JPH0220109B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a support mechanism for a developing device in an electrophotographic copying machine, an electrostatic recording copying machine, etc., and more specifically relates to a supporting mechanism for a developing device equipped with a developing member such as a roll. This invention relates to a mechanism for detachably supporting a device on a copying machine main body.

PRIOR ART As a developing method for copying machines, a magnetic brush developing method is generally used in which a magnetic developer attached to a magnetic roll is brought into contact with or in close proximity to a latent image carrier such as a photoconductive drum. Two types of this system are known: one that has one developing roll for developing the latent image, and one that has two or more developing rolls. In any of these methods, in the magnetic brush development method, the distance between the sleeve surface of the magnetic roll and the surface of the latent image carrier, that is, the gap, changes the image quality, especially the image density, of the developed image. Generally, the smaller the gap (hereinafter referred to as development gap), the higher the density, and the larger the gap, the lower the density. Therefore, if the developer gap is not kept parallel and constant over the entire axial length of the magnetic roll, uneven density will occur at different locations within a single copy. Furthermore, if the developing device is removed and reinstalled when repairing the copying machine, if the developing gap is not always set at a predetermined value, there will still be a problem of variations in density from copy to copy. arise.

These matters require special attention when using a one-component magnetic toner as a magnetic developer. This is because, compared to two-component development that uses a mixed developer of carrier and toner, one-component development has a smaller development gap and narrower tolerances, so a difference in the size of the same development gap will result in a large density difference. be. Further, even in the case of a developing system having two or more developing rolls, care must be taken because the developing gap must be maintained at a predetermined value for each developing roll.

As mentioned above, the developing device in a copying machine is generally mounted so that it can be separated from the latent image carrier (most typically a photoconductive drum) for ease of assembly and maintenance. ing. This situation is shown in FIG. Two bearings 2 for supporting the developing unit 6 are fixed to the main body of the copying machine on a straight line parallel to the central axis a of the latent image carrier drum 1. Further, the developing device is also provided with a support shaft 4 that fits into the bearing 2 on a straight line parallel to the central axes b and c of the two developing rolls 3 and 3'. Although the support shaft 4 is restrained in position by the bearing 2, it can freely rotate within the bearing 2. The developing device is further provided with two sliding wheels 5 for each developing roll that come into contact with the drum surface near both ends of the latent image carrier drum 1. By coming into contact with the latent image carrier drum 1, the distance between the drum surface and the developing roll surface, that is, the developing gap, is maintained at a constant value. Next, the operation of this support mechanism will be explained using FIG. 2. When attaching the developing device 6 to the copying machine, insert the supporting shaft 4 of the developing device through the guide groove of the bearing 2.
into the bearing 2 and fit it. Since the center of gravity of the developing device 6 is located on the drum side with respect to the support shaft 4, the developing device rotates around the support shaft 4 toward the drum, and the sliding wheel 5 touches the drum surface. It stops when it makes contact and is positioned.

FIG. 3 is a diagram showing another example of a conventional developing device attachment/detachment support mechanism. The main body of the copying machine has a drum center shaft.
A support shaft 7 having an axis parallel to a' is fixed, and the developing device is provided with hooks 8 at two positions on a straight line parallel to the central axes b' and c' of the developing roll. The developing device also has a total of four sliding foils 5, two for each developing roll, and when the hook 8 of the developing device is hung on the support shaft 7, the developing device is supported on the drum 1 side by its own weight. It rotates around the shaft 7, and when the sliding wheel 5 comes into contact with the drum, it stops and is positioned.

Next, the drawbacks of these conventional developing device support mechanisms will be explained. The functions required for the support mechanism of the developing device are as follows:
First, the developing device is positioned in the copying apparatus so that the latent image carrier drum 1 and the two developing rolls 3, 3' are positioned parallel to each other while maintaining a predetermined developing gap. For this purpose, the developing unit 6 is provided with two sliding foils 5 for each developing roll, or a total of four sliding foils 5 for two developing rolls, and a developing gap is maintained in a state in which all four are in contact with the drum.

Generally, in order to position a three-dimensional object in a three-dimensional space, it is necessary and sufficient to constrain all six degrees of freedom of the object (movement in three-axis directions and rotation around these axes). This means that positioning is achieved when an object is constrained in contact with another object at a minimum of six points.

In the example of the conventional developing device support mechanism shown in FIG.
Rotation around the axis is restricted, and movement in the Y-axis direction is restricted by a stopper member (not shown). Therefore, the only degree of freedom left is rotation around the Y axis, and from this it can be seen that positioning is completed when one point of the developing device comes into contact with another object.
In other words, the developing device 6 supported by the bearing 2 is positioned when one of the sliding wheels 5 comes into contact with the drum, and there is no need for the other three sliding wheels 5 to contact the drum at the same time. do not have. If the bearing 2 is not installed parallel to the drum center axis a or a' in the copying machine, or if the positional relationship between the two developing roll axes b and c and the support shaft 4 is incorrect,
If the developing device is assembled in a distorted manner, a situation may occur in which only one sliding foil 5 is in uneven contact, or a condition in which two sliding wheels 5 on either the left or right side of the developing device are in uneven contact may occur. , the developing gap becomes non-uniform in the axial direction of the developing roll. For this reason, in the conventional support mechanism, when installing the bearing 2 in the copying machine, it is necessary to ensure that the bearing 2 is parallel to the drum axis a with very high precision.
3' and parallel to the support shaft 4, two developing rolls 3,
Since high accuracy is required in the positional relationship between the support shaft 3' and the support shaft 4, it is necessary to make the dimensional accuracy and assembly accuracy of various component parts extremely high.

