JPS5940674A - Transferring device of copying machine - Google Patents

Abstract

PURPOSE:To secure an excellent transfer image, by providing a thickness detecting means which detects the thickness of a form prior to transferring operation and a transfer current controlling means which set the transfer current of a corona discharger according to the detected thickness. CONSTITUTION:A thickness detection roll 15 arranged at the lower side is driven as shown by an arrow to rotate, and a detection roll 16 arranged at the upper part has its rotating shaft 17 supported pivotally at one end of a displacement measuring plate 18. The displacement measuring plate 18 is arranged rotatably around a rotating shaft 19 fitted to its other terminal, and the circumferential surface of the thickness detection roll 16 is pressed by a spring 21 against the circumferential surface of the other detection roll 15. The shaft 19 is supported pivotally at both ends by metallic fittings 23 and 24 provided to a fixed plate 22 fixed slightly above a form conveyance path 14, and the detection contactor 251 of a displacement sensor 25 contacts the end surface of the displacement measuring plate 18 on the side where the rotating shaft 17 is fitted.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transfer device for a copying machine that transfers a 1-toner image formed on a photosensitive material by development onto a sheet of paper.

In an electrostatic copying machine, an electrostatic latent image corresponding to an original is formed on a sensitive material, and this is developed with 1 to 2 to form a dove image. To transfer this I-toner image onto paper, a transfer device using a corrope transfer method is generally used. In this device, a discharge electrode is used.
-A charge of the opposite polarity to that of the toner is applied to the back surface of the paper for transfer, and the toner image is transferred to the surface of the paper.

A traditional transfer device like this? 1, the current flowing through the discharge electrode II 1-1 (hereinafter referred to as transfer current) was set to a predetermined current value. This current value is a value C at which the paper normally used is suitable for the photosensitive material and has the best transfer efficiency.

However, as the types of paper used in copying machines have become more diverse, there has recently been an increase in the number of copies made on thick paper for official postcards. When copying is performed on such particularly thick paper, the transfer efficiency of the transfer device decreases, and there is a tendency that a good copy image cannot be obtained with the conventionally set transfer current. In other words, if thick paper is used, the adhesion of the paper to the photosensitive material will be weakened, and the gap between the photosensitive material and the paper (
・The deviation is 51 ilg-! There is something called J. In this case, partial disturbances (violets) occurred in the copied image. The solution to this problem is to set the transfer current to a normal value. However, in this case, not only was the transfer efficiency lowered compared to ordinary paper, but the paper also adhered firmly to the photosensitive material, making it difficult to peel it off. In addition, even if the paper can be peeled off from A in this condition, undesirable phenomena such as particles scattering (blur) may occur when the paper is peeled off, which may deteriorate the image quality. It became.

In view of the above circumstances, an object of the present invention is to provide a multi-layer transfer device capable of ensuring good transfer of a 1-no image regardless of the thickness of the paper. Do Juru.

In the present invention, the transfer device is equipped with a detection means for detecting the thickness of the paper onto which the toner image is transferred, and a transfer current control means for changing the transfer current according to the detected p thickness,
Achieve the first goal mentioned above.

The present invention will now be described in detail with reference to a two-handed embodiment.

FIG. 1 shows the main parts of a copying machine capable of controlling transfer current. This copier uses exposure lamp 1.
is placed on a platen (not shown). I irradiated draft 2, and it turned out like a sea urchin. The optical image of JJi', Sugi 2 is
The light is exposed to exposure position A on the C1 photosensitive drum through the first mirror 3, the optical lens 4, and the second mirror 5. -1j, a charger discharger 7 discharges electricity to a photoreceptor drum 6 which rotates in the direction of the arrow;
This is uniformly charged to, for example, -U. As a result, an electrostatic latent image corresponding to the original 2 is formed in exposure A)'/A. The electrostatic W image is created in the current WA device 8 by
During development, a toner image is formed. 1 to No images follow the rotation of the photoreceptor drum l\6 (, the transfer roller
-1) Move to the transfer position 1d13 facing the discharger 9,
Here (') will be transferred onto paper 11.

By the way, f! on paper feed l/ray 12! IV4 paper 11
is sent to the paper conveyance path 14 by the feed roller 1 at the timing when the 1-toner image is transferred by the transfer position movement B. A pair of thickness detection rollers 15 and 16 are arranged in the paper conveyance path 14 near the feed line 13.

FIG. 2 shows a storage space detection mechanism using these feeders [1-ra 15 and 16]. Thickness detection unit 15 arranged on the upper side is driven to rotate in the direction of the arrow by a drive system (not shown). The upper roller detection roller 16 has its rotating shaft 17 supported by one end of a displacement measuring plate 18 .

The protrusion measurement root 18 is arranged at the other end so as to be rotatable around a rotating shaft 19 which is cut by a spring 21.
Thickness detection [1-The circumferential surface of the roller 16 is brought into contact with that of the other roller 15.

