JPH03152587A - Wet copying machine - Google Patents

Abstract

PURPOSE:To reduce load torque while maintaining sufficient cleaning performance by providing a cleaning unit having a foam roller consisting of a foaming substance and a cleaning blade consisting of an elastic substance and specifying the bite amount of the cleaning blade to a photosensitive body. CONSTITUTION:The machine is provided with the photosensitive body 1 where the latent image of an original image is formed, a developing device 5 by which the latent image is developed, and the cleaning unit 11, which is constituted of the foam roller 25 consisting of the foaming substance and the cleaning blade 26 consisting of the elastic substance, for removing toner remaining on the photosensitive body 1. Then, the bite amount of the cleaning blade 26 to the photosensitive body 1 is set as 1.0-2.0 mm. Thus, the sufficient cleaning performance is maintained even through the bite amount of the cleaning blade 26 is reduced. The load torque is reduced.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a wet type copying machine using a liquid developer.

[Conventional technology]

Conventionally, carrier liquids for developers used in wet-type copying machines (wet-type electrophotographic copying machines) include petroleum-based aliphatic hydrocarbon solvents, such as Isopar E, G, H, L,
KSM (manufactured by Esso Standard Oil Co., Ltd.), Shellzol 71, Turpetz 150 (manufactured by Shell Oil Company), etc.Other carrier liquids include cyclohexane, n-hexane, n-hebutane, n-hexane, -nonane, n-
These include octane, isooctane, isododecane, and ligroin.

To obtain a developer, the colored side, dispersion resin, and other additives are kneaded together with the carrier liquid using a ball mill, a kedimir, or the like to obtain a1M), and this is mixed into an appropriate amount of the carrier liquid. It is enough to disperse it into

When a copying operation is performed using the developer obtained in this way, toner particles in the electrostatic latent image remaining on the photoreceptor without being transferred from the photoreceptor to the transfer paper are removed from the vicinity of the photoreceptor. is removed from the photoreceptor by a cleaning unit located at. In this cleaning unit, a form roller to which developer sucked up from a developer tank is supplied is rotated in sliding contact with a rotating photoreceptor, thereby removing the remaining developer from above the photoreceptor. Further, the cleaning blade of the cleaning unit completely removes the toner from the photoreceptor. The cleaning operation is performed by repeating such steps, that is, by rotating the photoreceptor many times.

[Problem to be solved by the invention]

By the way, when copying is performed using the developer obtained in this way, a serious problem in wet-type copying machines is that toner sticks due to the volatile nature of the petroleum-based aliphatic hydrocarbon solvent. there were. In particular, in order to prevent toner from sticking on a photosensitive drum, which has a particularly bad effect on images, a counter-type cleaning blade has conventionally been used in a cleaning device for a wet-type copying machine. Although this counter type cleaning blade has excellent cleaning performance, it has the disadvantage that the torque of the copying machine body becomes extremely large due to friction with the photoreceptor. In addition, if toner is severely stuck on the photoreceptor, it is necessary to provide a pre-cleaning time before starting the copying operation.

The present invention has been made in view of the problems of the prior art described above, and its purpose is to provide a cleaning blade,
To provide a wet type copying machine which can significantly reduce load torque while maintaining sufficient leaning performance without causing toner sticking even if the biting amount of a form roller is reduced.

[Means to solve the problem]

In order to achieve the above object, the present invention provides a photoreceptor on which a latent image of an original image is formed by exposure, a developer formed by kneading a toner and a low-volatility carrier liquid, and a photoreceptor on which a latent image of a document image is formed. A developing device that develops the formed latent image with the developer, and a cleaning unit that includes a foam roller made of a foam and a cleaning plate made of an elastic material for removing residual toner on the photoreceptor. , the amount of biting of the cleaning blade into the photoconductor is set to 1.
The thickness of the foam roller is set to 0 to 2.0 mm, and the amount of biting of the foam roller into the photoreceptor is set to 0.5 to 2.0 mm.
1. Qmm, and the amount of biting of the cleaning blade into the photoreceptor is 1.0 to 1.0.
2.0 mm, and the form roller has a biting amount of 0.5 to 1.0 mm.

[Effect]

By means of the above means, toner sticking does not occur, sufficient leaning performance can be maintained even if the biting amount of the cleaning blade and the form roller is reduced, and the load torque can be significantly reduced.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. 1st
The figure is an explanatory diagram showing a schematic configuration of a wet-type copying machine according to the present invention.

In FIG. 1, during copying, a photosensitive drum 1 is rotated in a fixed direction by a drive device in the direction of the arrow in the figure, and after being uniformly charged by a charger 2, an original image is projected by an exposure bag W3. to form a latent image. Then, the portion of the photosensitive drum l outside the image area is neutralized by the eraser 4.