OBJECTS OF THE INVENTION Accordingly, an object of the present invention is to provide a developing device support mechanism that can maintain a constant developing gap over the entire length of a developing member such as a developing roll.

Another object of the present invention is to reliably obtain a parallel developing gap without the uneven contact of the abutting member seen in the conventional ones, and to facilitate the operation of removing the developing device from the main body of the copying machine. It is an object of the present invention to provide a support mechanism for a developing device that is easy to position, can be positioned reliably, and can be reliably driven from a copying machine main body.

Composition of the Invention In order to achieve the above object, the developing device support mechanism according to the present invention includes links pivotally supported on both sides of the developing device so as to be able to rotate in a plane parallel to the side surfaces;
A support shaft is attached to the tip of the link so as to protrude outward from the side surface of the developer, a bearing member is attached to the main body of the copying machine to removably support the support shaft, and a developing member is attached to the latent image. and a spacing member attached to the support shaft so as to face the carrier with a predetermined gap, and by attaching the support shaft to the bearing member, the developing roll is almost separated from the latent image support. It is characterized by being positioned in parallel.

Embodiments Embodiments of the present invention are shown from FIG. 4 onwards, and the embodiments of the present invention will be described in detail using these drawings.

In FIG. 4, the same members as those in FIG. Two bearings 2 to support 6
is fixed. Here, it is not necessary to maintain accuracy as high as in the conventional example shown in FIG. 1, in which the straight line connecting the axial centers of the two bearings 2 and the drum center axis a are parallel. Next, on the side of the developing device 6, there is a link 10- which is rotatable in a plane parallel to the side surface of the developing device about shafts 9-a and 9-b.
a, 10-b are attached, and this link 10-
Support shafts 11-a and 11-a protrude outward from the side surface of the developing device in parallel with the drum center axis a on a and 10-b.
1-b is supported. Support shaft 11-a, 11
-b is restrained in position by bearing 2, but bearing 2
Even after the supporting shafts 11-a and 11-b are fitted into the bearings 2 and their positions are restrained, the developing device 6 can rotate freely within the shafts 9-a and 9-.
It is rotatable around b. These things occur in exactly the same way on the other side of the developing device, that is, on the b side. Also in the present invention, the developing device 6 includes two developing rolls 3, 3', for example, a sliding foil 5 as a separating member for maintaining a developing gap, that is, a member that comes into contact with the drum.
are provided at both ends of the . Of course, these wheels may also be shoes or the like.

Next, the operation of the developing device support mechanism of the present invention will be explained. First, the support shafts 11-a and 11-b provided on both sides of the developing device 6 are fitted into the bearings 2, 2 fixed at two locations on the copying machine. A link 10- that supports these support shafts 11-a and 11-b
Since a and 10-b can each be rotated independently,
It rotates as indicated by arrows d and e, which causes it to rotate around the Z axis and bring the two sliding foils 5 at both ends of the lower developing roll 3 into contact with the latent image carrier drum 1 (the fifth ), then the support shaft 11-a, 1 of the developing device 5.
Rotation within bearings 2, 2 of 1-b and shafts 9-a, 9
-B rotation of the links 10-a and 10-b causes the two driving wheels 5, 5 at both ends of the upper developing roll 3' to come into contact with the drum 1 (FIG. 5).
This completes the installation.

The features of the developing device support mechanism of the present invention will be explained with reference to FIG. 4 again. When the support shafts 11-a and 11-b of the developing device 6 are fitted into the bearing 2 of the copying machine,
Three degrees of freedom of the developing device 6 are restricted. That is, movement in the Y-axis and Z-axis directions and rotation around the X-axis are restricted. Therefore, before the sliding wheel 5 comes into contact with the drum 1, three degrees of freedom remain: rotation around the Y axis, rotation around the Z axis, and movement in the X axis direction. Here, the rotation around the Y-axis is mainly caused by the rotary tubes around the axes 9-a and 9-b, and the rotation around the Z-axis is caused by the two links 10-a and 10-b on the left and right independently opposing each other. Further, movement in the X-axis direction is obtained by rotating the two left and right links 10-a and 10-b in the same direction about the shafts 9-a and 9-b.

