JPH0130135B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a document table of an image forming apparatus, and more particularly to a document table of a movable document table type image forming apparatus.

Hereinafter, an explanation will be given using a copying apparatus to which electrophotography is applied as an example.

Some conventional copying apparatuses expose an original image onto a photosensitive member such as photosensitive paper or a photosensitive drum through a fixed slit portion while moving the original table.
As shown in FIG. 1, a document table 1 for such a copying apparatus is known, which has a relatively thin glass plate 2 fixed to the center of frames 3a and 3b as a transparent plate for placing the document. It is being In the figure, 4 is the front wall of the main body of the copying apparatus, 5 is the back wall thereof, and 6 is an L-shaped metal fitting fixed to the wall. A linear motion guide means 7 is fixed to the L-shaped metal fitting 6. Also, one side of the linear motion guide means 7 is fixed to the frame 3a. Note that a roller 8 is rotatably supported by the front wall 4 and supports the protrusion 3c at one end of the frame 3b. Further, 9 is also rotatably supported by a mounting plate 10 attached to the front wall 4 using rollers. When the rollers 9 press the protrusion 3c of the frame 3b against the rollers 8, the document table 1 may be inadvertently lifted, the linear guide means 7 may be deformed, the glass plate 2 may be damaged, etc. This prevents problems from occurring. However, in such a conventional document table 1,
There are problems as follows. That is, (a) in addition to the glass plate 2, it is necessary to provide a frame 3 to support the glass plate 2, and adding the size of the frame 3 makes the document table unnecessarily large; (b) the glass plate 2 The frame body 3 is required to be rigid in order to support the document table 1, which increases the weight of the document table 1, so that the device receives a large impact when the document table 1 is reversed or stopped; (c) the impact described in (b) above; There are problems such as a new absorption means is required and the mechanism becomes complicated.

Therefore, as a document table that solves the above-mentioned problems of heavy and large document tables, the document table is composed of a glass plate itself without using a frame, and the glass plate is used as a linear guide means. There is a fixed manuscript table.

FIG. 2 shows an example of a document table constructed without using a frame. The reference numeral 11 designates a glass plate constituting a document table, and the reference numeral 12 designates a support member for fixing the glass plate 11 to the linear guide means 13. Reference numeral 14 denotes an L-shaped metal fitting to which one side of the linear guide means 13 is fixed and which is fixed to the back wall 15 of the main body of the copying apparatus. A guide 17 serving as a guide member is fixed to the front wall 16 of the main body of the copying apparatus. The parallel portion 17a of the guide 17 is connected to the glass plate 11 constituting the document table.
When the document table, which receives the lower surface of the glass plate 11 and is guided by the linear guide means 13 and is driven, guides the other end of the glass plate. The upper portion 17b of the guide 17 is made of the glass plate 11 described above. This prevents problems such as deformation of the linear guide means 13 and damage to the glass plate 11 due to the document table being lifted carelessly.

However, in this document table, the upper portion 17b of the guide 17 as a floating prevention portion is located above the upper surface of the glass plate 11 of the document table. Therefore, if the document 18 placed on the glass plate 11 is large as shown by the broken line in FIG.
When the document 18 comes into contact with the upper part of the bending guide 17 and is pushed by a document cover (not shown) and the document table starts to move, the document 18 touches the top surface of the upper part 17b of the guide guide 17. Sliding may cause misalignment of the document during copying. This misalignment of the document during copying has an adverse effect, such as making the copied image unclear or misaligned.

SUMMARY OF THE INVENTION An object of the present invention is to improve the problems that the conventional document table has, and to prevent the document table from being lifted carelessly without the need for a special frame.
Furthermore, even if a large-sized original is placed on it, it will not bend, and if the large-sized original comes into contact with the floating prevention part of the guide member and slides, the original will not shift or the image position will shift. The purpose of the present invention is to provide a lightweight and small document table that does not require any additional work.

