JPS6236237A - Sheet feeder - Google Patents

Abstract

PURPOSE:To shorten the transport path for making the device in small size by arranging the leading edge of a placed sheet right under a recording medium, causing contact in the timing that the surface of the recording medium is approaching, and by feeding sheets separately one after another through the use of the electrostatic force. CONSTITUTION:Sheets 2 are placed on an inside plate 6 installed within a cassette 3 and heaved by a spring 5, and a solenoid 4 lifts them through a cam 18 and a bottom plate 24 immediately before that developing surface of recording medium 1 to which toner 10 is attached is going to reach the lower part. The leading edge of the sheets 2 contacts said developing surface of the recording medium 1, and only the uppermost sheet 2' is separated by the static electricity generated there. In case friction force and/or electrostatical force acting between sheets is too strong, said static electricity on the recording medium 1 may not surely separate the sheets, and therefore a friction roller 9 is furnished so that the sheets are pressed by it at the same time as contacting the recording medium 1 to be transported at the same peripheral linear speed therewith, which ensures well separation of the sheets liable to attach to one another.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper feeding mechanism for recording paper in a paper feeding device such as an electrophotographic printing device, and in particular, the present invention relates to a paper feeding mechanism for recording paper in a paper feeding device such as an electrophotographic printing device. The present invention relates to a paper separation mechanism unit that separates paper every time.

[Conventional technology]

Conventionally, paper is automatically fed into copying machines, printing machines, etc. (This is a method that uses air suction, frictional force from rubber rollers, or a combination of both to feed a large number of sheets of paper one by one. Methods such as air suction and methods that combine air suction and friction force are mainly used in printing machines aimed at high-speed paper feeding, but the devices are complex and large. Furthermore, there are disadvantages such as relatively large noise due to the use of pumps and the like during operation, and high cost.

On the other hand, methods that utilize the frictional force of rubber rollers and the like are used in relatively slow and simple printing devices such as copying machines and printers.

! Figure 2 shows a general structural diagram of the system. In the figure, when the cassette 3 containing the paper 2 is inserted into the paper feed port 17, the paper 2 is fed through the middle plate 6, which is rotatable at one end, by the spring member 5, and the curvature of the outer diameter of the paper feed roller 9 is The cassette 3 is in pressure contact with the cassette 3 and is held in a state where it does not come into contact with the notch, and the installation of the cassette 3 into the main body is completed.

Further, a plurality of paper feed rollers 9 are arranged in parallel in the paper width direction.

After the cassette 3 is installed in the main body, a rotational driving force is applied to the paper feed roller 11 by a paper feed signal ζ from the main body controller (not shown). l'1I20, and the rotation of the paper feed roller 9 starts. The paper 2 comes into contact with the curvature of the paper feed roller 9, and since the frictional force between the paper feed roller and the paper is higher than the frictional force between the sheets, the paper 2 is separated one by one from the top of the stacked papers. be done.

Next, the separated paper 2 is inserted between the rotating transport rollers 5 and 16. The rotational driving force is driven by the drive roller 1.
51+111t Pressure roller 16i is in pressure contact with the trowel to prevent slippage when paper is inserted. Then paper 2
The toner is transported to an electrophotographic process system centering on a recording carrier 1, and is charged 12 and exposed 13 to form an electrostatic latent image on the surface of the recording carrier 11. The developed toner is transferred 71- to paper. The paper is then separated from the recording carrier 1 by a separation belt 8 and conveyed to a fixing device 21.

[Problems to be Solved by the Invention] However, the conventional paper feeding device as described above is configured with a conveyance process of separation, paper feeding, and transfer, making it difficult to downsize the device. Furthermore, since the conveyance process is long, it is difficult to cause so-called jams, in which the paper gets caught during conveyance and the conveyance is interrupted, or skew, in which the paper becomes oblique during conveyance.

In addition, in some cases, the paper cassette 3 is completely inserted into the device from the viewpoint of operability of the device, but in this case as well, it is necessary to have a structure in which the conveyance section is made into two stages and the paper is reversed, which increases the height of the device. [Means for solving the problem] In view of the various drawbacks of the conventional paper feeding device as described above, the present invention has developed a new paper feeding device. The purpose is to provide a paper device, and its configuration is such that the paper leading edge of the paper feeding device is placed adjacent to the recording carrier, and is aligned with the approach of the recording carrier surface developed by an electrostatic latent image. The structure is such that the leading edge of the paper is brought into contact with the surface of the recording carrier, and the electrostatic force of the recording carrier separates the paper sheets one by one.