The latent image on the photosensitive drum 1 is developed by a developing device 5, and transferred to a transfer paper 7 fed from a paper feeding device (not shown) via a yQ feeding roller 6 as shown by a broken line, by a transfer charger 8.
Transcribed by.

This transfer paper 7 is removed from the photoreceptor drum by a separating roller 9, conveyed by a conveyor belt 10, and then transferred to a fixed position (not shown). After the toner is fixed by the device, it is discharged to the outside. After the transfer paper 7 is separated from the photosensitive drum 1, residual toner is removed by a cleaning unit 11, and residual potential is removed by a static eliminator 12 consisting of a static eliminator lamp or a static eliminator charger, so that the photosensitive drum l is ready for the next copy.

In the developing device 5, a first developing roller 13 and a second roller (1 cola 14) are respectively arranged in the developing container,
Furthermore, a reverse roller 15 is arranged, and the first developing roller 1
3 and the second developing roller 14 are held at a small distance from the surface of the photosensitive drum 1. This interval is adjusted to Q, 1 mm, and the first developing roller 13 and the second developing roller 1
4 is rotationally driven by a drive device in a direction opposite to the photoreceptor drum 1 as shown by an arrow at a peripheral speed faster than that of the photoreceptor drum 1.

The souffle bars 16 and 17 fixed inside the developer container are
The rollers are in contact with the first developing roller 13 and the second developing roller 14, respectively, to constantly clean the toner on the developing rollers.

The developer in the developer tank 19 is supplied by the pump 18 from the developer supply nozzle 21 via the supply pipe 20.
The supplied developer is uniformly conveyed to the surface of the photoreceptor drum 1 by the rotation of the first developing roller 13, the second developing roller 14, and the souffle bar 16. After developing the latent image on the photosensitive drum 1 by flowing between the roller 13 and the second developing roller 14, the developer is removed from the developer recovery hole 22 and the developer recovery pipe 2.
3, it is collected in the developer tank 19 and reused.

The reverse roller 15 is rotationally driven in the opposite direction of the J-shaped photoreceptor drum 1 by a drive device, scrapes off excess developer on the photoreceptor drum 1, and removes the developer on the upper surface of the photoreceptor drum 1 by a souffle lever 24. is scraped off.

The cleaning unit 9 has a sponge-like foam roller 25 that comes into pressure contact with the photoreceptor drum l and a cleaning blade 26 made of an elastic material such as rubber. , the developer is supplied into the cleaning unit 9 from the developer tank 19 via the supply pipe 28. The supplied developer is transferred to a diffusion plate 29 provided below the liquid supply nozzle 27.
This spreads the entire width of the form roller 25. The cleaned residual toner and paper dust are then squeezed out by a squeezing roller 30 along with the liquid, and returned to the developing tank 19 through a collection pipe 32 from a hole 31 at the bottom of the cleaning unit 9.

As the number of times of development increases, the toner concentration in the liquid developer decreases, so this is constantly detected, and if the concentration drops below a predetermined level, toner is replenished into the liquid developer to keep the toner concentration within a predetermined range. It is meant to be kept within.

FIG. 2 is an explanatory diagram showing details of the cleaning unit 9.

In this figure, reference numerals 33 and 34 are solenoids, and the actuating shaft 35 of the noid 33 is connected to a rotating lever 36, and the cleaning blade 26 is attached to the rotating lever 36, which operates the solenoid 33. As a result, the cleaning blade 26 is brought into contact with or separated from the surface of the photoreceptor drum 1. This abutting operation is indicated by a white arrow. Further, the solenoid 34 is operated by the operation shaft 37 of the rotary lever 3 which is interlocked with the operation shaft 37.
A diffusion plate 29 fixedly attached to a rotating lever 39 is brought into and out of contact with the form roller 25 via an angle of 8° 39. This separation motion is indicated by black arrows. Reference numeral 40 denotes a souffle bar, and this souffle bar 40 comes into contact with the squeezing roller 25 to constantly clean the toner on the squeezing roller 25.

In the embodiment described above, the developer pool A accumulated between the photoreceptor drum 1 and the cleaning blade 26 during the copying operation remains on the photoreceptor drum 1 even after the cleaning blade 26 is released by the solenoid 33 after the copying operation is completed. However, in the case of this example, polymethylphenylsiloxane is used as the carrier liquid, and even when the copying operation is started after being left for a long period of time, this developer is starting point and the top of the image)
The fixed toner on the photosensitive drum 1 is cleaned by passing through the cleaning device once. That is, a portion of the fixed toner generated from the developer pool caused by the first developing roller 13 on the photosensitive drum 1 is transferred to the cleaning blade 26.
If the photoreceptor drum 1 passes through, cleaning has been completed completely, and in the pre-cleaning operation, exposure is started before the photosensitive drum 1 rotates once, and a copying operation is performed. Therefore, the leading edge of the virtual image is set at the first rotation of the photosensitive drum 1 during the pre-cleaning operation.