The configuration of the present invention that achieves the above object includes: a document table that is provided in an image forming apparatus so as to be movable in a reciprocating manner; A document cover that presses down the document placed thereon, a drive means that reciprocates the document placement transparent plate, and a linear motion guide that linearly guides one side of the document placement transparent plate that is reciprocated by the drive means. a chamfered portion provided on the side opposite to the one side of the transparent document placement plate; a horizontal support portion that slidably supports the lower surface of the transparent document placement plate on the side of the chamfered portion; and a guide member having a floating prevention part that prevents the document placement transparent plate from lifting up, and the floating prevention part has an uppermost surface that is lower than the uppermost surface of the document placement transparent plate. The document table of the image forming apparatus is characterized in that the document placed on the transparent plate does not come into contact with the uppermost surface of the floating prevention section or is configured so low that the document comes into contact with its own weight.

The present invention will be explained below with reference to the drawings.

FIG. 3 shows a sectional view of a document table of a copying apparatus to which an embodiment of the present invention is applied. In the figure, reference numeral 19 denotes a document table using an embodiment of the present invention, 20 a glass plate as a document placement transparent plate for placing a document, and 2
Reference numeral 1 denotes a support member that holds one end edge of the glass plate 20 in the reciprocating direction from above and below. In addition to the glass 20, the support member 21 supports a document cover 22, which is made of rubber, elastic resin, or the like, and functions to press the document onto the glass plate 20. Note that this cover 22 can be opened and closed in the direction of the arrow (indicated by A in the figure). Further, one of the rails of the linear motion guide means 23 is fixed to the support member 21 . The other rail that fits with the rail on the support member 21 side is fixed to the rail support member 24 . Further, the rail support 24 is fixed to a back wall 25 of the main body of the copying apparatus. Note that the member 26 holding the right end of the glass plate 20 in the figure is
A guide 26 serving as a guide member is fixed to the front wall 27 of the main body of the copying apparatus. The horizontal support portion 26a, which is the portion of the guide 26 that comes into contact with the glass plate 20 and guides the glass plate 20 parallel to the main body of the copying apparatus, is provided with a sliding member made of Teflon or the like having a low coefficient of friction. The right end side of the glass plate 20 is movably supported.

Therefore, the driving side of the document table 19 is supported by the linear guide means, and the other end side is supported by the guide 26. With the above configuration, the document table 19 is supported horizontally by the main body of the apparatus.

Below is a fourth partially enlarged view of the right end side of the glass plate 20.
This will be explained in more detail using figures. The glass plate 20 of the document table 19 is provided with a chamfered portion 20a on its right end side, that is, a slope that descends toward the end. Then, along the chamfered portion 20a, that is, facing the chamfered portion 20a, the guide guide 26
A glass plate holding part 26b serving as a hook-shaped floating prevention part provided at the upper part of the glass plate 20 is positioned with a slight gap between the glass plate 20 and the glass plate 20. That is, the guide 26 includes a horizontal support portion 26a for holding and guiding the glass plate 20, and a chamfered portion 20a of the glass plate 20.
A hook-shaped glass plate holding part 26b provided along
It has the following. The top surface of this hook-shaped glass plate holding part 26b is provided lower than the top surface of the glass plate 20. As a result, the original platen 1
Even if the original placed on the glass plate 9 is large, it will not touch the top surface of the glass plate holding part 26b, or if it is thin and sag, it will not be forced into contact with it by its own weight, and will not bend or become loose. Make sure to close the document cover 22
The document will not be misaligned. Moreover, even if the document table 19 made up of the glass plate 20 is inadvertently lifted up even though the top surface of the glass plate holding portion 26b is configured to be lower than the top surface of the glass plate, the chamfering of the glass plate 20 The portion 20a is securely restrained by the hook-shaped glass plate holding portion 26b of the guide 26. Therefore, the glass plate 20 is never lifted. Furthermore, since the side edges of the glass plate are chamfered, the glass plate is less likely to break or crack, increasing its strength.
Further, as described above, since there is a small gap between the glass plate 20 and the glass plate holding part 26b, the movement of the document table 19 along the linear guide means 23 can be blocked. It will not have any negative impact. Note that by providing a sliding member with a small friction coefficient on the surface of the glass plate holding part 26b facing the chamfered part 20a of the glass plate 20, it is also possible to eliminate the gap and bring the two into direct contact. Further, the glass plate holding part and the horizontal support part for holding and guiding the glass plate do not have to be integrated as in this embodiment, but may be provided separately.

