JPH07144789A - Paper sheet detecting apparatus for paper feeding device - Google Patents

Abstract

PURPOSE:To smoothly perform the rotation action of a paper detecting lever for detecting the existence of a paper sheet to be fed. CONSTITUTION:A paper detecting lever 4, having an abutting arm 2 on one end side of a shaft part 1 and also a detecting arm 3 on the other end side of the shaft part 1, is provided, and also is rotatably provided around the center line of a shaft part 1 by retaining the shaft part 1 on retaining holes 6 and 7 formed on a support 5. Moreover the shaft part 1 is pushed in toward the retaining holes 6 and 7, and also push-in grooves 8, having opening width slightly smaller than the diameter of the shaft part 1 to be communicated with the retaining holes 6 and 7, are downwardly formed on the support 5. An adjusting arm 3, downwardly rotated when a fed paper sheet abuts on the abutting arm 2 to rotate the paper detecting lever 4, is positioned on the detecting arm 3 side to be provided on the shaft part 1. Also an elastic member 14, for upwardly energizing the adjusting arm 3 by abutting on the adjusting arm 3 downwardly rotated, is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet detecting device for a sheet feeding device in an image forming apparatus such as a copying machine or a printer.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus such as a copying machine or a printer is provided with a sheet detecting device for detecting the presence or absence of a sheet fed by a sheet feeding device. An example will be described based on FIGS. 4 to 7. First, a contact arm 2 extending in a direction substantially orthogonal to the shaft portion 1 is provided on one end side of the shaft portion 1, and a direction substantially orthogonal to the shaft portion 1 is provided on the other end side of the shaft portion 1. A paper detection lever 4 having a detection arm 3 extending to the inside is provided, and the paper detection lever 4 holds the shaft portion 1 in a pair of holding holes 6 and 7 formed in a holding body 5, and It is provided rotatably around the center line of the section 1.

Next, the shaft portion 1 which is communicated with the holding holes 6 and 7 and is held in the holding holes 6 and 7 is pushed into the holding body 5 from below toward the holding holes 6 and 7. A push-in groove 8 is formed downward, and the push-in groove 8 has an opening width slightly smaller than the diameter of the shaft portion 1.

Here, when the fed sheet 9 contacts the contact arm 2, the sheet detection lever 4 rotates about the center line of the shaft portion 1. A sensor 10 for detecting the presence or absence of the sheet 9 by detecting the displacement of the detection arm 3 is provided on the tip side of the detection arm 3.

In such a structure, FIG. 5 shows a state in which the paper 9 is not being fed, and the contact arm 2 is positioned so as to close the space between the upper guide plate 11 and the lower guide plate 12. The detection arm 3 is located outside the sensor 10.

FIG. 6 shows a state in which the sheet 9 has been fed. When the fed sheet 9 contacts the contact arm 2, the sheet detection lever 4 rotates about the center line of the shaft 1. Then
The contact arm 2 rotates upward and the detection arm 3 rotates.
Rotates downward and enters the sensor 10. The detection arm 3 that has entered the sensor 10 shields the light from the light emitting portion to the light receiving portion in the sensor 10, and the light shielding is performed so that the paper 9 is fed, that is, the paper is fed. The presence of the paper 9 to be printed is detected.

It should be noted that the fed sheet 9 is a pair of conveying rollers.
When it is conveyed by 3 and the contact state with the contact arm 2 is released, the sheet detection lever 4 rotates in the opposite direction around the center line of the shaft portion 1 and returns to the original position shown in FIG.

[0008]

When the sheet detection lever 4 is rotated to the state shown in FIG. 6 by the contact of the fed sheet 9 with the contact arm 2, the holding hole 6 in the shaft portion 1 is rotated.
An upward force acts on the portion held by the shaft portion 1 and the shaft portion 1 is pressed to the upper side of the holding hole 6 as shown in FIG. On the other hand, a downward force acts on the portion of the shaft portion 1 held in the holding hole 7 as a reaction force, and the shaft portion 1 is pressed to the lower side of the holding hole 7 as shown in FIG. 7B. To be

By this pressing, the shaft portion 1 bites into the pushing groove 8 communicating with the holding hole 7, and even if the contact state between the contact arm 2 and the paper 9 is released, the paper detection lever 4 is moved to the position shown in FIG. There is a drawback that the jam detection is performed by preventing the detection arm 3 from returning to the original position and the detection arm 3 continuously keeps the sensor 10 in the light shielding state for a set time or longer.

