JPS59223468A - Supporting means of developing device for copying machine - Google Patents

Abstract

PURPOSE:To position developing rolls in parallel with a latent image supporting body by constituting the titled means by a supporting shaft fitted to the leading end of a link pivotted to the side of a developing device, a bearing member fitted so as to support the supporting shaft and a separating member. CONSTITUTION:Under the state that the supporting shaft 11-a (11-b) of the developing device 6 is engaged with a bearing 2, movement in the Y, and Z axis directions and rotation around the X axis are restricted, and before sliding foils 5 are abutted to a drum 1, three degrees of freedom are yet left. Therefore, two lower sliding wheels 5 are abutted to the drum 1 by using two degrees of freedom, i.e. rotation around the Z axis and movement in the X axis direction, and then two upper sliding wheels 5 are abutted to the drum 1 by using the degree of freedom of rotation around the Y axis to position the developing rolls. Thus, the sliding wheels 5 are abutted to the both the ends of the drum 1 without fail at the two positions of the bearings 2 by rotating two links 10-a, 10-b independently. Even if the parallel property with the center axis (a) of the drum 1 is sheared, the developing rolls 3, 3' are positioned and a developing gap is kept accurately and uniformly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention 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 particularly relates to 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.

As a developing method for conventional 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. In this method, seven developing rolls are used to develop the latent image.
There are two known methods: one with a book and one with one or more sleeves.◇In both of these methods, in the magnetic brush development method, the sleeve surface of the magnetic roll and the m image carrier surface are The image quality, especially the image density, of the developed image changes depending on the distance between the two, or the gap.

In general, the smaller the gap (hereinafter referred to as the developing gap), the higher the density, and the larger the gap, the lower the density. Therefore, unless the developing gap is kept parallel and constant over the entire axial length of the magnetic roll, Even among the seven copies, uneven density occurs depending on the location.Also,
If the developing device is removed and reinstalled when repairing a copying machine, etc., 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. .

These matters require special attention when using a one-component magnetic toner as a magnetic developer. This is because compared to λ component development, which uses a mixed developer of carrier and toner,
This is because in component development, the development gap is small and the tolerance is narrow, so even a difference in the size of the same development gap causes a large density difference. 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 specified 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. λ bearings 2 for supporting the developing device 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. Furthermore, a support shaft 4 that fits into the bearing 2 is provided on the developing device side on a straight line parallel to the central axis of one of the developing rolls 3, 3I. The support shaft 4 is restrained in position by the bearing 2, but can rotate freely within the bearing 2.The developing device further includes a developing roll that comes into contact with the drum surface near both ends of the latent image carrier drum 1. λ sliding foils 5 are provided for every seven wheels. 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 kept 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, the bearing 2 (Dl
f"()'groove'throughL"t"drop fit into the support 41"1"1 receiver 2.One core of the developing device 6 is arranged so as to be located on the drum side with respect to the support shaft 4. Therefore, the developing device rotates around the support shaft 4 toward the drum, and stops when the sliding wheel 5 comes into contact with the drum surface, and is positioned.

FIG. 3 is a diagram showing another example of a conventional developing device attachment/detachment support mechanism. A support shaft 7 having an axis parallel to the drum center axis al is fixed to the copying machine body, and hooks are attached to the imager and imager at two straight positions parallel to the developing roll center axes b' and C'. 8 is provided. The developing device also has a total of sliding foils 5, one for each of the seven developing rolls, and when the hook 8 of the developing device is hung on the support shaft 7, the weight of the developing device causes the drum to move toward the l-side. It rotates around the support shaft 7, and when the sliding foil 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, firstly, the latent image carrier drum 1, the two developing rolls 3,
3' is to position the developing device so that the developing devices are parallel to each other while maintaining a predetermined developing gap 1. To this end, the developing device 6 is provided with two sliding foils 5 for every seven developing rolls, a total of 5 sliding foils 5, and a developing gap is maintained when all of these t are in contact with the drum.

Generally, in order to determine the position fdf of a three-dimensional object in a three-dimensional space, it is necessary and sufficient to constrain all six degrees of freedom (movement in three axes directions and rotation around these axes) of the object. 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 it is restricted, and movement in the Y-axis direction is restricted by a stopper member (not shown). Therefore, the remaining degree of freedom is only rotation around the Y axis, and from this it can be seen that positioning is completed when seven points of the developing device come into contact with another object.