Further, FIG. 5 shows another embodiment.

In this embodiment, rollers 28 are arranged on a horizontal support portion 26a that guides the glass plate 20 and the glass plate 20 of the guide 26 in parallel with the main body of the copying apparatus. The roller 28 is pivotally supported by the front wall 27 of the main body of the copying apparatus. According to this embodiment, the guide 2
6 and the glass plate 20 are not in direct contact with each other.
Since the document table can be moved, the document table can be moved more smoothly.

In each of the embodiments, an example is shown in which the chamfer is provided on one side edge in the direction of movement of the document table, but the chamfer and the restraint means may be provided at multiple locations on any side edge of the document placement section. Of course. Further, the shape of the chamfer is not limited to providing an inclined surface, but may be a shape that gives a rounded shape.

Note that FIG. 6 shows a drive mechanism for a document table using an embodiment of the present invention. In FIG. 6, reference numeral 28 denotes the main body of the copying apparatus, and 29 a pulley, which is rotatably supported by the main body 28 of the apparatus. The wire 32, which has both ends 30 and 31 fixed to the document table 19, is rotated in the direction of the arrow by the driving of the driving means M and the operation of the clutch means 33, so that the document table 19 is moved to the device 28.
Perform reciprocating motion at the top.

As described above, the document table of the present invention does not require a special frame, and the document table will not be lifted up carelessly. Further, according to the present invention, even if a large-sized original is placed, it will not bend, and the large-sized original will not shift when it comes into contact with the floating prevention part of the guide member and slide, and the image It is possible to provide a lightweight and compact document table for an image forming apparatus that does not shift its position.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of the conventional document table;
4 is an enlarged sectional view of the chamfered portion thereof. FIG. 5 is a sectional view of the document table using another embodiment of the present invention. FIG. FIG. 3 is a side view showing a drive means for the document table. In the figure, 1...Original table, 2...Glass plate,
3a, 3b...frame body, 7...linear guide means, 8...
... Rotating roller, 11 ... Glass plate, 12 ... Support member, 13 ... Linear motion guide means, 17 ... Guide guide, 17a ... Parallel part, 17b ... Upper part,
19...Original table, 20...Glass plate, 20a...
Chamfered portion, 21... Support member, 23... Linear guide means, 24... Rail support, 26... Guide guide, 26a... Horizontal portion, 26b... Glass plate presser, 28... Roller.

Claims (1)

[Scope of Claims] 1. A document table provided in an image forming apparatus so as to be movable in a reciprocating manner, on which a document is placed, a transparent document placement plate that is movable in a reciprocating manner, and a document placed on the transparent document placement plate. a document cover that holds down a document; a driving device that reciprocates the document placement transparent plate; a linear guide device that linearly guides one side of the document placement transparent plate that is reciprocated by the drive device; A chamfered portion provided on the side opposite to the one side of the transparent document placement plate; a horizontal support portion that slidably supports the lower surface of the transparent document placement plate on the side of the chamfered portion; and a horizontal support portion provided facing the chamfered portion, and a guide member having a floating prevention part that prevents the transparent document placing plate from floating; 1. A document stand for an image forming apparatus, characterized in that the placed document is configured so low that the placed document does not come into contact with the uppermost surface of the floating prevention section or comes into contact with it due to its own weight.