JPH05270668A - Copying machine - Google Patents

Abstract

PURPOSE:To provide a copying machine having a sheet tray provided with such a brake damper as to hold the approximately constant descending speed always regardless of the residual quantity of sheets at the time of forming the sheet base of the sheet tray of the copying machine into a natural descending system by gravity. CONSTITUTION:In a copying machine provided with a large capacity sheet tray, this sheet tray 10 has a sheet base 1 suspended elevatingly by plural wire ropes 2 wound in the freely wound-rewound state by pulleys 4 rotatably fitted to a winding shaft 3, and a drive source for lifting the sheet base 1 can be connected to one end of the winding shaft 3, whereas a brake damper 20 provided with a cam 11 and a brake plate 12 for holding the descending speed at the descending time of the sheet base l approximately constant is journalled to the other end of the winding shaft 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying machine, and more particularly to improvement of a large capacity paper tray used in the copying machine.

[0002]

2. Description of the Related Art As is well known, many proposals have already been made for copying machines, and in recent years, electrophotographic copying machines have become the mainstream. The basic configuration of such an apparatus is as follows: photoconductor drum / charging device / exposure device / developing device / transfer device /
A static eliminator / cleaner is arranged around the photoconductor drum to perform a series of electrophotographic processes, and as a path for copy paper, a paper tray / paper guide / paper feed roller / transfer device / suction unit (conveyance) / Fixing device / paper discharge roller is a basic structure, and the image transferred on the paper is fixed to obtain a copy. By the way, recently, along with the increase in size of copying machines, it has become necessary to increase the capacity of the paper tray, and this tendency is becoming stronger. Such a large-capacity paper tray is usually suspended by a wire rope, and the wire rope is driven up and down by a motor that is a drive source connected to the winding shaft via a pulley. In many cases, the motor can be mounted on the tray itself, and the motor can be rotated in the forward and reverse directions so as to be moved up and down.

An example of the structure of such a conventional large-capacity paper tray is shown in the perspective view of FIG. In this case, what is shown in the figure is the paper tray itself. Actually, as a paper tray unit, the tray shown in the figure is further housed in the drawer-like storage section, and the copying machine main body (not shown) is provided. The sheet tray itself is used so that it can be freely moved back and forth, but in order to simplify the explanation, only the paper tray itself will be focused here. First, in FIG. 4, reference numeral 10 denotes the entire paper tray, and 1 is a paper tray for the paper tray. The paper tray 1 is suspended by wire ropes 2 at its four corners, and the wire ropes 2 are attached to a take-up shaft 3. The pulley 4 is configured to perform winding / rewinding. Further, 5 is a motor which is a drive source of the pulley 4, and is provided with a coupling gear 6 for connecting with the winding shaft 3.

Next, 7 is a tray home position sensor which, when the paper tray 1 descends and reaches the bottom portion of the paper tray 10, the end of the paper tray 1 closes the gap of the sensor 7. The position of the paper tray 1 is detected by. Further, reference numeral 8 denotes an upper limit detection switch, and when the sheets are stacked on the sheet table 1 and the sheet tray 10 is set in the main body of the copying machine and is raised, the uppermost sheet on the sheet table 1 is the upper limit detection switch 8 By reaching the position and energizing it, a signal is sent to the motor 5 to stop the rise of the paper tray 1 and complete the preparation for paper feeding. The switch 8 is provided with a tip portion 8 of the switch 8 when there is no more paper on the paper tray 1.
Since a has entered the hole 9 provided in the surface of the paper tray 1 and the empty switch (not shown) is operated, it is detected that the paper has run out, and in this case, it functions as the operation of the empty switch. Will be done.

Next, the operation of the paper tray 10 of FIG. 4 having the above structure will be described. First, in the conventional paper tray 10, after the papers are stacked on the paper tray 1, the paper tray 10 is set in the main body of the copying machine and the drawer-like storage section is closed. Since it is driven in the winding direction, the wire rope 2 lifts the paper tray 1 by the pulley 4 via the winding shaft 3, and when the uppermost paper reaches the position for urging the upper limit detection switch 8, that is, the paper feed point. Then, the drive of the motor 5 is stopped by the signal, and thereafter, various arbitrary sheet feeding means such as a sheet feed-in roller system or air sheet feeding is adopted according to the sheet feed start timing of the copying operation of the copying machine. It is sent to the transfer section / fixing section by the normal process,
It is ejected as a copy. On the other hand, in the case of running out of paper, as described above, the empty switch is actuated by inserting the tip 8a of the switch 8 into the hole 9 on the surface of the paper tray 1, but even before running out of paper. It is necessary to replenish the paper on the way, especially in the case of large-scale continuous copying work.

