JPH038547B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a developing device for an image forming machine, and more particularly to a developing device for an image forming machine that is most suitable for portability.

2. Description of the Related Art Demand for image forming machines such as copying machines has been increasing in recent years. The scope of demand is expanding not only to corporate offices, etc., but also to general households, and personal type products are being demanded. For example, a personal copying machine is functionally required to be small and lightweight, and at the same time, it is also required that the developer in the developing device does not leak out of the device and cause contamination when the device is carried.

An object of the present invention is to provide a developing device for an image forming machine that satisfies the above requirements.

Accordingly, the present invention provides a container containing a magnetic developer, a developing roller disposed in the opening of the container, which magnetically restrains the magnetic developer and conveys it to an image carrier, and the developing roller. The magnetic developer is not substantially magnetically restrained and exists at the bottom of the container along the developing roller when not being transported, and the magnetic developer that is not magnetically restrained during transport flows into the container. The developing device includes a plurality of partition plates provided along the axial direction of the developing roller.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a side sectional view of a personal type copying machine to which the present invention can be applied. A bar lens 2, a developing device 3, a charger 4, and a cleaner 5 are provided around the outer periphery of the photosensitive drum 1 inside the machine. A latent image is formed on the original image irradiated onto the photosensitive drum 1 through the bar lens 2 by a well-known electrostatic latent image process, and after development and visualization, it is transferred onto transfer paper and discharged outside the machine. The developing device 3 includes a container 3a containing developer;
It has a developing roller 3b and a doctor blade 3c, which generate a magnetic field, and are arranged along the open end substantially parallel to the photosensitive drum 1. Reference numeral 5 denotes a handle for carrying the copying machine, which is provided on the side wall 6 of the copying machine main body on the developing device 3 side with the photosensitive drum 1 as a reference. Therefore, when carrying the copying machine, grasp the handle 5 and lift it in the direction of the arrow 7.

FIGS. 2a to 2c are diagrams showing the flow state of the developer during the process of lifting the copying machine. Figure 2a
are normally placed and ready for copying at any time. A magnetic developer is contained in the developing device 3, and a doctor blade 3 is placed close to the upper side of the developing roller 3b.
It is unevenly distributed near c. This is because the developer conveyed to the photosensitive drum 1 side by the developing roller 3b is regulated into a suitable thin layer by the doctor blade 3c and accumulated. A cleaner 9 includes a cleaning blade 9a for cleaning the top of the photosensitive drum 1, and used magnetic developer that has been cleaned and removed is accumulated inside the cleaner. A magnet 9b is provided on the side wall of the cleaner 9 substantially parallel to the photosensitive drum 1. Therefore, if the handle 5 is grasped and lifted in the direction of the arrow 7, the state shown in FIG. 2b will be changed to the state shown in FIG. 2c. That is, at this time, the developer in the developing device 3 tends to flow into a horizontal state due to gravity. However, as can be seen from the state of the developer in the developing device in FIG. 2c shown in FIG. 3, in this state, the magnetic developer in the gap 10 between the container 3a and the developing roller 3b is Since the developer is in an agglomerated state in the gap 10, the developer is deposited above the gap 10 without flowing out.

Therefore, in order to set up the copying machine again, if the copying machine is set in the predetermined position according to the order of FIG. 2c, FIG. 2b, and FIG. flow to. That is, when the copying machine is returned to its original state by grasping the handle 5, the inertia due to the flow of the developer does not directly reach the gap 10, so the developer in the gap 10 is not pushed out, and the area around the developing device 3 is can prevent contamination.

On the other hand, in the cleaner, the developer is restrained by the magnetic pole 9b in the state shown in FIG. 2c. Therefore, when it is set in the predetermined position again, it will be in the state shown by the chain line in FIG. Since the developer is restricted to accumulate on the side, the filling efficiency of the container of the cleaner 9 can also be increased.

However, when lifting such a copying machine, it is not always possible to lift the copying machine so as to rotate it in the correct direction 7, 8 as shown in FIG. Therefore, in some cases, the developer in the developing device 3 may be transferred to the developing roller 3.
Accumulation may occur unevenly in the axial direction of b, especially in the vicinity of the stirring rod.

FIG. 3 is a side sectional view of a developing device showing an embodiment of the present invention. A plurality of partition plates 3d are provided 20 to 25 mm apart from the surface of the sleeve 3b' of the developing roller 3b and perpendicular to the sleeve. The magnetic flux density on the surface of the developing roller 3b is about 1000G, and the range of the magnetic field is about 25 mm. Therefore, since almost no magnetic field acts on the partition plate 3d, the partition plate may be made of either a magnetic material or a non-magnetic material.

A plurality of partition plates are provided at intervals of 20 to 40 mm in the axial direction of the sleeve 3b'. Of course, if this interval is too narrow, the developer between the partition plates 3d may cause crosslinking,
On the other hand, if it is too wide, the effect of preventing uneven distribution of developer in the axial direction of the developing roller 3b cannot be sufficiently exhibited. Therefore, the specifications of the partition plate 3d should be determined in consideration of the magnetic flux of the developing roller 3b, the fluidity of the developer, etc.

FIG. 4 is a diagram showing the distribution state of the developer inside the developing device 3. As shown in FIG. During normal copying, the developer is divided into developer A, which is magnetically restrained around the sleeve 3b', developer B, which is distributed near the stirring rod, and developer C, which is distributed between the partition plate 3d above the developer A. . Developers B and C are magnetically unrestricted and maintained in a fluidized state. When copying is continued using a document in which the amount of developer consumed is large at one end of the sleeve 3b' axis, the amount of developer first decreases in the order of developer A and developer B in that part, and then The developer in portion C compensates for the decrease in developer in portion C. When copying is continued and the toner in portion C decreases, the developer in portions B and C at the other axial end of sleeve 3b' is replenished by the action of the stirring rod. In this way, the partition plate 3d is provided in an area out of the reach of the magnetic field of the developing roller 3b', so it does not interfere with the movement of the developer.

Figure 5 shows the developing device 3 during transportation of a personal copying machine.
It shows the internal developer distribution. The developer A is magnetically restrained around the sleeve, and the developer D is distributed between the partition plates 3d. The developer D is magnetically unrestricted. The developer D is surrounded on all sides by the developer container wall, the magnetically restrained developer A, and the partition plate 3d. Therefore, even if the copying machine is tilted during transportation, the developer D will not move significantly in the axial direction of the sleeve 3b', the developer will not be unevenly distributed in the developer container, and the scattering of the developer can be minimized. Can be done.

According to the present invention, it is possible to obtain a developing device that prevents uneven distribution of developer along the magnetic field generating means within the developing device, which occurs when the image forming machine is carried.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a personal copying machine to which the present invention can be applied, FIGS. 2a to 2c are flow states of the developer when the copying machine is lifted, and FIG. 3 is an embodiment of the present invention. Side sectional view of a developing device showing an example, No. 4
The figure shows the state of the developer during normal copying, and FIG. 5 shows the state of the developer when the copying machine is lifted. 3... Developing device (developing device), 3b... Developing roller (magnetic field generating means), 3d... Partition plate (partition plate).

Claims (1)

[Scope of Claims] 1. A container containing a magnetic developer; a developing roller disposed in the opening of the container that magnetically restrains the magnetic developer and conveys it to an image carrier; The magnetic developer is not substantially magnetically restrained and exists at the bottom of the container along the developing roller when not being transported, and the magnetic developer that is not magnetically restrained during transport flows into the container. In the area,
A developing device comprising: a plurality of partition plates provided along the axial direction of a developing roller;