[0010]

The present invention has a contact arm extending in a direction substantially orthogonal to the shaft portion at one end side of the shaft portion, and the shaft portion at the other end side of the shaft portion. A sheet detection lever having a detection arm extending in a direction substantially orthogonal to the shaft is provided, a pair of holding holes for holding the shaft portion is formed in the holding body, and the shaft portion is pushed toward the holding hole. At the same time, a pushing groove having an opening width slightly smaller than the diameter of the shaft portion and communicating with the holding hole is formed downward in the holding body, and the fed paper is brought into contact with the contact arm. Paper is fed by rotating the paper detection lever around the center line of the shaft portion and rotating the contact arm upward, and detecting the displacement of the detection arm at the time of this rotation with a sensor. A paper feed that detects the presence of paper In the sheet detection device of the apparatus, an adjustment arm that rotates downward when the fed sheet abuts against the contact arm and the sheet detection lever rotates is located on the detection arm side. An elastic member that is provided on the shaft portion and that biases the adjustment arm upward by contacting the adjustment arm that is rotated downward is provided.

[0011]

According to the present invention, when the fed paper is brought into contact with the contact arm, the paper detection lever is rotated about the center line of the shaft and the contact arm is rotated in the upward direction. An upward force acts on the portion held in the holding hole near the contact arm, and a downward force acts on the portion of the shaft portion held in the holding hole near the detection arm as a reaction force. Works. However, during this rotation,
The elastic member abuts the adjustment arm located on the detection arm side and rotates downward, and biases the adjustment arm upward, so that the shaft portion is held in the holding hole on the side closer to the detection arm. An upward force is applied to this, and it is possible to prevent the portion of the shaft portion held in the holding hole on the side closer to the detection arm from biting into the pushing groove communicating with this holding hole. Further, when the contact state between the sheet and the contact arm is released and the sheet detection lever rotates in the opposite direction and returns to the original position, the urging force of the elastic member rotates the sheet detection lever in the opposite direction. Since the sheet detection lever acts in the moving direction, the sheet detection lever rotates in the opposite direction and returns to the original position smoothly.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. The same parts as those described in FIGS. 4 to 7 are designated by the same reference numerals, and the description thereof will be omitted. A contact arm 2 is provided on one end side of the shaft portion 1 of the sheet detection lever 4, and a detection arm 3 also serving as an adjustment arm is provided on the other end side of the shaft portion 1. The paper detection lever 4 is provided with a pair of holding holes 6 and 7 formed in a holding body 5 for holding the shaft portion 1 and rotatably around the center line of the shaft portion 1 for feeding. When the sheet 9 comes into contact with the contact arm 2, the contact arm 2 rotates upward and the detection arm 3 rotates downward. Further, the holding body 5 is formed with a pushing groove 8 for pushing the shaft portion 1 held in the holding holes 6 and 7 from below toward the holding holes 6 and 7.

Next, when the fed paper 9 abuts on the abutment arm 2, the paper detection lever 4 pivots downward when pivoting around the center line of the shaft 1. A sheet-shaped mylar 14 that is an elastic member that abuts on the detection arm 3 and biases the detection arm 3 upward is fixed to the upper guide plate 11.

In such a structure, FIG. 2 shows a state in which the paper 9 is not fed, and the contact arm 2 is positioned so as to close the space between the upper guide plate 11 and the lower guide plate 12. Therefore, the detection arm 3 is located outside the sensor 10 and separated from the mylar 14.

Next, FIG. 3 shows a state in which the sheet 9 is fed. When the fed sheet 9 abuts the abutment arm 2, the sheet detecting lever 4 rotates around the center line of the shaft 1. When the contact arm 2 rotates upward, the detection arm 3 rotates downward and enters the sensor 10, and the detection arm 3 enters the sensor 10 to feed a sheet. The presence of 9 is detected. Further, when the detection arm 3 rotates downward, the detection arm 3 comes into contact with the mylar 14, and the detection arm 3 moves toward the mylar 1.
It is urged upward by 4.

Here, the fed paper 9 contacts the contact arm 2
When the sheet detection lever 4 is rotated to the state shown in FIG. 3 by abutting against, the upward force acts on the portion of the shaft portion 1 held in the holding hole 6 and the shaft portion 1 is moved to the position shown in FIG.
As shown in (a), it is pressed to the upper side of the holding hole 6.
On the other hand, a downward force acts as a reaction force on the portion of the shaft portion 1 held by the holding hole 7, but at the same time,
An upward force acts on the portion of the shaft portion 1 held in the holding hole 7 by the urging force from the mylar 14.
Therefore, as in the case shown in FIG. 7A, the portion of the shaft portion 1 held in the holding hole 7 is also pressed to the upper side of the holding hole 7, and the shaft portion 1 is pushed into communication with the holding hole 7. It is prevented that the groove 8 is cut into.

Therefore, when the contact state between the contact arm 2 and the paper 9 is released, the paper detection lever 4 smoothly rotates and surely returns to the original position shown in FIG. Then, since the shaft portion 1 bites into the push-in groove 8, the sheet detection lever 4 cannot return to the original position shown in FIG. 2, and the detection arm 3 continuously keeps the sensor 10 in the light-shielding state for a set time or longer. This prevents jam detection. Further, when the sheet detection lever 4 returns to the original position shown in FIG. 2, the returning operation is smoothly performed by the urging force of the mylar 14. The biasing force of the mylar 14 is small and does not restrict the detection arm 3 from rotating downward.

