be directly inputted to a microcomputer in the control device. Further, the frequency of the light beam of the reflective photodetector is not limited either, and the light receiving element may use an optical filter depending on the type of light source.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to easily and reliably detect the presence or absence of an image support simply by installing a small reflective light detection device near the housing, which is not adversely affected by ambient light. Therefore, the space for installing the detection means can be saved compared to the conventional method, and the image forming apparatus itself can be made more compact, the detection accuracy is improved, and the time required for adjusting the sensitivity of the light-receiving element during manufacturing can be reduced. This also makes it possible to speed up the production line. Furthermore, if a reflection type photodetector is provided near the separation roller as in the embodiment, the image support can be detected until the final image support is fed to the photosensitive drum, and the image support can be detected. It is possible to detect more accurate replenishment timing.

[Brief explanation of drawings]

1 to 3 show one embodiment of the present invention, FIG. 1 is a partially omitted cross-sectional view, and FIG. 2 shows the state in which the first and second infrared reflection type photodetecting devices are attached. FIG. 3 is a partially omitted perspective view, FIG. 3 is a detection circuit thereof, FIG. 4 is a partially omitted cross-sectional view of another modification of the present invention, and FIGS. 6(a) is a front view showing the first detection device, FIG. 6(b) is a left side view showing the first detection device, and FIG. 7 is an explanatory diagram of the paper feeding mechanism. The second
FIG. 2 is a partially omitted sectional view showing the device of FIG. 32...TR body, 33...Elevator arm, 34
...Plate, 36...Sheet paper, 37...Feeding roller, 38! , 38b... separation roller, 4
0... First infrared reflective photodetector, 41... Second infrared reflective photodetector, 42... Bracket,
54... Control device, 56... Detection circuit,

Claims (1)

[Claims] 1. An image support on a plate provided at the bottom of the casing,
The feeder feeds sheets one by one by a separating means after being taken out from the housing, characterized in that at least a reflective light detection device for detecting the presence or absence of the image support is provided inside the housing. paper equipment. 2. A through-hole is formed in the plate, and a reflective photodetector is provided near the through-hole to detect the presence or absence of an image support in the through-hole. Paper feed device. 3. A through hole is formed in the plate, and a reflective photodetection device is provided near the through hole to detect the presence or absence of an image support in the through hole, and the image is detected in the conveyance path from the casing to the separating means. 2. A paper feeding device according to claim 1, wherein said paper feeding device is provided near said separation means to detect the presence or absence of a support.