JP2677673B2 - Paper detection mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Field of Industrial Application) [0001] The present invention relates to a paper-out detection mechanism for detecting when paper in a cassette is exhausted. The present invention relates to a paper out detection mechanism that has an empty switch that abuts against the paper and detects the presence or absence of paper in the cassette.

(Prior Art) Usually, in a desk-top copying machine or the like, a method is adopted in which a cassette accommodating a frequently used size of paper is attached to a paper feed unit. Further, a paper out detection mechanism for detecting that the paper in the cassette is exhausted is incorporated, and when the paper is exhausted, this is displayed on the display unit to inform the operator.

Conventionally, as this type of paper non-existence detecting mechanism, there is a mechanism in which an empty switch is fixedly arranged so that the actuator can contact the paper in the cassette. In this case, the cassette is inserted / removed along the moving direction of the actuator by utilizing the displacement of the actuator.

(Problems to be Solved by the Invention) However, the actuator of the empty switch has no problem if the mounting position of the cassette is always at a fixed position, but the mounting position of the cassette is not always fixed and the actuator does not move in the insertion / removal direction. There is a problem in that there is an error, which causes a decrease in the accuracy of paper detection.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a paper-out detection mechanism that can always detect paper-out accurately when the cassette mounting position is displaced in the cassette insertion / removal direction. Is what you are trying to do.

[Configuration of the Invention] (Means for Solving the Problems) In order to achieve the above object, the paper detection mechanism of the present invention has a first position inside the apparatus main body and a second position outside the apparatus main body. A sheet feeding cassette movable between the sheet feeding cassette, a detection unit for detecting the presence or absence of a sheet placed in the sheet feeding cassette when the sheet feeding cassette is at the first position, and the sheet feeding cassette. When moving between the first position and the second position, between the third position and the first position, which are separated from the first position by a predetermined distance toward the second position. The detection means is held at the fourth position when the cassette is located, and the detection means is held at the fourth position when the cassette is located between the third position and the second position. Holding means for holding at a fifth position spaced from the fourth position. And butterflies.

(Effect) That is, according to the present invention, the empty switch is automatically set to the non-cassette insertion / removal path when the cassette is not mounted, whereby the moving direction of the actuator of the empty switch and the insertion / removal direction of the cassette are substantially orthogonal to each other. Even if it does, the cassette can be surely inserted and removed. Since the empty switch is moved to the detection position by the moving means before the cassette mounting position is reached, good paperless accuracy can be maintained regardless of a slight deviation.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 2 shows the internal structure of the entire apparatus, and FIG. 3 shows the state in which the original cover is opened. Inside the apparatus main body 1, charging, exposure, development, transfer, peeling, cleaning, charge removal, fixing, etc. The image forming process constituting means 2 is built in, and an original placing table (hereinafter referred to as a platen glass) 3 on which an original D is set is provided on the upper surface.

Further, a platen glass 3 is provided on the rear edge of the apparatus main body 1.
A document pressing cover 4 for pressing the document D set thereon is attached, and a copy key 5, a clear / stop key 6, a numeric keypad 7, a display unit 8 and the like are arranged on a front edge of the upper surface of the apparatus main body 1. Operation panel 9 is arranged.

Further, the cover 10 that can be opened and closed is provided on the front surface of the apparatus main body 1, and a paper feed cassette accommodating paper P such as plain paper supplied to the image forming process constituting means 2 is provided on the lower front surface. (Hereafter, simply referred to as cassette) 11
Is installed. Further, on the left side of the apparatus main body 1, a tray 12 for accumulating the fixed paper P and a power switch 13 are provided.

The image forming process configuration unit 2 has the following configuration. That is, a drum-shaped photoconductor 20 as an image carrier is arranged at a substantially central portion in the apparatus main body 1,
Around the photoconductor 20, along the rotation direction thereof, the charging device 21, the exposure unit 20a of the exposure device 22, the developing device 23, the pre-electrification removing device 24, the transfer device 25, the developing device 26, the cleaning device 27. , Static eliminator 28
Etc. are sequentially arranged. Since these configurations are not directly related to the present invention, detailed description will be omitted.

Further, in the main body 1 of the apparatus, the paper P automatically fed from the cassette 11 or the paper P manually fed through the manual paper feed tray 29 is transferred to the photoconductor 20 and the transfer device.
A sheet conveyance path 31 is formed which leads to the tray 12 provided on the left side of the apparatus main body 1 via an image transfer section 30 between the sheet transfer section 25 and the sheet transfer section 25.