The shaft 19 is pivotally supported at both ends by a pair of metal fittings 23 and 24 attached to a fixed portion 22 fixed slightly above the paper conveyance path 14. A displacement hinge is provided on the upper surface of the end of the displacement measurement member 18 on the one-digit side of the rotating shaft 17.
25 detection contacts 251 are in contact.

Figure 3 shows an example of the epidemiological position sensor.

This displacement sensor →) 25 has a detection contact 251 attached to one end of an elastic piece 252, and the other end is fixed to a frame or the like (not shown) with a fixing fitting 253.

elasticity)"+' 2 b 2 is S i Cengage 254
is taken (=J [pull. The sensor gauge 254 outputs the change in IQ of the detection contact 251 in the direction of the arrow as a change in resistance value). Displacement i? It is best to use the electric microcontroller (another sensor 1).

Now, the paper 11 sent out to the paper transport path 14 passes between a pair of thickness detection []-ra 15 and 16. At this time, the displacement sensor 9-25) outputs a displacement display signal 27 representing the thickness of the paper 11 by a resistance value or the like. Displacement display signal 2
7 is supplied to a transfer current control circuit 28.

FIG. 4 shows a total of six transfer current control circuits. The displacement display signal 27 is amplified by a signal processor 281 and further converted into a digital signal. If the resistance value is manually generated, the amplification is performed after it is converted into a current value or a voltage value.
be exposed. The digital displacement signal 29 obtained by this
is supplied to the sheet 282, and its I/H state is maintained by the recording control signal 31 supplied from the timing controller 283 at the timing when the displacement of the paper 11 is being measured. Digital displacement signal 32 output from latch 282 is provided to read-only memory 284 as address information.

The second figure shows the relationship between the Jν of the paper onto which the J-toner image is transferred and the transfer current q'.
showed the optimal transfer characteristics, and the two
Region I surrounded by two curves 34.35! In the region C where iIE is transferred to the paper, smearing occurs due to insufficient transfer current and transfer efficiency decreases.

In the 7C region [), excessive transfer current causes ribbler with poor peeling, and the transfer efficiency similarly decreases. A read-only memory 284 receives a digital displacement signal 32 related to the thickness of the paper and a curve 33.
The transfer current ratio calculated in advance based on is outputted as a digital current signal 36. For example, normal paper has a thickness of about 100 .mu.l, and this copying machine outputs a current of about 40 .mu.A (1'J) as the digital current signal 36.

In addition, in the case of official postcards, the thickness of the letter is approximately 230flI.
11, and a current value of approximately 60 uA is output as a digital current signal 36. The digital current signal 36 is supplied to a control signal generator 285, and a control signal 37 for setting a desired transfer current is generated.

The control i11 signal 37 is supplied to the ψl:Shagawa High 1 power supply 38, and in this case, an ideal current with the polarity of ■ is set. Therefore, when the paper 11 passes through the head 13 at the 21' position, the transfer of the dove image is performed well. -F direction.3 RJ 71 Bundenki 39 is connected to AC high voltage power supply 41, A3S, Paper 1
1 peeling is performed. Since the paper 11 is attached to the photosensitive drum 6 with excessive pressure, the paper 11 is peeled off well, and the transferred 1 to 3 images are not disturbed.

After that, the paper 11 further advances through the paper conveyance path 14, and after being fixed by a fixing mechanism (not shown), it is ejected onto a tray (as shown in the figure) by a pair of output rollers 42 and 43. Ru.

In this embodiment, CiI! /i′
We avoided changing the current value of the corona discharger for 4′, but when using the][1] corona discharger for peeling, the current value of this][1] corona discharger should be changed according to the 1ν of the paper. It is equally effective to change the situation.

1-Explained: According to the present invention, the transfer current is transferred to the paper 1! ? There is an advantage that the range of options that can be selected varies depending on the paper size (because it is set to 1-1, the range of paper to be copied from 1 to 1) is widened.

[Brief explanation of the drawing]

Fig. 11 is a schematic diagram of a copying machine according to an embodiment of the present invention, and Fig. 2 shows a thickness detector 41 of the transfer device of this copying machine.
4 is a block diagram of the transfer current control circuit, and FIG. 5 is a block diagram of the transfer current control circuit, and FIG. This is a characteristic diagram based on the relationship. 6...Photoconductor drum 9.39...'' Lob discharger 11...Paper 15, '16...19 Detection CI-ra 2b...
...Displacement sensor 1) 28...Transfer current control circuit η drop 7L Fig. 4 ″ 65

Claims (1)

[Scope of Claims] 1. A corona f+Q electric device that applies a 11i electric current from the side of the paper in order to transfer the toner image formed on the paper to the paper, and +'+ii the thickness of the paper. Thickness detection means that detects the thickness prior to the transfer operation, and the thickness detection means that detects the thickness according to the detected thickness
1. A transfer device for a copying machine, comprising: a transfer g number control means for setting and controlling a transfer current of a Robb lIi lightning device. 2. The present invention is characterized by comprising a current control means for setting a current 11C1 of a discharger for peeling the paper from the photosensitive material in accordance with the temperature detected by the temperature detection means. A transfer device for a copying machine according to claim 1.