JPS58169162A - Developing device - Google Patents

Abstract

PURPOSE:To obtain an optimum contact state without straining too much nerves on assembling position relation, by bringing a belt for bearing a latent image into contact with a developing sleeve on the side of a drive roll outlet, that is, on the loosening side, so as to give a prescribed contact angle range. CONSTITUTION:A belt 4 for bearing a latent image is moved out with a drive roll 2 and contacts a developing sleeve 1 on the way to the next guide roll 3. Preferably, the rolls 2, 3 and the sleeve 1 are arranged so as to control the distance between the common tangent of the rolls 2, 3, that is, the line that the strongly strained belt forms, and the tangent of the sleeve 1 in parallel to said common tangent to about 0.5mm.. The belt 4 contacts the sleeve 1 on a loosened side driven out with the roll 2 rotated in the arrow direction, so it contacts actually the sleeve 1 at a conatct angle range of theta. Since the belt 4 contacts the sleeve 1 in a long range on the loosened side, a developer layer can be held between the belt 4 and the sleeve 1 with such a contact pressure as not damaging toner.

Description

[Detailed description of the invention] The present invention relates to a developing device.

In the developing devices of copying machines, facsimile machines, and other recording devices, electrostatic latent scratches on the latent image carrier that come into contact with the developing sleeve cannot be developed by the developer conveyed by the nose of the rotating developing sleeve. known, and various improvements have been proposed.

In a developing device of the type in which an endless belt-shaped latent image carrier is brought into contact with a developing sleeve, the present invention provides that when the belt-shaped latent image carrier stretched on a roller is brought into contact with the developing sleeve, if the contact pressure is high, the developing sleeve There is a risk of destroying the developer, and if the contact pressure is too low, there is a problem that development becomes uncertain.

In order to obtain an appropriate contact pressure, it is necessary to accurately adjust the tension of the latent image carrier and the relative positional relationship between the latent image carrier and the developing sleeve, which is a problem in that it is very time consuming.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and to provide a developing device in which an optimal contact state can be obtained without having to pay too much attention to the assembly positional relationship.

This object has been achieved by a developing device in which the belt, which is a latent image carrier, is brought into contact with the developing sleeve at a predetermined contact angle range on the exit side, that is, the slack side, of the drive roll.

The details of the present invention will be explained with reference to embodiments shown in the figures.

In the figure, developing sleeve lK drive roll 2 guide roll 3
An endless belt-shaped latent image carrier 4 wound around other guide rolls (not shown) is disposed in the developing device so as to be in contact with the developing sleeve l. At this time, the latent image carrier 4 is sent out from the drive roll 2 and comes into contact with the developing sleeve 1 on the way to the next guide roll 3. Preferably, the distance δ between the common tangent line of the drive roll 2 and the guide roll 3, that is, the line of the belt 40 in a taut state, and the tangent line of the developing sleeve l parallel to the line of the tensioned belt is about 0.5. Deploy. Since the drive roll 2 is driven in the direction of the arrow, the belt 4 is in contact with the developing sleeve 1 on the slack side, so it is actually in contact with the developing sleeve 1 within a contact angle range of only the angle θ (). Since the image carrier 4 is in contact with the developing sleeve 1 over a long range on the loose side, the developer layer is held between the latent image carrier 4 and the developing sleeve 1, and the developer layer is maintained at a contact pressure that does not damage the toner. Developer can be held between the latent image carrier 4 and the developing sleeve 1. Since the contact area was long even with a small contact pressure, sufficient development was achieved and a good effect was obtained.

As shown in the figure, the drive roll 2 of the latent image carrier is arranged above the developing sleeve 1, and the latent image carrier 4 is placed on the loose side.
Even better effects can be obtained if they are arranged relative to each other so that they can come into contact with the developing sleeve even with their own weight to some extent.

[Brief explanation of the drawing]

The figure is a schematic explanatory diagram of a developing device according to the present invention. 1...Developing sleeve 2...Drive roll 3.
...Guide roll 4...Latent image carrier procedural amendment document 1 Indication of the case 1982 Patent Application No. 50982 Hoof 2 Name of the invention Developing device 3 Person making the amendment Relationship to the case Patent Applicant P1. Refrigerated Book Name (Name) (674) Ricoh Co., Ltd. 4 Agent Address Kaji Kogyo Building 6, 32-4 Nishizaibashi 2J, Minato-ku, Tokyo Detailed description of the invention in the specification subject to amendment Column 1 Drawing 7, Contents of amendment (1) The statement "There was a problem that it was very time-consuming" on page 2, lines 11 to 12 of the specification of the present application was changed to "ensuring parts accuracy, and making the device more complex." There were problems such as compatibility.'' I am corrected. (2) Submit official drawings.

Claims (1)

[Claims] (1) In a developing device that has a developing sleeve that magnetically conveys developer along its circumferential surface and a latent image carrier that is placed in contact with the developing sleeve, the latent image carrier is guided by the driving roll. It is shaped like an endless belt wrapped around a roll.The drive roll is placed above the developing sleeve, and the part stretched between the exit side from the drive roll and the next guide roll has an appropriate angle range. A developing device characterized in that it is arranged so as to be in contact with a developing sleeve.