In other words, the developing device 6 supported by the bearing 2 is positioned when seven of the sliding wheels 5 come 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 cup,
If the positional relationship between the axis c of one developing roll and the support cage 14 is incorrect, or if the developing device is assembled in a distorted manner, a situation will occur in which only the seven sliding wheels 5 are unevenly contacted.
Alternatively, a situation occurs in which the two sliding wheels 5 on either the left or right side of the developer i# unit are brought into partial contact, and 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, and also to ensure that the developing roll 3°3' of the developing unit and the supporting shaft 4 are parallel to each other with high accuracy. Since high accuracy is required in the plane-to-plane relationship between the parallel and parallel developing rolls 3 and 31 and the support shaft 40, 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 layer such as a developing roll.

Another object of the present invention is to ensure that a parallel developing gap is obtained without the uneven contact of the abutting members seen in the conventional ones, as described above, and to facilitate the operation of removing the developing device from the copying machine main body. It is an object of the present invention to provide a support mechanism for a developing device that is easy and reliable in positioning and can be driven from a main body of a copying machine.

Structure of the Invention In order to achieve the above object, a developing device support mechanism according to the present invention includes a link pivotally supported on a side surface of the developing device so as to be able to rotate in a plane parallel to the side surface, and a link 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 detachably support the support shaft, and a developing member positioned in a predetermined position relative to the latent image carrier. A separating member is attached to the supporting shaft so as to face each other with a gap of It is characterized by

Embodiments of the present invention will be shown from Figure 1 onwards, and the embodiments of the present invention will be described in detail using these figures.

In FIG. 7, the same members as those in FIG. λ bearings 2 for supporting the bearings 6 are fixed. here,
It is not necessary to maintain high accuracy 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, towards the developing device 6, there is a link 10-a which is rotatable in a plane parallel to the (I'm plane) of the developing device about shafts 9-a and 9-b.
.

10-b is attached and this link 10-a.

Support shafts 11-a and 11-b that protrude outward from the side surface of the developing device are supported on 10-b in parallel with the drum center axis a. The support shaft 11-a (11-b) is restrained in position by the bearing 2, but can rotate freely within the bearing 2, and the support shaft 1l-a (11-b) is
The imager 6 is still rotatable around the axis 9-a (9-b) even after the imager 6 is fitted and its position is restrained.

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 a separating member for maintaining a developing gap, that is, a part that comes into contact with the drum, such as a sliding wheel A.
15 are respectively provided at both ends of the developing rolls 3 and 3'. Of course, these wheels may also be wheels.

Next, the operation of the developing device support mechanism of the present invention will be explained. First, support shafts 11-a p1 provided on both sides of the developing unit 6 are attached to bearings 2, 2 fixed at locations on the copying machine.
1-Fit b. These support shafts 11-a e
Link 10-a supporting 11-b.

10-b can each be turned independently, so arrows d and e
This causes the two sliding wheels/I15 at both ends of the lower developing roll 30 to come into contact with the latent image carrier drum 1 (see Fig. S). ), then the rotation of the support shafts 11-a, 11-b of the developing unit 5 within the bearings 2, 2, and the links 10-a, 1 around the shafts 9-a, 9-b.
07b causes the two driving wheels 5.5 at both ends of the upper developing roll 3' to come into contact with the drum 1, causing the third and third driving wheels 5.5 to come into contact with the drum 1.
Figure (11)), this completes the installation.

The features of the developing device support mechanism of the present invention will be explained with reference to FIG. The support shaft 1l-a (11
-b) is fitted, 31 imager 6 (7
) Three degrees of freedom are constrained. That is, the Y axis,
Movement in the Z-axis direction 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 zIIIll, and movement in the X axis direction. Here, the rotation around the Y axis is mainly caused by the axis 9-a (9-
b) The rotation around the two axes is caused by the links 1O-a (10-b) of the left and right moss points independently rotating in opposite directions, and the movement 1j+ in the Vx axis direction. , the left and right links 1o-a (lo-b) at λ positions rotate in the same direction about the axis 9-a (9'-b).

Next, in order to position the developing device 6 11 from this state, it is necessary that at least three additional locations of the developing device come into contact with other members. Therefore, using one degree of freedom of rotation around two axes and movement in the X-axis direction, the lower two sliding wheels 5,
5 is brought into contact with the drum 1, and then, by using the degree of freedom of rotation around the Y axis, the two upper sliding wheels 115, 5 are brought into contact with the drum 1. All degrees of freedom are now constrained, and positioning is performed.