In such a case, in any case, there is a means for pulling out the drawer-like storage portion from the main body of the copying machine to expose the paper tray 10, and then stacking a required amount of paper on the paper tray 1. It is necessary, and for that purpose, by activating the tray pull-out switch provided on the outer panel side of the storage unit (not shown), the motor 5 is first driven in the paper tray 10 to suspend the paper tray suspended by the wire rope 2. 1 is lowered by rewinding the pulley 4, and when the lower end of the paper tray 1 closes the gap of the tray home position sensor 7 installed at the bottom of the paper tray 10, for example, the gap of the photointerrupter, the paper tray 1 becomes the paper tray. 10 Since it has been detected that the bottom has been reached, it is possible to gradually pull out the drawer-shaped storage section at that time, and the paper supplement There becomes so performed, it is general that the system is taken as.

[0007]

The reason why many of the above-mentioned systems are used is mainly for safety reasons. In other words, due to the nature of its use, copiers are usually installed in ordinary offices, and therefore paper is replenished by the users of the copiers that perform copying, such as ordinary office workers. Is. Therefore, for safety, the motor 5 is operating and the pulley 4 is operating while the paper tray 1 is moving up or down.
The paper tray 1 is placed in the paper tray 1 because the
It is usual that the drawer-shaped storage portion can be pulled out only when it is lowered to the bottom of 0 and is bottomed. However, with such a configuration, when an attempt is made to replenish paper at an arbitrary time, the tray withdrawal switch is urged each time to wait for the paper tray 1 to reach the bottom of the paper tray 10. This is unavoidable, and during that time, paper cannot be replenished and the copying process is interrupted, which is disadvantageous in terms of work efficiency.

Therefore, in order to eliminate the waiting time when the paper table 1 is lowered and to improve the usability for the user, the paper table 1 is not affected by the tray pull-out switch.
Even when the paper tray 1 is in the middle position, the storage portion can be pulled out, and when the paper tray 1 is lowered, if the drawer portion is pulled out without driving the motor 5, the paper tray 1 is gravitated. If the structure is changed so as to naturally descend to the position of the tray home position sensor 7 in about 1 to 2 seconds, the paper can be immediately replenished and the waiting time can be shortened remarkably. On the other hand, on the other hand, it is naturally expected that the speed in the case of natural descent will change depending on the size of the remaining amount of paper, and if the amount of remaining paper is particularly large, the speed will be close to falling and noise will occur, which is a safety issue. Not only that, but it also has an unfavorable effect on the environment. Therefore, it is an object of the present invention to, when pulling out the paper tray 10 from the main body of the copying machine, lower the paper tray 1 naturally by gravity without operating the motor 5 and, moreover, reduce the amount of remaining paper, that is, the paper. It is an object of the present invention to provide a copying machine having a paper tray 10 configured so that the paper table 1 can always be lowered at a substantially constant lowering speed regardless of the weight and position of the table 1.

[0009]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its gist is to provide a copying machine equipped with a large-capacity paper tray, in which the paper tray is wound up. It has a paper tray that can be lifted and lowered by a plurality of wire ropes that are wound around and rewound by a pulley that is attached to a shaft. One end of the take-up shaft is used for raising the paper tray. While a drive source can be connected, a brake damper provided with a cam and a brake plate for keeping the descending speed at the time of lowering the paper table substantially constant is pivotally supported at the other end of the winding shaft. It's in a copier.