Next, in order to position the developing device 6 from this state, it is necessary that at least three additional locations of the developing device come into contact with other members. Therefore, by using the two degrees of freedom of rotation around the Z axis and movement in the X axis direction, the two lower sliding wheels 5, 5 are brought into contact with the drum,
Next, by using the degree of freedom of rotation around the Y axis, all six degrees of freedom of the developing device are restrained for the first time by bringing the two upper sliding wheels 5, 5 into contact with the drum 1. and positioning is performed.

The central axis a of the drum 1 mentioned earlier and the two bearings 2
Regarding the problem of parallelism of the straight line connecting the centers of As shown in FIG. 8, since either one of the developing rolls or both of the two developing rolls are supported in a state where the sliding foil 5 is lifted from the drum, the developing gap is as shown by the straight line A in FIG. This results in large non-uniformity. However, in the developing device support mechanism of the present invention, as described above, due to the independent rotation of the two pivotable links 10-a and 10-b on the left and right, the positions of the two bearings 2 are not as accurate as before. The sliding foil 5 always comes into contact with both ends of the drum without being required. Therefore, even if the bearing 2 is not parallel to the drum center axis a when installing the bearing 2, the positions of the developing rolls 3 and 3' are determined as shown in FIG. 7, and the developing gap is set as shown in FIG. As shown in curve B, it is only slightly narrower in the center than the standard value.

FIG. 9 shows a drive mechanism for the two developing rolls 3, 3'. The drive gear 14 provided in the copying machine main body has support shafts 11-a and 11-b that are connected to bearings 2 and 2.
In the fitted state, the first intermediate gear 15
This gear 15 meshes with the shaft 9-a or 9-b.
The gear 16 is meshed with a second intermediate gear 16 which rotates around the lower developing roll 3.
7, and the gear 17 meshes with the gear 18 of the upper roll 3'. Therefore, the rotation of the drive teeth 14 causes the developing rolls 3, 3' to rotate synchronously.
In particular, by arranging intermediate gears on the support shaft 4 and the shaft 9-a or 9-b, the driving force is maintained even when the developing unit rotates around the support shaft 4 due to vibration of the circumferential surface of the drum 1. The distance between the axes used for transmission remains constant. Although FIG. 9 shows an example of driving force transmission using gears, it goes without saying that other means such as a chain, a ladder chain, or a timing belt may be used.

Although the latent image carrier has been described so far as having a cylindrical shape, the present invention can of course be applied to cases where a belt-like or other shaped latent image carrier is used. Furthermore, the present invention can also be applied to various types of development methods that use a developer other than a dry magnetic developer or a development member other than a development roll. It can also be applied when one or both of the two developing rolls are replaced with a fur brush or the like.

In addition, there are two
The two separating members do not necessarily need to directly contact the latent image carrier, but may contact another positioning member fixed or supported on the main body of the copying apparatus. In addition, in the embodiment of the present invention, the developing device is brought into contact with the drum by its own weight so that it can be easily attached and detached, but if gravity cannot be used, an elastic member such as a coil spring or a plate spring can be used to hold the developing device. Pressure may be applied to press the drum against the drum side.

Effects of the Invention As described above, the developing device support mechanism of the present invention is easy to operate, allows reliable positioning, and maintains a uniform developing gap with high accuracy. Further, even if the mounting accuracy of the support member and the assembly accuracy of the developing unit are low, the uniformity of the developing gap is less affected.

[Brief explanation of drawings]

Figure 1 is a perspective view of a conventional developing device support mechanism;
The figures are a side view showing the operation of the support mechanism in Figure 1, and a side view showing the operation of the support mechanism in Figure 3.
4 is a perspective view of the developing device support mechanism according to the present invention; FIG. 5 is a side view showing the operation of the supporting mechanism according to the present invention; FIG. FIG. 7 is a plan view showing how the developing roll is supported by the support mechanism according to the present invention; FIG. FIG. 8 is a graph showing the gap between the developing roll and the latent image carrier as a distribution in the axial length of the developing roll, and FIG. 9 is a side view of the developing device showing the power transmission system of the support mechanism according to the present invention. be. 1...Latent image carrier drum, 2...Bearing, 3,
3'...Developing roll, 4...Support shaft, 5...Foil as a separating member, 6...Developer, 7...Support shaft, 8...Hook, 9-a, 9-b...Shaft, 10
-a, 10-b...link, 11-a, 11-b
...Support shaft, 14-18...Gear.

Claims (1)

[Scope of Claims] 1. A developing device equipped with a developing member is supported with a predetermined developing gap maintained between a latent image bearing member of a copying machine and the developing member, and the developing device is mounted on the latent image bearing member. In a developing device support mechanism of a copying machine that can be removed away from the developing device, a link is pivotally supported on both sides of the developing device so as to be able to rotate in a plane parallel to the side surfaces, and a link is provided at the tip of the link. , a support shaft attached to protrude outward from the side surface of the developing device, a bearing member attached to the copying machine main body to removably support the support shaft, and a developing member placed in a predetermined position relative to the latent image carrier. and a spacing member attached to the support shaft so as to face each other with a gap of 1, and by attaching the support shaft to the bearing member, the developing member is positioned substantially parallel to the latent image support. A developing device support mechanism characterized by: