JPH08101466A - Original cover device for image forming device - Google Patents

Abstract

PURPOSE: To provide an original cover device capable of attaining effect prevention of shock at the time of closing an original cover and the stabilization of the closing posture of the original cover. CONSTITUTION: The original cover device is provided with a second energizing means 11 in addition to a first energizing means 6 for keeping balance with the original cover 1 in weight, the second energizing means 11 is composed of a cam body 12 provided with a first cam surface Sl and integrally turned with the original cover 1, a cam follower 13 driven according to the turn of the cam body 12 from the balanced state of the original cover 1 to just before it is fully opened and a spring 14 imparting energizing force against the fact that the came follower 13 is driven, to it. Moreover, in the cam body 12, a second cam surface S2 for imparting the energizing force in a closing direction by the spring 14 to the original cover 1 from just before it is fully opened, is formed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved technique for a document holding device provided in an image forming apparatus such as an electrostatic photocopier.

[0002]

2. Description of the Related Art As the above-mentioned document pressing device, a simple plate-shaped document pressing device, a document pressing device having an automatic document feeding device for feeding a document onto a contact glass, and further, the above-mentioned automatic document feeding device is provided with front and back documents. There is a document presser provided with a reversing function so as to be openable and closable and provided with a biasing means for biasing the document presser in the opening direction.

The above-mentioned urging means is provided in order to balance the weight of the document retainer and to open and close the document retainer lightly and effortlessly. The urging means rotates the document retainer. Since the biasing force uniquely changes depending on the corner, it is impossible to balance the weight in the entire opening and closing range of the document retainer.In addition, when the document retainer is closed, the document retainer is Since it is necessary to press against the contact glass surface, the rotational moment based on the weight of the document retainer overcomes the urging force of the urging means up to a certain opening angle of the document retainer, and the document retainer is closed. It goes without saying that the biasing force is set so that

[0004]

However, according to such a structure, when the document retainer is closed to the above-described certain opening angle, the rotational moment based on the weight of the document retainer causes the biasing force of the biasing means. Since the original presser that was open until then instantly switches to closing,
The document retainer was closed vigorously, and in particular, the document retainer equipped with the automatic paper feeder was heavy, so that it was possible to make a loud noise or even damage the contact glass. Of.

Here, by increasing the biasing force of the biasing means,
If the weight is balanced just before the document retainer is fully closed, the above inconvenience will be solved. However, this not only causes the original document retainer's closing posture to be unstable, resulting in insufficient document pressing force. The original presser foot is released by a slight shock, and the biasing force of the opening is large.Therefore, the original presser foot and the pivotal support structure receive an unreasonable shock at the opening end, and the original presser foot closes. There is a problem that operation becomes difficult.

The present invention has been made in view of the above circumstances, and it is possible to open and close the document retainer by an easier operation than ever before, and to effectively provide a shock when closing the document retainer. It is an object of the present invention to provide a document pressing device which can be prevented.

[0007]

The document pressing device according to the present invention, which has achieved the above-mentioned object, is provided with a first urging means for applying an urging force in the opening direction to the document pressing member and a document pressing member during the closing process. A second urging means for applying an urging force in the opening direction to the urging direction and switching the urging direction to the closing direction immediately before the full closing, wherein the second urging means is provided around the opening / closing axis of the document retainer. A cam body that has a first cam surface and rotates integrally with the document retainer; and a cam follower that is driven by the first cam surface as the cam body rotates until just before the document retainer is fully closed. A second cam surface for applying an urging force against the driven cam follower to the cam follower, and a second cam surface for applying the urging force of the spring to the document retainer in the closing direction immediately before the document retainer is fully closed. , Connected to the first cam surface It is characterized in comprising forming said cam member.

[0008]

According to such a construction, the urging force of the first urging means is set in the conventional manner so that the document retainer can be opened up to the above-mentioned certain opening angle, and the weight of the document retainer can be adjusted. When the rotational moment based on the first biasing means overcomes the biasing force of the first biasing means and the document retainer is switched to the closing bias, the second biasing means applies the biasing force in the opening direction to the document retainer for the first time. By applying the document, the document retainer can be slowly closed. However, since the pressing force of the second urging means is applied to the document pressing member in the closing direction immediately before the document pressing member is fully closed, the closing position of the document pressing member is stabilized and the pressing force of the document on the contact glass surface is maintained. Can be stronger.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a document pressing device of an electrostatic photocopier, which is an example of an image forming apparatus, and specifically, shows a structure of a pivotal attachment portion of a document pressing device 1 having an automatic document feeder for a copying machine main body 2. ing.

This pivotal structure is provided on both the left and right sides of the copying machine body 2 and the document retainer 1, and the details of the left and right sides thereof are shown in FIG. In these drawings, reference numeral 3 in the drawings denotes a holding member provided on the upper surface of the copying machine main body 2, and the document pressing member 1 is provided with the support shaft 4
It is pivotally attached to the pair of left and right brackets 5 and 5 via the so as to be openable and closable.

Reference numeral 6 denotes a first urging means for applying an urging force to the original pressing member 1 in the opening direction, which is the bracket 5 of the holding member 3.
Telescopic boxes 9a and 9b are connected to each other through the support shafts 7 and 8 between the document presser 5 and the document retainer 1, and two weights are balanced in the retractable boxes 9a and 9b to balance the document retainer 1. The springs 10 and 10 are provided.

Numeral 11 is a second urging means for switching the urging force between the opening direction and the closing direction and applying it to the original pressing member 1.
The state in which the document retainer 1 is in the middle of closing, more specifically, the rotation moment based on the weight of the document retainer 1 and the urging force of the first urging means 6 are balanced, and the document retainer 1 is held at a certain opening angle. In the closed state (see FIG. 4), the opening force is applied to the document retainer 1 from the state in the middle of the closing to immediately before the full closing, and the document retainer 1 is closed in the closing direction from immediately before the full closing. It has the function of applying the urging force of (1) and is configured as follows.