A registration roller pair 32 is disposed on the upstream side of the image transfer section 30 of the paper transport path 31, and a fixing device 33 and a paper discharge roller pair 34 are disposed on the downstream side. The peeling device 26
A conveyance belt unit 35 is disposed between the fixing belt 33 and the fixing device 33.

In addition, one sheet of paper P is placed near the mounted portion of the cassette 11.
A sheet feeding roller 36 for picking up the sheets one by one and a pair of conveying rollers 37 for receiving the sheets P picked up through the sheet feeding roller 36 and feeding them into a first branch conveying path forming the upstream side of the sheet conveying path 31. Each is rotatably arranged. Further, a manual feed roller 38 is arranged at the confluence of the first branch conveyance path and the second manual conveyance path.

Further, the apparatus main body 1 is in a state in which the upper unit 1A and the lower unit 1B are divided into two parts with the sheet conveying path 31 as a boundary, and a support shaft 40 provided on the paper feeding side is provided as necessary. The upper unit 1A can be opened about 25 degrees by using as a fulcrum. The support shaft 40 is configured by a shaft portion of a torsion bar that constantly urges the upper unit 1A in the opening direction.

In FIG. 2, reference numeral 41 denotes a cooling fan disposed above the fixing device, and reference numeral 42 denotes a manual feed guide for guiding paper to be manually fed. Reference numeral 43 denotes a high-voltage transformer, and reference numeral 44 denotes a scale serving as a reference for setting the document D.

FIG. 4 shows the sheet feeding device 50, which is a cassette.
11 and a paper feed roller 3 for feeding the paper P in the cassette 11
It has a structure including 6,36. The cassette 11 is
The sheet P is accommodated in a state where both corners in the take-out direction are pressed by the separating claws 51, 51, and both ends of the sheet P are moved by the movable guide members 52, 52 to which the separating claws 51, 51 are connected. The rear end is supported by a replaceable rear end support plate 53. Further, on the lower surface of the paper P in the take-out direction, there are provided push-up springs 54, 54 and a receiving plate 56 that is constantly lifted by a weaker push-up spring 55 so that the uppermost paper P is always in a position suitable for take-out. Has been pushed up.

Further, as shown in FIGS. 2 and 5, the paper feed rollers 36, 36 are rotatably supported by an arcuate delivery body 36a which comes into contact with the paper P and delivers the paper P. The arcuate delivery body 36a has a half-moon shape having an escape portion 36b that is a flat notch that does not contact the paper P. Further, the escape portion 36b is positioned on the lower surface when stopped, and the cassette 11 is taken out of the cassette 11 without lifting the paper feed roller 36 (direction of arrow A in FIG. 4).
It can be sent in the direction orthogonal to (direction of arrow B in FIG. 4).

In addition, as shown in FIG.
An empty switch 59 in which an actuator 58 composed of a link portion 58a and a tip portion 58b is brought into contact with the paper P in the cassette 11
Is provided, and a paper out detection mechanism 60 for detecting that the paper P in the cassette 11 is exhausted is provided. The empty switch 59 is a magnet type switch. Then, when the paper P is exhausted, the tip 58b of the actuator 58 falls into the hole 61 formed in the receiving plate 56, and the empty switch 59 is turned on. Then, the fact that there is no paper is displayed on the display unit 8 of the operation panel 9 and the apparatus is stopped.

Further, the empty switch 59 can be displaced in association with the insertion / removal operation of the cassette 11 by the switch moving means 62, and the empty switch 59 is automatically set to the non-cassette insertion / removal path when the cassette is not installed. It is configured to.

That is, as shown in FIG.
59 is attached to the free end side of an arm 64 that is rotatable about a shaft 63. The arm 64 is connected to the other end of a tension spring 66, one end of which is connected to the bracket 65 side, and is also attached to the sub arm 70 that is rotatable about the shaft 63 as a fulcrum.
In the state shown in FIG. 1, the empty switch 59 attached to the free end side is in contact with the cassette moving path 67.
It has become a state of being evacuated from. At this time,
A protrusion 68 provided in the vicinity of the pivotal support portion of the sub arm 70 comes into contact with the lower surface of the bracket 65 to regulate the rotation. In addition, the pressing piece 70a is attached to the pivot end of the sub arm 70 in a substantially vertical state.
When the cassette 11 is pushed to a certain extent, the pin 69 projecting on the cassette 11 pushes the pressing piece 70a to rotate the sub arm 70 against the urging force of the tension spring 66. It is dynamically displaced and moves to the position shown by the chain double-dashed line in FIG. At this time, the arm 64 moves to the position shown by the chain double-dashed line in FIG. 1 by the action of the tension spring 71 connecting the arm 64 and the sub-arm 7, so that the empty switch 59 is shown by the chain double-dashed line in FIG. It is designed to go down to the detection position.

Then, the actuator 58 of the empty switch 59 is brought into contact with the paper P, and the paper out detection state is set.

Push the cassette 11 to the specified position and
By the pin 69 protruding from the 11, the pressing piece 70 of the sub arm 70
When a is pushed, the sub arm 70 is rotationally displaced against the urging force of the tension spring 66, and moves to the position shown by the one-dot chain line in FIG. At this time, the arm 64 is urged downward in FIG. 1 by the tensile force of the tension spring 71 connecting the arm 64 and the sub arm 70, but the protrusion 72 of the arm 64 is the protrusion 73 of the main body of the image forming apparatus.
The rotation of the empty switch 59
Does not move from the detection position indicated by the chain double-dashed line in FIG.

When the cassette 11 is not attached, the pressing piece 70
Since a is not pushed by the pin 69 of the cassette 11, the sub arm 7
0 is rotationally displaced upward by the urging force of the tension spring 66.
At this time, since the arm 64 is in contact with the sub arm 70 at the surface 74, the arm 64 is also pivotally displaced upward by the pivotal displacement of the sub boom 70 upward, so that the empty switch 59 moves to the first position.
It is in a state of being lifted to the retracted position shown by the solid line in the figure.

The contact between the actuator 58 of the empty switch 59 and the cassette 11 is avoided, and the cassette 11 can be reliably inserted and removed and the empty switch 59 can be prevented from being damaged.

Further, the empty switch 59 is in a state in which the moving direction of the actuator 58 (the direction of arrow C in FIG. 5) is along the take-out direction of the paper P, and when the paper P is taken out, no excessive force is applied to the actuator 58, It is possible to maintain stable detection operation over a long period of time.

The present invention is not limited to the above-mentioned embodiment, but may be any one as long as the set position of the empty switch can be set to the cassette insertion / removal path and the non-cassette insertion / removal path by inserting / removing the cassette. The same effect can be obtained by application.

[Effects of the Invention] Since the present invention is configured as described above, the empty switch is automatically set to the position out of the cassette insertion / ejection path when the cassette is not installed, and the actuator of the empty switch moves accordingly. The direction and the insertion / removal direction of the cassette are substantially orthogonal to each other. Even in the case, the cassette can be surely inserted and removed. Further, even when the cassette mounting position in the cassette mounting state is deviated in the cassette insertion / removal direction due to interference, the empty switch is set in a state where it can be detected at a predetermined detection position, so that it is possible to always achieve accurate paper out detection. is there.

[Brief description of the drawings]

The drawings show a position embodiment of the present invention. FIG. 1 is a schematic configuration diagram of a paper-out detection mechanism, FIG. 2 is a schematic vertical sectional front view of an image forming apparatus, and FIG. FIG. 4 is a schematic perspective view showing the outer appearance of the image forming apparatus in an opened state, FIG. 4 is a schematic plan view of the sheet feeding device, and FIG. 11: Paper feed cassette (cassette), 58: Actuator, 59: Empty switch, 60: No paper detection mechanism, 62: Switch moving means, 67: Cassette moving path,
P: Paper.

Claims (2)

(57) [Claims] 1. A paper feed cassette movable between a first position inside the apparatus main body and a second position outside the apparatus main body, and when the paper feed cassette is at the first position Detection means for detecting the presence / absence of a sheet placed in a paper feed cassette; and a means for moving the paper feed cassette between the first position and the second position from the first position. When the cassette is located between the third position and the first position, which are separated by a predetermined distance toward the second position, the detection means is held at the fourth position, Holding means for holding the detecting means at a fifth position separated from the fourth position when the cassette is positioned between the position and the second position. Paper detection mechanism. 2. A paper feed cassette movable along a predetermined movement path between a first position inside the apparatus main body and a second position outside the apparatus main body, and a paper feeding cassette placed in the paper feeding cassette. A detection unit that detects the presence or absence of a sheet that is present, and a detection unit that is provided between a detection position located inside the movement path of the paper feed cassette and a retracted position located outside the movement path of the paper feed cassette. When the sheet feeding cassette moves from the first position to the second position, the cassette is held between the first position and the second position. The detection means is held at the detection position until it reaches the third position, and the detection means is maintained until the cassette reaches the second position after passing the third position. Hold the paper feed cassette in the retracted position, and When the cassette moves from the second position to the first position, the detecting means is held in the retracted position until the cassette reaches the second position from the second position, A sheet detecting mechanism comprising: a holding unit that holds the detecting unit at the detection position from when the sheet has passed the third position until the sheet reaches the first position.