JPH0485264A - Detector for sheet loaded amount in picture forming device - Google Patents

Abstract

PURPOSE:To improve position accuracy of a detector while decreasing a number of part items in the sheet loading detector by using a shaft of a discharge roller in common for a rotary shaft of an actuator. CONSTITUTION:An actuator 25, arm 26 and a stopper 27 are integrally formed in a rotary shaft 24 of a discharge roller 21. A sheet S is conveyed in a direction of arrow mark A between conveying guides 22, 23, and the actuator 25 is lowered downward by its own weight and stopped by the stopper 27 to intercept a photointerrupter 28 by the arm 26. In the case of a sheet S, loaded and received onto a discharge tray 19, reaching a predetermined amount, the actuator 25 and the arm 26 are lowered down by the own weight, but the actuator 25 is brought into contact with the sheet S before the arm 26 reaches a position of intercepting the interrupter 28, and the arm 26 is stopped in a position not intercepting the interrupter 28. Consequently, the sheet S, loaded and received onto the discharge tray 19, can be recognized to reach the predetermined amount by continuing light transmitted by the interrupter 28.

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to an image forming apparatus such as a copying machine, a printer, etc.
More specifically, the present invention relates to a sheet loading amount detection device for ejected sheets in an image forming apparatus.

(b) Conventional technology A device for detecting the stacking amount of ejected sheets in a conventional image forming apparatus such as a copying machine or a laser beam printer is described in the 15th article.
This will be explained with reference to the drawings and FIG. 16.

In the figure, the sheet S on which the image has been fixed is guided by a conveyance guide a.
, b by a known conveying means in the six directions of arrows. When the leading edge of the sheet S comes into contact with the upper end of the actuator d protruding into the holes C of the conveyance guides a and b, the actuator d rotates clockwise around the rotation axis f against the elastic force of the tension spring e. and is rotated to the position indicated by the two-dot chain line in the figure.

At this time, the actuator d blocks light from the photointerrupter g, and therefore detects that the sheet S has begun to pass through the actuator d.

Next, as shown in FIG. 16, when the rear end of the sheet S passes through the actuator d, this actuator d is rotated counterclockwise by the tensile force of the tension spring e, and the upper end of the actuator d is again inserted into the hole. At the same time, the lower end of the actuator d comes into contact with the side wall J of the discharge tray l and remains stationary.

If the number of sheets S stacked and accommodated in the discharge tray i does not reach a predetermined amount, that is, the number of sheets S as shown in FIG.
With the loading amount, the sheet S does not come into contact with the actuator d, so the photointerrupter is not shielded from light by the actuator d.

Furthermore, when the sheets S are stacked up to the position indicated by the two-dot chain line in FIG. .

As a result, it is detected that the number of sheets S loaded on the discharge tray i has reached a predetermined amount.

(c) Problems to be Solved by the Invention However, in the conventional example, (1) the number of parts is large, assembly time is required, and costs are high (actuator d, rotating shaft f, tension spring e, photointerrupter g, k, That is, at least 5 members are required).

■Since the rotation axis f of the actuator d is separately attached to the main body, it is difficult to improve the positional accuracy of the actuator d, and the detection performance is not good.

There was a problem.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a sheet loading amount detection device that reduces the number of parts of the sheet loading detection device and improves its positional accuracy by sharing the axis of the discharge roller with the rotation axis of the actuator. It is something to do.

(d) Means for solving the problem The present invention has been made in view of the above circumstances, and includes:
For example, referring to FIGS. 1 and 2, a sheet (S
) and a loading member (19) for loading and accommodating the sheets (S
) to the stacking member (19); a discharge roller (21) that discharges the sheet (S) onto the stacking member (19); and a discharge roller (21) that contacts the sheet (S). In an image forming apparatus including an actuator (25) and a detection means (28) for detecting the state of the actuator (25), the actuator (25) is pivoted on a shaft (24) of the ejection roller (21). It is characterized by having been.

(Based on the configuration of one or more actions, the sheet (S) on which the image is formed is guided through the conveyance path (22, 23) and discharged onto the stacking member (19) by the discharge roller (21). (22, 23), the state of the actuator (25) in contact with the sheet (S) is detected by the detection means (22, 23).
8).