That is, the first portion around the opening / closing axis of the document holder 1
The cam body 12 having the cam surface S1 is integrally connected to both ends of the connecting support shaft 7 of the first urging means 6 (the connecting support shaft 4 of the document presser 1 or the document presser 1 itself may be provided. Then, the cam body 12 is integrally rotated with the document retainer 1 as the document retainer 1 is opened and closed, while the brackets 5 and 5 of the holding member 3 are provided with long holes in the front-rear direction. a, a
And the cam follower 13 driven by the first cam surface S1 in accordance with the rotation of the cam body 12 during the period between the closing of the document pressing member 1 and immediately before the closing of the document pressing member 1 described above. Two springs 14, 14 are provided over the holes a, a, and apply a biasing force against the driven of the cam follower 13 to the cam follower 13.
It is provided over the hook member 15 and the cam follower 13 on the copying machine main body 2 side, and further, after the document pressing member 1 is closed by the time immediately before it is fully closed, the urging force of the springs 14, 14 is closed against the document pressing member 1. The second cam surface S2 to be applied in the direction is connected to the first cam surface S1 and the cam body 12
Is formed.

According to the above structure, the second biasing means 11 functions until the closing operation of the document retainer 1, that is, the rotation moment based on the weight of the document retainer 1 and the first biasing means 6. As shown in FIG. 4, the urging force of the first pressing means 6 keeps the original pressing force until the original pressing member 1 is held at a certain opening angle. When the document retainer 1 is released during this time, the document retainer 1 is automatically switched to the fully open state shown in FIG.

When the document retainer 1 is further closed from the balanced state shown in FIG. 4, the second urging means 11 starts to function from here, and the document retainer 1 has the first cam surface S1 of the cam body 12 on it. The urging force of the springs 14, 14 in the opening direction is applied via the cam follower 13 and the cam follower 13. That is, if only the first urging means 6 is provided, the rotation moment based on the weight of the document retainer 1 is first applied with the closing operation of the document retainer 1 from the balanced state shown in FIG. The document holder 1 overcomes the biasing force of the biasing means 6, and the document holder 1 abruptly closes the contact glass surface. However, before the document holder 1 shown in FIG. By applying the urging force in the opening direction by the urging means 11 to the document retainer 1, the document retainer 1 can be slowly closed during this period.

However, from just before the document retainer 1 is fully closed to the closed state shown in FIG. 6, the urging force of the second urging means 11 acts on the document retainer 1 by the action of the second cam surface S2. Since the document pressing member 1 is applied in the closing direction, the document pressing member 1 can be stably held in the closed posture and the pressing force of the document against the contact glass surface can be increased.

In the above embodiment, the two springs 1 are used in both the first and second biasing means 6 and 11.
Although 0 and 14 are provided, the number of them does not matter, and the automatic document feeder 1 is provided with the automatic document feeder as the document retainer 1. It is possible to implement the present invention with a document retainer to which is added or a simple plate-like document retainer.

[0018]

As described above, according to the present invention, in addition to the first urging means for weight-balancing the original pressing member, the first urging member and the original pressing member function only for the first time after the balance. By providing the second urging means in the, without causing a large impact sound and damage to the contact glass,
The document retainer can now be closed slowly.

Moreover, from the state immediately before the document pressing is fully closed, the urging force of the second urging means is effectively used to apply the urging force to the document pressing in the closing direction. Thus, the closed posture of the document pressing member can be stably maintained, and the pressing force of the document against the contact glass surface can be strengthened. As a whole, it is rational to arrange the second biasing unit having a simple structure. With such a technical improvement, it has become possible to provide an original document holding device capable of opening and closing the original document pressing device with a more comfortable operation than that which can effectively prevent a shock when closing the original document pressing device.

[Brief description of drawings]

FIG. 1 is a sectional view of a main part of a document pressing device.

FIG. 2 is a perspective view of a structure of a pivot portion of a document pressing device.

FIG. 3 is a morphological view of a pivotal support structure in a fully opened state of a document retainer.

FIG. 4 is a morphological view of a pivotal support structure when the document presser is switched to a balanced state.

FIG. 5 is a configuration diagram of a pivotal support structure when the document retainer is switched to a state immediately before being fully closed.

FIG. 6 is a morphological view of a pivotal support structure when the document retainer is switched to a closed state.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Original document pressing, 6 ... 1st urging means, 11 ... 2nd urging means, 12 ... Cam body, 13 ... Cam follower, 14 ... Spring, S1 ... 1st cam surface, S2 ... 2nd cam surface.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromasa Hibi 1-2-2 Tamatsukuri Chuo-ku, Osaka City, Osaka Prefecture Mita Industry Co., Ltd.

Claims (1)

[Claims] 1. A first urging means for applying an urging force to the document retainer in the opening direction, and a urging force in the opening direction to the document retainer from the middle of closing, and the urging direction is closed immediately before fully closing. A second urging means that can be switched in a direction, the second urging means having a first cam surface around the opening / closing axis of the document retainer and rotating integrally with the document retainer; The cam follower is driven by the first cam surface in accordance with the rotation of the cam body until just before the document retainer is fully closed, and a spring that applies a biasing force against the driven cam follower to the cam follower, and The second cam surface for applying the urging force of the spring in the closing direction to the document pressing member immediately before the document pressing member is fully closed is formed on the cam body so as to be continuous with the first cam surface. Document holding device for image forming apparatus.