Regarding the problem of the parallelism of the straight line connecting the center axis a of the drum 1 and the centers of the λ bearings 2, which was mentioned earlier, in the conventional support mechanism (Figs. 7 and 3), the drum center axis a and the bearings 2 Or the support shaft 4 is out of parallel. Sometimes, as shown in FIG. 6, either one of the seven developing rolls or one of the developing rolls is supported in a state where one of the sliding wheels 5 is lifted from the drum, so the developing gap is as shown in FIG. This results in large non-uniformity, as shown by the straight line to . However, in the developing device support mechanism of the present invention, as described above, due to the independent rotation of the rotatable links 10-a and 10-b at λ positions on the left and right, the position of the bearing 2 at the moss position is not the same as before. The sliding wheel 5 always comes into contact with both ends of the drum without requiring precision. Therefore, even if the bearing 2 is not parallel to the drum center axis a when the bearing 2 is installed, the positions of the developing rolls 3 and 3' are determined as shown in FIG. 7, and the developing gap is as shown in FIG. 3 B. Like a curve, it only becomes narrower in the center than the standard value.

FIG. 9 shows the drive mechanism for the developing rollers 3, 3'. The drive gear 14 provided on the copying machine body engages with the seventh intermediate gear 15 in a state where the support shafts 11-a + 11-b are fitted into the bearings 2, 2, and this tooth rectangle 5 It meshes with a No. 1 intermediate gear 16 that rotates around the shaft 9-a (or 9-0b), and this gear 16 meshes with a gear 17 of the lower developing roll 3. It meshes with gear 18 of 3I. Therefore,
The developing rolls 3, 3I rotate synchronously by the 140 rotations of the drive teeth. In particular, the support shaft 4 and the shaft 9-a (or 9-a)
By arranging intermediate gears in each of b), the distance between the shafts used for transmitting driving force can be maintained constant even if the developing device rotates around the support shaft 4 due to vibrations around the drum 10, etc. . In addition, Fig. 9 shows an example of driving force transmission by gears.
However, it goes without saying that other means such as a chain, ladder chain, or timing belt may also 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. The straddle development method 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. Further, K can also be applied when one or both of the two developing rolls are replaced with a fur brush or the like.

Furthermore, the λ separation members such as sliding foils provided on the developing device do not necessarily have to come into direct contact with the latent image carrier, but rather with another positioning member fixed or supported on the main body of the copying machine. You can also make them touch each other. In addition, in the embodiment of the present invention, the developing unit is brought into contact with the drum by its own weight so that it can be easily attached and detached, but in the case where gravity cannot be used, an elastic member such as a coil spring or a plate spring is used. Pressure may be applied to press the developing device against the drum side.

Effects of the Invention As described above, the supporting mechanism of the developing device of the present invention is easy to operate, allows reliable positioning, and maintains a uniform developing gap with high precision. Furthermore, the attachment of the support member has the effect that even if the accuracy and assembling accuracy of the developing unit are low, there is little influence on the uniformity of the developing gap.

[Brief explanation of the drawing]

Fig. 7 is a perspective view of a conventional developing device support mechanism, and Fig. 2 is a perspective view of a conventional developing device support mechanism.
FIG. 3 is a side view of another conventional developing device supporting mechanism; FIG. 7 is a perspective view of the developing device supporting mechanism according to the present invention; FIG. 5(1) and (11) are side views showing the operation of the support mechanism according to the present invention, FIG. 6 is a plan view showing how the older developing roll is unevenly touched by the conventional support mechanism, and FIGS. 7 (1)' and ( 1) is a plan view and a front view showing how the developing roll is supported by the support mechanism according to the present invention, and FIG. 3 shows the distribution of the gap between the developing roll and the latent image carrier in the axial length of the developing roll. The graph shown in FIG. 9 is a side view of the developing device, showing the power transmission system of the support device 14 according to the present invention. 1...Latent image carrier drum, 2...Bearing, 3.3'...Developing roll, 4...
・Support shaft, 5...Foil as a separation member,
6...Developer, 7...Support shaft, 8
......Hook, 9-a, 9-b...Axis, 10-a*10-b...Link, 1
1-a, 11-b...Support shaft, 14-18
·········gear. Figure 1 Figure 2 Section 3 Figure 4 Figure 5 (i) (ii) Figure 6 Figure 7 (i) (ii)

Claims (1)

[Scope of Claims] A developing device equipped with a developing member is supported with a predetermined developing gap maintained between a latent image carrier of a copying machine and the developing member, and the developing device is separated from the latent image carrier. In a developing device support mechanism of a copying machine that can be removed by moving away from the developing device, a link is pivotally supported on the side of the developing device so as to be able to rotate in a plane parallel to the side surface, and a developing device is attached to the tip of the link. A support shaft is attached so as to protrude outward from the side surface of the machine, a bearing member is attached to the main body of the copying machine to removably support the support shaft, and a developing member is placed in a predetermined gap with respect to the latent image carrier. and a separating part I attached to the support shaft so as to face each other, and by attaching the support shaft to the bearing member, the developing member is positioned substantially parallel to the latent image support. Current equipment support machine 4 featuring
Iiv.