The developer uses a low-volatility carrier liquid as its carrier liquid. A substance having a siloxane structure, such as polymethylphenylsiloxane, is used as the low-volatility carrier liquid.

A mixed solution of 50% by volume of T 5opar H and 50% by volume of polymethylphenylsiloxane was used as the carrier liquid in the example.

Comparative example T5oparH was used as a carrier liquid.

First, on each side, reduce the amount of bite of the form roller by 1.
．． 5, 1.0, and 0.5.0 mm (cleaning blade depth fixed at 2.5 mm), "small dirt", "required number of cleaning times", and "filing condition" were measured. The results are shown in Figure 3.

Note that small stains are caused by a mist of developer sprayed downward from the form roller and deposited in spots on the transfer paper.
This is expressed in five stages (5: excellent, 3: acceptable level). In addition, the number of times of cleaning required for each carrier liquid is as follows:
After running 5,000 sheets under each condition using a developer containing 100 g/l'iB of toner for 5085, I left it for a week until the toner on the photoreceptor drum could be cleaned. This is the number of times the virtual image leading edge passes through the cleaning unit. Further, the filming state was O: not observed at all.

Δ: Slightly acceptable, etc. is rated 7.

As is clear from FIG. 3, in the conventional example, if the amount of biting of the foam roller was reduced, the small dirt was improved, but the number of times of cleaning required increased, and filming was slightly observed over the entire area.

On the other hand, in the embodiment, the amount of indentation of the form roller is preferably 0.5 to 1.0 mm in consideration of the rank of small dirt particles.

Next, in the conventional example and the embodiment, the biting depth of the cleaning blade is 2.5.2.0.1.5.1, 0.
FIG. 4 shows the results of measuring the "load torque", "required number of cleaning times", and "black streak level" when the thickness was set to 0.5 mm (foam roller bite was fixed at 1.5 mm).

The black stripe level is an evaluation of the black stripe level of the photoreceptor drum after running 50,000 sheets.
: Ring streaks are clearly observed, Δ: Ring streaks are slightly observed, 0: Ring streaks are not observed at all.

As is clear from Fig. 7PJ4, in the conventional example, when the amount of biting of the cleaning blade is reduced, although the load torque is reduced, the number of times of cleaning required increases, and ring streaks cannot be eliminated.

On the other hand, in the embodiment, it is desirable that the cleaning blade bite is 1.0 mm or more in terms of the number of cleanings required, and 2.0 mm or less in terms of the black streak level, and the load torque is also lower than that of the conventional example. can be reduced by

〔Effect of the invention〕

As explained above, even if the amount of biting of the cleaning blade and the form roller is reduced, toner sticking will not occur and the load torque can be significantly reduced while maintaining the cleaning performance.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the schematic configuration of a wet copying machine, Fig. 2 is an explanatory diagram showing details of the cleaning device, and Figs. 3 and 4.
The figure shows the measurement results. l......Photoreceptor drum, 5...
...Development device, 8...Transfer device, 11.
......Cleaning unit, 25...
...Four 110-ra, 26...
cleaning blade. Figure 2 Figure 3 Figure 4

Claims (3)

[Claims] (1) A photoreceptor on which a latent image of a document image is formed by exposure, a developer obtained by kneading toner and a low-volatility carrier liquid, and a developer that forms a latent image of an original image on the photoreceptor; a cleaning unit having a foam roller made of foam and a cleaning plate made of an elastic material for removing residual toner on the photoreceptor; A wet type copying machine characterized by having a biting amount of 1.0 to 2.0 mm. (2) A photoconductor on which a latent image of an original image is formed by exposure, a developer obtained by kneading toner and a low-volatility carrier liquid, and a developer that forms a latent image of the original image on the photoconductor; a cleaning unit having a foam roller made of foam and a cleaning plate made of an elastic material for removing residual toner on the photoreceptor; A wet-type copying machine characterized by having a biting amount of 0.5 to 1.0 mm. (3) A photoreceptor on which a latent image of a document image is formed by exposure, a developer obtained by kneading toner and a low-volatility carrier liquid, and a developer that forms a latent image of the original image on the photoreceptor; a cleaning unit having a foam roller made of foam and a cleaning plate made of an elastic material for removing residual toner on the photoreceptor; A wet-type copying machine characterized in that a biting amount of the foam roller is 1.0 to 2.0 mm, and a biting amount of the foam roller is 0.5 to 1.0 mm.