In the above, when the actuator (25) comes into contact with the sheet (S), the actuator (25) rotates around -(24) of the discharge roller (21).

Note that the reference numerals in parentheses are for illustrative purposes only, and do not limit equivalent configurations.

(f) Example Hereinafter, the present invention will be described in detail with reference to the drawings.

The first embodiment will be explained with reference to FIGS. 1 to 4. First, an outline of a laser beam printer 10 to which a sheet loading amount detection device is applied will be explained with reference to FIG.

Reference numeral 1 is a scanner unit that irradiates and scans a laser beam according to image information, and 2 is a process cartridge that is an image carrier, which houses a photosensitive drum 3, a primary charger 4 that is a corona discharger, and toner. It incorporates image forming means such as a developing device 5 and a cleaner 6.

The laser beam emitted from the scanner unit 1 is irradiated via the mirror 7 onto the photosensitive drum 3 charged by the primary charger 4 in the process cartridge 2 to form an electrostatic latent image. A toner image is formed and visualized.

On the other hand, the sheets S fed from the paper feed cassette 8 to the feed roller 9 are separated one by one by a separation pad 11 provided opposite to the feed roller 9. The separated sheets S are then separated by guide plates 12a and 1 provided above and below.
The image is formed on the photosensitive drum 3 by the pair of registration rollers 13a, 13b after being guided by the pair of registration rollers 13a, 13b, which is temporarily stopped, and the skew is corrected by being conveyed to the darkness. It is intermittently conveyed in synchronization with the leading edge of the toner image.

14 is a transfer charger for transferring the toner image formed on the photosensitive drum 3 onto the sheet S, and the sheet S to which the image has been transferred by the transfer charger 14 is transferred to the conveyor roller 1.
5 to the fixing device 16. The sheet S, on which the transferred image has been permanently fixed by the fixing device 16, passes through each transport path selected by the flapper 17 to the discharge tray 1.
8 or 19, respectively.

In FIG. 4, reference numeral 19 denotes a discharge tray which is a stacking member for stacking and accommodating discharged sheets S. This discharge tray 19 is provided so as to be inclined so that the rear end side (left side in the drawing) of the sheet S in the discharge direction is lower. On the upstream side of the discharge tray 19 in the sheet conveyance direction, there is a sheet S after recording.
A discharge roller 2 is a discharge means for discharging the material out of the device.
1 and a pinch roller 20 are provided. The discharge roller 21 is driven and rotated by a driving means (not shown), and the pinch roller 20 is pressed against the roller and driven to rotate, thereby sequentially conveying the sheets S and discharging them onto the discharge tray 19.

Conveyance guides 22 and 23 for guiding the sheet S are provided upstream of the discharge roller 21 and the pinch roller 20. This conveyance guide 22.23 is the sheet S
This forms a conveyance path from the flapper 17 to the discharge roller 21 and the pinch roller 20.

Next, the sheet loading amount detection device 30, which is the main point of the first embodiment of the present invention, will be explained in detail with reference to FIG.

An actuator 25 is rotatably attached to the rotation shaft 24 of the discharge roller 21. An arm 26 is integrally formed on this actuator 25, and a stopper 27 is also integrally formed on this arm 26. The photo-interrupter 28 is disposed in the main body of the laser beam printer 10, and when the stopper 27 comes into contact with the side surface of the photo-interrupter 28, the arm 26 blocks light from the photo-interrupter 28. 26, the stopper 27, and the photointerrupter 28 are arranged outside the limit line B of the sheet S discharge area so that they do not interfere with the sheet S discharge operation.

Next, the operation of the above embodiment will be explained with reference to FIGS. 2 and 3.

FIG. 2 shows a state in which the number of sheets S stored on the discharge tray 19 has not reached a predetermined amount.

The sheet S on which the image has been fixed is conveyed between conveyance guides 22 and 23 in the six directions of arrows. Before the sheet S is discharged, the actuator 25 moves downward due to its own weight and is stopped by the stopper 27 at the position indicated by the solid line in the figure, and the arm 26 formed integrally with the actuator 25 shields the photointerrupter 28 from light. are doing.

When the sheet S starts to be discharged by the rollers 20 and 21,
Since the sheet S passes through the position indicated by the two-dot chain line in the figure,
As the sheet S advances, the actuator 25 and the arm 26 rotate to the position shown by the dashed line in the figure, and the light-blocking state of the photointerrupter 28 is released.

When the sheet S is finished being discharged, the sheet S is placed on the discharge tray 19.
The actuator 25 and the arm 26 are loaded and stored on the top.
is lowered by its own weight to the position shown by the solid line in the figure, and the photo interrupter 28 is shielded from light by the arm 26, making it possible to recognize that the number of sheets S stacked and accommodated on the discharge tray 19 has not yet reached the predetermined amount.

As shown in FIG. 3, when the number of sheets S stacked and accommodated on the discharge tray 19 reaches a predetermined amount, the actuator 25 and the arm 26 move downward under their own weight, but the arm 26 pushes the photointerrupter 28. The actuator 25 comes into contact with the sheet S before reaching the light-shielding position, and the arm 26 stops at a position where the photo-interrupter 28 is not light-shielded.

Therefore, the photo interrupter 28 continues to transmit light, and the sheets S loaded and stored on the discharge tray 19
It can be recognized that the amount has reached a predetermined amount.

As described above, according to this embodiment, the actuator 25 rotates around the discharge roller shaft 24 and is urged downward by its own weight, so that the number of parts and assembly man-hours can be reduced. can reduce costs.

Further, since the actuator 25 is supported by the shaft 24 of the discharge roller 21, the positional accuracy of the actuator 25 is good, and the detection performance of the sheet loading amount can be improved.

Next, a second embodiment will be described with reference to FIGS. 5 to 7.

In this embodiment, the actuator 25 is pivotally supported at the center of the rotating shaft 24 of the discharge roller 21, and a projection 29 integrally extends upward from the shaft support of the actuator 25. 28 is disposed above the rotating shaft 24, and a stopper 31 is provided on the protrusion 29. When this stopper 31 comes into contact with the side surface of the photointerrupter 28, the tip of the actuator 28 is raised from a predetermined height. is also prevented from moving downward.

Further, FIG. 6 shows a case where the amount of sheets S stacked and accommodated on the discharge tray 19 has not reached a predetermined amount. This shows the same state as FIG. 2 in the first embodiment.

Further, FIG. 7 shows a case where the amount of sheets S stacked and accommodated on the discharge tray 19 has reached a predetermined amount. 1st
This shows the same state as FIG. 3 in the embodiment.

The operation of this embodiment is the same as that of the first embodiment, and the explanation thereof will be omitted.

The effects of this embodiment are the same as those of the first embodiment, and also have the following effects.

In the first embodiment, since the photointerrupter 28, the arm 26, and the stopper 27 must be disposed outside the sheet S discharge area, it can only be applied to an image forming apparatus based on one side.

In the second embodiment, since the photointerrupter 28, the protrusion 29 corresponding to the arm 26, and the stopper 31 are provided above the sheet S discharge area,
This embodiment is not subject to any restrictions on application, and can also be applied to image forming apparatuses based on a central reference.

Next, a third embodiment will be explained with reference to FIGS. 8 to 11.

In this embodiment, the path to the fixing device 16 of the first embodiment shown in FIG. The ejection roller 35, the pinch roller 3
6 is provided at the lower end of the discharge tray 32.

Then, the actuator 37 rotates the shaft 35 of the discharge roller 35.
It is pivoted on a. The shape of the actuator 37 is the same as that of the actuator 25 shown in FIGS. 6 and 7, and a protrusion 38 extends from the actuator 37, and a stopper 39 is integrally attached to the protrusion 38. A photointerrupter 40 is attached to the main body of the laser beam printer 10 and is shielded from light when the stopper 39 is engaged.

FIG. 9 shows a case where a predetermined amount of sheets S are not stacked on the discharge tray 32, and the protrusion 39 of the actuator 37 shields the photointerrupter 40 from light.

As shown in FIG. 10, when a predetermined amount of sheets S are stacked on the discharge tray 32, the protrusion 38 does not block the photointerrupter 40 from light.

In this way, the operation is the same as that described with reference to FIGS. 6 and 7. Therefore, the effect is also the same as that of the second embodiment.

Next, a fourth embodiment will be described with reference to FIGS. 12 to 14.

19 is a discharge tray provided on the upper surface of the laser beam printer 10 shown in FIG. In this embodiment, a discharge roller 41 is provided above the base end of the discharge tray 19, and a fan-shaped actuator 42 is pivotally supported at the center of a shaft 41a of the discharge roller 41.

A stopper 44 is integrally attached to this actuator 42, and this stopper 44 is adapted to be engaged with a side plate 19a of the discharge tray 19.
A coil spring 45 is interposed between the upper end of the actuator 3 and the actuator 42, and the actuator 42 is biased counterclockwise.

Further, a photo interrupter 46 is attached to the main body of the laser beam printer 10, and the actuator 42
As shown in FIG. 13, when the photo interrupter 46 is pressed by the left end of the sheets S stacked on the discharge tray 19, the actuator 42 blocks light from the photo interrupter 46. As shown in FIG.

Note that a pinch roller 47 is provided above the discharge roller 41.

As shown in FIG. 12, when the number of sheets S stacked on the ejection tray 19 is less than a predetermined amount, the sheets S do not press the actuator 42, so the actuator 42 is biased by the coil spring 45 so that the stopper 44 is placed on the ejection tray 19. The actuator 42 is rotated about the shaft 41a until it comes into contact with the side wall, and the actuator 42 does not block the photointerrupter 46. This makes it possible to recognize that the sheet S has not reached the predetermined amount.

Further, as shown in FIG. 13, the sheet S is
When a predetermined amount of sheets S are loaded on the sheet S, the left end of the sheet S causes the actuator 42 to rotate clockwise against the bias of the coil spring 45, so that the photointerrupter 46 is shielded from light by the actuator 42. This makes it possible to recognize that a predetermined amount of sheets S have been stacked on the discharge tray 19.

The effects of this embodiment are the same as those of the previous embodiment, and in addition, the ejection roller 41, photo interrupter 46, actuator 4
2 is arranged low, which has the effect of lowering the posture of the laser beam printer 10.

(G) As described in detail, according to the present invention, since the actuator is supported by the shaft of the discharge roller, at least the shaft supporting the actuator is omitted, thereby reducing the number of parts. , costs can be reduced.

Furthermore, the accuracy of the actuator support shaft can be improved compared to when the actuator support shaft is separately attached to the main body.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing a first embodiment of the present invention, FIG. 2 is a cross-sectional side view showing a state where a predetermined amount of sheets are not loaded on the ejection tray, and FIG. 4 is a sectional side view showing a laser beam printer according to the first embodiment of the present invention; FIG. 5 is a perspective view showing the second embodiment; FIG. The figure is a cross-sectional side view showing a state in which the sheet loading amount is less than a predetermined amount, FIG. 7 is a cross-sectional side view showing a state in which the sheet loading amount has reached a predetermined amount, and FIG. 9 is a cross-sectional side view of a laser beam printer; FIG. 9 is a cross-sectional side view showing a state in which less than a predetermined amount of sheets are loaded on the output tray; FIG. 10 is a cross-sectional side view showing a state in which the sheet has reached a predetermined amount; FIG. 11 is a perspective view of the third embodiment;
2 is a cross-sectional side view showing a state in which less than a predetermined amount of sheets are loaded on the discharge tray, FIG. 13 is a cross-sectional side view showing a state in which the sheet has reached a predetermined amount, and FIG. 14 is a fourth embodiment. FIG. 15 is a perspective view showing the fourth embodiment, and FIG. 15 is a cross-sectional side view showing a conventional example in which the number of sheets stacked on the discharge tray is less than a predetermined amount. FIG. It is a sectional side view showing a state. 19-... Loading member (discharge tray) 21-... Discharge roller 22, 23... Conveyance path (
Conveyance guide) 24--Axis 25-Actuator 28-Detection means (photo interrupter> S--Sheet manufacturer Canon Co., Ltd.

Claims (1)

[Claims] 1. A stacking member that stacks and accommodates sheets; a conveyance path that guides the sheet to the stacking member; a discharge roller that discharges the sheet onto the stacking member; an actuator that contacts the sheet; A sheet loading amount detection device for an image forming apparatus, comprising: a detection means for detecting a state of the actuator; and the actuator is pivotally supported on a shaft of the discharge roller.