JPS63213833A - Original scanner - Google Patents

Abstract

PURPOSE:To secure a sufficient rail strength even in a maximum overhang state by projecting a first rail and a second rail to the side, where the extent of overhang of an original platen is larger, and to the opposite side respectively in the stop position of the original platen. CONSTITUTION:An original platen 2 is supported with a front rail 4, which prevents the rise of the original platen 2, and an original platen rail 5 engaged with an outer rail 6 and can be slided together with the outer rail 6 as one body. The outer rail 6 and an inner rail 7 are so constituted that they are projected from the original platen 2 to opposite sides in the moving direction of the original platen. When the copying operation is started, the original platen 2 is driven from the home position and is moved backward and is moved forward thereafter to start scanning synchronously with a photosensitive drum. When scanning is terminated, the original platen 2 is moved backward again and is returned to the stop position. Thus, a fitting length l considerably longer than that of conventional rails is secured to obtain a sufficient strength.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an original scanning device used in an image forming apparatus such as an electrophotographic copying machine with a movable original table, a facsimile machine, an image reader, and the like.

[Prior Art] Conventionally, in image forming apparatuses with a movable document table, slide rails, Accuride rails (product name), etc., which are composed of an actor rail and an inner rail, have been used as document table rails. The length of the outer rail and the inner rail are set equal according to the size in the moving direction of the document table, and the structure is such that the actor rail and the inner rail are aligned when the document table stops. Ta.

[Problems to be Solved by the Invention] However, in the above conventional example, when the amount of overhang of the document table (the amount by which the moved document table protrudes from the main body of the apparatus) increases, the fitting of the outer rail and the inner rail becomes difficult. Because the length becomes shorter,
In some cases, the rail deflects too much or is unable to withstand the load, resulting in damage to the rail when it is attached to the main body of the device.

Furthermore, the rail itself is generally made of metal material due to strength issues. For this reason, the longer the rail, the heavier it inevitably becomes, and in small-sized image forming apparatuses that are the mainstream type of image forming apparatus that moves the original table, the length of the rail has often been a bottleneck in reducing weight.

[Means for Solving the Problems] The present invention provides a method in which, at a stop position which is the home position of the document table, the first rails provided on the document table and the apparatus body alternately protrude in the opposite direction to the moving direction of the document table. It was configured as follows. As a result, even when the document table is overhanging, sufficient rails and rail attachments ensure the strength of the members, and the weight of the rails can be reduced by eliminating unnecessary parts. .

[Embodiment] FIG. 1 shows an embodiment of the present invention, which is composed of an outer rail 6 and an inner rail 7, which engage with each other and guide the movement of the document table. here,
As shown in the figure, the outer rail 6 and the inner rail 7 are configured to protrude alternately in opposite directions when viewed from the moving direction of the document table 2 with respect to the document table 2, but in the actual device, the document pressure plate (not shown) These rails are covered so that they cannot be seen.

To briefly explain the operation, the document table 2 is supported by a document table rail 5 that engages with a front rail 4 and an actor rail 6 to prevent lifting, and can slide integrally with this outer rail 6. There is.

When a copying operation starts, the document table 2 is driven by a rack and pinion or a wire from the home position shown in FIG. 1, and after first moving backward, it starts forward scanning in synchronization with a photosensitive drum (not shown). When the scanning is completed, the document table 2 is moved back again and returns to the stop position, that is, the position shown in the first diagram.

In this example, as shown in Fig. 2,
In order to improve operability when replacing the cartridge 8 that integrally supports a plurality of process means as described in the above publication, clearing jams, or cleaning the optical system, the upper frame body 9 is configured to be openable and closable. ing. In order not to interfere with this opening/closing operation, the document table is moved to a position where it protrudes further from the main body during the document operation described above (FIG. 2). For this reason, the document table 2 normally requires a travel amount larger than the travel amount at the time of copying, and at this time, the amount of overhang of the document table 2 with respect to the apparatus main body 1 becomes maximum as shown in the second diagram. In this state, if you put a tree on the document table or put your hands on it and apply loads in the six directions shown in the figure, the fitting of the actuator rail 6 and inner rail 7 will cause each rail to become distorted or bent. Although there is a risk that the document table 2 will come off and fall off from the main body of the apparatus, according to this embodiment, a fitting length 1, which is much longer than the fitting length JZ6 of the conventional rail, can be secured, so it is sufficient. It became possible to obtain strong strength. Furthermore, since only one side of the actuator rail 6 and inner rail 7, which is effective for increasing the rail strength during overhanging, is extended, the rail does not need to be extended unnecessarily, and weight increase can be minimized.

[Other Embodiments] FIGS. 3 and 4 show other embodiments, in which an exposure opening 11 for guiding a document image irradiated by an illumination lamp IO to a photoreceptor or a light receiving element is provided in an apparatus main body 1'. This is an example of a case where the position is closer to one side. In this case, the amount of overhang of the document table 2 is extremely different between the right and left sides as shown in FIG. It is clear that in the case of a device in which there is no problem in terms of strength in the state indicated by the two-dot chain line C, the rail fitting length in the state D is longer than necessary.

Therefore, in this embodiment, as shown in the fourth diagram, while ensuring the mating length between the outer rail 6' and the inner rail 7' in the state C, the mating length in the state D is reduced to the same level as the former, as shown in the figure. By doing so, it has become possible to significantly reduce redundancy and reduce costs without affecting performance.

Although the above description has been made using a copying machine as an example, the present invention is not limited to this.

[Effects of the Invention] As explained above, in the normal position of the document table of the document scanner of the document table movable type, the first rail is on the side where the document table overhang is large, and the second rail is on the opposite side. By adopting a configuration in which the rails extend in an alternating manner, it is possible to ensure sufficient rail strength even in the maximum overhang state. Furthermore, by removing unnecessary parts of the rail, we were able to effectively reduce the weight and reduce costs.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the wood layer side, and FIG. 2 is a front view of the overhanging state. 3 and 4 are front views of other embodiments. In the figure, 1. l', device main body 2: Original table 6.6'
, outer rail 7.7', inner rail blade 20

Claims (1)

[Scope of Claims] (1) In a document scanning device that uses a document table rail consisting of at least a first rail and a second rail that engage with each other to guide the movement of the document table, when the document table is stopped at the home position, the document table is stopped. A document scanning device characterized in that the first rail and the second rail protrude in opposite directions alternately in the direction of movement of the document table. (2) The document scanning device according to claim 1, wherein one rail projects on the side of the document table with a large overhang, and the other rail projects on the opposite side.