In this embodiment, the case where the detection arm 3 also serving as the adjustment arm is provided and the mylar 14 is brought into contact with the detection arm 3 has been described as an example. When the detection arm 3 is rotated upward when the sheet detection lever 4 is rotated by contacting the sheet 2, the sheet 9 contacts the contact arm 2 and the sheet detection lever 4 rotates. When this is done, an adjusting arm that pivots downward is provided close to the detection arm 3 and separately from the detection arm 3, and the mylar 14 is arranged so that the mylar 14 contacts the adjustment arm.

[0019]

As described above, the present invention has a contact arm extending in a direction substantially orthogonal to the shaft portion at one end side of the shaft portion and the shaft portion at the other end side of the shaft portion. A sheet detection lever having a detection arm extending in a direction substantially orthogonal to the shaft is provided, a pair of holding holes for holding the shaft portion is formed in the holding body, and the shaft portion is pushed toward the holding hole. At the same time, a pushing groove having an opening width slightly smaller than the diameter of the shaft portion and communicating with the holding hole is formed downward in the holding body, and the fed paper is brought into contact with the contact arm. Paper is fed by rotating the paper detection lever around the center line of the shaft portion and rotating the contact arm upward, and detecting the displacement of the detection arm at the time of this rotation with a sensor. Paper feeding that detects the presence of paper In the stationary sheet detection device, an adjustment arm that rotates downward when the fed sheet abuts the contact arm and the sheet detection lever rotates is positioned on the detection arm side. Since the elastic member provided on the shaft portion and biasing the adjusting arm upward by contacting the adjusting arm rotated downward, the fed paper is brought into contact with the contact arm. When the paper detection lever rotates, an upward force acts on the portion of the shaft portion held in the holding hole on the side closer to the contact arm, and is held in the holding hole on the side closer to the adjustment arm on the shaft portion. A downward force acts as a reaction force on the open portion, but during this rotation, the elastic member comes into contact with the adjusting arm, so that the portion held in the holding hole on the side near the adjusting arm of the shaft portion Upward Since force is applied, it is possible to prevent the portion of the shaft portion held in the holding hole on the side closer to the adjustment arm from biting into the push-in groove communicating with this holding hole, and therefore the shaft portion is pushed in. It is possible to prevent the paper detection lever from returning to its original position because it got into the groove, and it is possible to prevent erroneous detection that a jam has occurred, and the contact state between the paper and the contact arm is released. When the sheet detection lever returns to its original position due to the above action, the biasing force of the elastic member acts in a direction to return the sheet detection lever to its original position, so that the sheet detection lever can be smoothly returned. And so on.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a side view showing a state in which paper is not being fed.

FIG. 3 is a side view showing a state where a sheet is fed and a sheet detection lever is rotated.

FIG. 4 is a perspective view showing a conventional example.

FIG. 5 is a side view showing a state in which paper is not being fed.

FIG. 6 is a side view showing a state in which a sheet is fed and a sheet detection lever is rotated.

FIG. 7 is a side view showing a state in which the shaft portion is held by the holding hole when the paper is fed and the paper detection lever is rotated. FIG. 7A shows the holding hole near the contact arm. The holding state of the held shaft portion, (b) is the holding state of the shaft portion held in the holding hole near the detection arm.

[Explanation of symbols]

 1 Shaft 2 Contact Arm 3 Detection Arm, Adjustment Arm 4 Paper Detection Lever 5 Holder 6,7 Holding Hole 8 Push-in Groove 9 Paper 10 Sensor 14 Elastic Member

Claims (1)

[Claims] 1. A contact arm extending in a direction substantially orthogonal to the shaft portion is provided at one end side of the shaft portion, and a contact arm extending in a direction substantially orthogonal to the shaft portion is provided at the other end side of the shaft portion. A sheet detection lever having an extended detection arm is provided, a pair of holding holes for holding the shaft portion are formed in the holding body, and the shaft portion is pushed toward the holding hole and is slightly smaller than the diameter of the shaft portion. A push-in groove having a small opening width and communicating with the holding hole is formed downward in the holding body, and the fed paper is brought into contact with the abutting arm so that the paper detection lever is moved to the shaft portion. The contact arm is rotated upward and the contact arm is rotated upward, and the displacement of the detection arm during this rotation is detected by a sensor so that the presence / absence of a sheet to be fed is detected. The paper detection device of the An adjustment arm that rotates downward when the fed paper contacts the contact arm and the paper detection lever rotates, and is provided on the shaft portion on the detection arm side. A sheet detecting device for a sheet feeding device, wherein an elastic member for urging the adjusting arm upward by contacting the adjusting arm rotated downward is provided.