[0010]

According to the present invention, when the paper tray 1 of the paper tray 10 of the copying machine having the large capacity paper tray is raised, the winding shaft 3 is rotated by using the drive source such as the motor 5 only when the paper tray 1 is raised. While the wire rope 2 is wound up by the pulley 4, a brake provided with a cam 11 at the other end of the winding shaft 3 and a brake plate 12 biased by a spring 13 at the other end of the winding shaft 3 when the paper table 1 is lowered. Since the damper 20 is pivotally supported, the shape of the cam 11 and the position of the paper tray 1,
In addition, by experimentally obtaining the relationship of the load of the spring 13, the appropriate position of the cam 11 is brought into contact with the brake plate 12 and the spring 13 brakes according to the amount of remaining paper when the remaining amount is small. As a result, the brake corresponding to the remaining amount of paper is always operating on the paper table 1, so that the descending speed of the paper table 1 is kept substantially constant despite the natural descending by gravity. It becomes possible to keep.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing the configuration of a paper tray 10 according to an embodiment of the present invention, and FIG. 2 is a front view schematically showing the paper tray 10 of FIG. The basic structure of the paper tray 10 shown in FIGS. 1 and 2 is substantially the same as the structure of the conventional large-capacity paper tray shown in FIG. That is, reference numeral 10 denotes the entire paper tray, and the paper tray 1 is suspended by a plurality of wire ropes 2, for example, at four corners as shown in the drawing, and is wound by a pulley 4 pivotally mounted on a winding shaft 3. It is configured to be rewound. Further, as a drive source used for raising the paper tray 1 in the U direction, a motor 5 via a coupling gear 6 takes up the winding shaft 3.
It is provided to connect with. Further, with respect to the tray home position sensor 7, the paper tray 1 is also a paper tray 10.
The upper limit detection switch 8 for detecting that the bottom of the sheet has reached the upper limit, and the upper limit detection switch 8 for detecting that the sheet tray 1 has risen in the U direction to reach the upper limit, and the detection when the sheet runs out. The tip 8a of the switch 8 has a function as an operation source of an empty switch (not shown) for detecting a paper shortage by entering the hole 9, which is also similar to the conventional example shown in FIG.

On the other hand, in the present invention, unlike the configuration of FIG. 4, a brake provided with a cam 11 and a brake plate 12 for keeping the descending speed of the paper table 1 when it descends in the D direction by its own weight is substantially constant. The point where the damper 20 is pivotally supported by the other end of the winding shaft 3 is the main point. That is, as seen in FIGS. 1 and 2, the first brake gear 14 pivotally supported on the end portion of the winding shaft 3 meshes with the second brake gear 15 provided integrally with the cam 11. .. On the other hand, one end of the cam 11 is in contact with the brake plate 12 at the outer peripheral edge of the brake part 16 at the brake part 16.
2 is biased by a spring 13 so that pressure P is applied to the braking portion 16.

In this case, since the gist of the present invention is to keep the natural descending speed in the D direction due to its own weight when the paper tray 1 is descending, substantially constant regardless of the remaining amount of paper (weight), the shape of the cam 11 is , It is necessary to mold to meet such conditions. That is, as shown in FIG.
There Elevated x ₁ the position that is the upper limit, when the position where the lower limit lowered to y _1, since there is little remaining amount of paper in the x ₁ near less load, but lowering speed is small, the paper tray 1 As the position of becomes closer to y ₁ , the remaining amount of paper increases,
Since the load increases, the descending speed increases, and it approaches a fall. Therefore, when the position of the paper tray 1 is x ₁ , the cam 11 position where the minimum braking force is applied is x ₂ , and when the position of the paper tray 1 is y ₁ , the cam 11 position where the maximum braking force is applied is y _2.
With such a relationship, the shape of the cam 11 and the spring 13 having the spring constant are selected so that the descending speed of the paper tray 1 is always substantially constant. FIG. 3 is a graph qualitatively showing the relationship between the paper tray position / cam position and the spring load. By maintaining these constant relationships as shown in FIG. Regardless of the amount, it is possible to allow the weight to drop naturally due to its own weight.

Finally, the operation of the paper tray 10 of one embodiment of the present invention shown in FIGS. 1 and 2 will be described with reference to the drawings. First, the operation itself of the paper tray 10 in the main body of the copying machine (not shown) is basically the same as that of the conventional apparatus. That is, after stacking the sheets on the sheet tray 1,
When the drawer-shaped storage section is closed, a switch (not shown) is activated and the motor 5 functions as a drive source for raising the paper tray 1.
When the plurality of wire ropes 2 are wound by the pulley 4 via the winding shaft 3 and the paper tray 1 is lifted in the U direction, and the uppermost paper reaches a paper feed point for urging the upper limit detection switch 8, the switches are turned on. The drive of the motor 5 is stopped by the signal of 8, and thereafter, copying is performed according to the normal copying operation of the copying machine. In this case, when the paper runs out, the tip 8a of the upper limit detection switch 8 enters the hole 9 to operate an empty switch (not shown), which detects the paper out.

By the way, according to the present invention, not only when the paper is out, but also when there is a large amount of paper remaining on the paper tray 1, the tray drawer switch is energized and the motor 5 is driven as in the conventional case. When the tray home position sensor 7 detects that the paper tray 1 has completely reached the bottom of the paper tray 10, the drawer portion of the paper tray 10 is not opened until the motor 5, the wire rope 2, etc. are completely stopped. It is not necessary to wait for a long time to pull it out of the main body of the copying machine, and if the drawer portion is arbitrarily opened in response to a request for paper replenishment, the take-up shaft 3 and the motor 5 which is a drive source for raising can be opened. The paper table 1 is naturally lowered in the D direction by its own weight by a suitable known means such as disconnection from the coupling gear 6. At this time, if the remaining amount of paper is considerably large, simply letting it descend naturally by its own weight will cause the descending speed to remarkably increase, and it will be the same as a fall, which is not desirable for safety and also causes noise, which is also environmentally friendly. Not desirable. Therefore, in the present invention, in order to cope with this, the brake damper 2
0 is used.

That is, in the brake damper 20, the first brake is pivotally supported at the end of the take-up shaft 3 on which the pulley 4 for rewinding the wire rope 2 that suspends the paper tray 1 is mounted. Although the gear 14 meshes with the second brake gear 15, the second brake gear 15 is
1, the cam 11 is balanced by the pressure P applied to the brake plate 12 urged by the spring 13 at the braking portion 16 at the outer peripheral edge portion. Therefore, first, when the remaining amount of paper is small and the position of the paper tray 1 is close to x ₁ , the position x _{2 of the} cam 11 is set to the braking portion 1.
6, the brake plate 12 comes into contact with the brake plate 12, and the spring 13 in this case contracts considerably in the example of the drawing, so that a spring load is hardly generated. Therefore, in this case, a small braking force acts. On the other hand, when the remaining amount of paper is large and the position of the paper tray 1 is close to y ₁ , the cam 1
The position of the braking portion 16 gradually approaches y ₂ along the outer peripheral edge portion of 1, and the spring 13 gradually extends to increase the spring load. Therefore, in this case, a large braking force acts. By the operation of the system of the brake damper 20 as described above, it becomes possible to limit the descending speed of the paper tray 1 to a substantially constant size even in the case of natural descending.

[0017]

According to the present invention, when the paper tray 10 is pulled out from the main body of the copying machine, the paper table 1 is naturally lowered by its own weight without using a drive source, and at that time, regardless of the amount of remaining paper. Since the paper tray 1 can always be lowered at a substantially constant lowering speed, not only the structure of the paper tray 10 is simplified, but also from the viewpoint of safety for preventing fall and environmental protection for preventing noise generation. It is extremely desirable and its effect is immeasurable.

[Brief description of drawings]

FIG. 1 is a perspective view showing a structure of a paper tray according to an embodiment of the present invention.

FIG. 2 is a front view schematically showing the structure of the paper tray in the embodiment of the present invention.

FIG. 3 is a graph qualitatively showing the relationship between the paper tray position / cam position and the spring load.

FIG. 4 is a perspective view showing an example of the configuration of a conventional large-capacity paper tray.

[Explanation of symbols]

 1 Paper Stand 2 Wire Rope 3 Winding Shaft 4 Pulley 5 Motor 6 Coupling Gear 7 Tray Home Position Sensor 8 Upper Limit Detection Switch 9 Hole 10 Paper Tray 11 Cam 12 Brake Plate 13 Spring 14 First Brake Gear 15 Second Brake Gear 16 Braking part 20 Brake damper

Claims (1)

[Claims] 1. A copying machine having a large-capacity paper tray, wherein the paper tray is hung up and down by a plurality of wire ropes wound up and down by a pulley attached to a take-up shaft. With a lowered paper stand,
A drive source for raising the paper tray can be connected to one end of the take-up shaft, while the other end of the take-up shaft is provided for keeping the descending speed at the time of lowering the paper tray substantially constant. A copying machine characterized in that a brake damper provided with a cam and a brake plate is pivotally supported.