〔Example〕

FIGS. 1-fa) and (b) show structural sectional views of the system according to the present invention. FIG. 1-fa) is a sectional view when paper is loaded and shows the state before paper feeding starts, and FIG. 1-fb) is a structural sectional view when paper is fed. A detailed explanation will be given below using figures.

A large number of sheets of paper 2 are loaded into a paper cassette 3 and inserted into the paper feed port of the apparatus as shown in the figure. At this time, one end of the paper 2 on the side to be inserted into the electrophotographic process is set to be directly below the recording carrier 1. The main paper cassette 3 is held with the paper 2 lifted upward by a spring member 5 via an intermediate plate 6 which is rotatable at one end.

The record carrier 1 rotates at a constant speed of 100 mm/sec, and is surrounded by various units of the electrophotographic process such as Teiden, an optical writing device, a developer, a transfer device, and a remover. Electric appliances, cleaning units, etc. are arranged.

Next, the paper feeding process will be explained. A blank UiF image is formed on the image forming surface of the recording medium 1 by charging and exposure-4, and then toner 10 is attached to the residual image surface ζ by a developing device to perform development. Roughly as the recording carrier 1 rotates, the solenoid 4 operates just before the developing surface reaches the lower part, the cam 18 pushes up the bottom plate 24 inside the paper cassette 3, and the leading edge of the paper 2 comes into contact with the recording carrier 1. At this time, the static electricity generated on the image forming surface of the recording carrier 1 causes the topmost sheet of the paper 2 to disappear! Only the sheet of paper 2 is attracted to one side of the recording carrier and separated from the other sheets 2 as the recording carrier 1 rotates. However, if the frictional force between the sheets is too high or strong static electricity is generated between the sheets, it may be difficult to separate one sheet using only the static electricity of the recording carrier 1. In this case, as shown in the figure, a friction roller 9 is provided behind the static adhering portion of the paper 2 to the recording carrier 1, and the recording carrier 1 of the paper 2 is
A mechanism may be provided in which the friction roller 9 comes into pressure contact with the sheet surface at the same time as the recording medium 1 comes into contact with the recording medium 2 and rotates at the same circumferential speed as the recording medium 1 in the feeding direction of the sheet 2, thereby peeling off the adhesion between the sheets.

The paper l separated in the above manner enters the immediate transfer process 7, where the latent image toner 23 on the recording carrier 1 is transferred to the paper 2, and the paper 2 is separated from the recording carrier 1 by the separation belt 8 and conveyed to the fixing device. be done.

〔Effect of the invention〕

As described above, the paper feeding mechanism according to the present invention is capable of immediately transferring separated sheets without requiring a long conveyance process such as separation, feeding, and transfer as in the conventional method.

Further, since it is possible to store the paper cassette in the apparatus with a straight conveyance process without requiring two stages of conveyance, it is extremely easy to downsize the apparatus.

Furthermore, since the conveyance MA is simple and short, it has the effect of increasing reliability in the case of paper troubles during conveyance, such as paper jams (jams) and skew feeding (skew).

[Brief explanation of the drawing]

Fig. 1 (b) is a structural sectional view of the paper feeding mechanism in the present invention before paper feeding, Fig. 1 (b) is a structural sectional view of the paper feeding mechanism in the present invention during paper feeding, and Fig. 2 is a conventional It is a cross-sectional view of the structure of the paper feeding mechanism. ■...Record carrier 2...Paper!...Top surface of paper 3...Paper cassette 4...Renoid 5...Spring 6...Middle plate 7...Transfer Container 8...Separation belt 9...Hopping roller 10...Toner 11...Developer 12...Charger 13...Optical writing section

Claims (1)

[Claims] In a paper feeding device that separates and feeds sheets of paper one by one from a stacked paper feeding table, the leading edge of the paper in the paper feeding device is placed adjacent to the recording carrier surface, and the sheet is developed by an electrostatic latent image. A paper feeding device characterized in that the leading edge of the paper is brought into contact with the recording carrier surface as the recording carrier surface approaches the recording surface, and the sheets are separated one by one by electrostatic force of the single recording surface.