JPS6026968A - Copying apparatus - Google Patents

Abstract

PURPOSE:To prevent paper sheets from humidity and to lower cost by using the fixing roller of a fixing device for fixing a toner image transferred to said sheets with a heat fixing roller, also as a paper feed roller for feeding the sheets into a copying apparatus. CONSTITUTION:The electrostatic latent image of an original formed on a photosensitive drum 8 is transferred to a dielectric belt 18 located opposite to the drum 8 by cooperation of a transfer roller 17. The latent image transferred to the belt 18 is developed with a developing device 3. A sheet 1a is conveyed between a heater roller 22 and a backup roller 16, and the toner image on the belt 18 is heat pressed and simultaneously transferred and fixed to the sheet 1a. It is ejected with a paper ejection roller 20 to a paper ejection tray 21. The backup roller 16 is used for 2 functions as a feed roller for feeding the sheet 1a out of a cassette 1 and as a pressure roller for transferring and fixing the toner image by this structure, and heat for fixing can also be used for dehumidifying the sheets, thus permitting prevention of the sheets from humidity and reduction of cost.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a heat fixing device such as a copying device, and more particularly to a copying device in which a single call of heat fixing used in the fixing device is also used as a paper feed roll.

[Prior art]

Conventionally, the paper sheets fed into a copying apparatus are largely dependent on the humidity of the room in which the copying apparatus is installed, and when they absorb moisture, they have the disadvantage of significantly deteriorating copy quality.

In order to eliminate such problems, a copying apparatus has been known in which a dehumidifying heater is disposed below the paper feed line as shown in FIG.

FIG. 1 is a side view of the main parts of a conventional copying machine equipped with a dehumidifying heater. A charger 10 for uniformly charging the surface of the photosensitive drum 8 is disposed to face the photosensitive drum 8.

The charger 10 is required to form an electrostatic latent image on the surface of the photosensitive drum 8 corresponding to the pattern of the document on the document table 12 projected through the optical system 9.

Furthermore, a developing device 3. converts the electrostatic latent image formed on the surface of the photosensitive drum 8 into a visible image. The visible image on the photosensitive drum is
a transfer electrode 45 for transferring the paper sheet 1a to the photosensitive drum 8; a separation electrode 5 for separating the paper sheet 1a from the photosensitive drum 8; The photosensitive drum 8 is surrounded by a +U conveying belt 6 that conveys the sheet 1a separated by the separation electrode 5 toward the fixing roll 7 for thermal fixing, a cleaner device 11 that cleans the toner adhering to the photosensitive drum 8, and the like. will be placed in On the other hand, a paper feed roller 2 and a guide plate 14 are provided as means for feeding the paper sheets 1a stacked on the force set 1 between the photosensitive tram 8 and the transfer electrode 4.

When the developed image on the photosensitive drum 8 is transferred to the paper sheet 1a by the corona discharge of the transfer electrode 4, the moisture absorption level of the paper sheet 1a greatly affects the transferred image quality. Near 4 minutes.

In FIG. 1, a dehumidifying heater 13 is disposed at the lower end of the guide plate 14 to take a moisture-proofing measure by preheating the sheet onto which the image is to be transferred.

[Problems with conventional technology]

In the case of the configuration described in Section 2, the paper sheets 1a in the cassette 1 set in the copying machine are also heated.

Although it exhibits a dehumidifying effect to some extent, if cassettes of other sizes that are not set in the main body of the copying machine have been left under high humidity, if this cassette I~ is replaced with the main body, the dehumidifier 13 will Unless the capacity is greatly increased, the paper sheets 1a in the replaced cassette cannot be completely dehumidified. In general, in thermal fixing type copying machines, it is difficult to significantly increase the dehumidifying heater capacity due to the power supply capacity used, and even if a high capacity heater is used, it is not efficient.
− It had the disadvantage that it was difficult to dehumidify it.

[Purpose of the invention]

The present invention was made in view of the above drawbacks, and its purpose is to dehumidify the fuser roll using a heater built into the fixing roll without using a special dehumidifying heater, and to also serve as both the fixing roll and paper feed roll. It is an object of the present invention to provide a copying apparatus which reduces the number of parts by reducing the number of parts.

[Key points of the invention]

In order to achieve the above object, the present invention provides a fixing device that uses a heat fixing roll to fix a toner image transferred to a paper sheet. It is characterized in that it also serves as a paper feed roll for feeding paper into a copying machine.

[Embodiments of the invention]

Two embodiments of the present invention will be described in detail below with reference to FIGS. 2 and 3.

FIG. 2 is a side view of the main parts of the copying apparatus, and FIG. 3 is an enlarged side view of the paper feed section shown in FIG.

4- The same parts as in Fig. 1 are given the same reference numerals and redundant explanations are omitted.5 The copying machine shown in Fig. 2 uses electrostatic transfer and pressure-thermal transfer fixing methods, The pattern of the document placed on the photosensitive drum 8 is formed as an electrostatic latent image on the photosensitive drum 8 via the optical system 9. The electrostatic latent image formed on the photosensitive drum 8 is transferred onto a dielectric bell 118 disposed facing the photosensitive drum 8 in cooperation with the transfer roller 17 . The above-mentioned dielectric bell l-18, guide roller 24°, heater roller 22. Guide roller 24. It is an endless belt that surrounds the outer periphery of the transfer roller 17.

It is rotationally driven by these rollers. The latent image transferred onto the dielectric heald 18 is visualized by the developing device 3. A sheet of paper 1a is conveyed between the heater roller 22 and the hack-up roller 16, and the toner image on the dielectric belt is
Simultaneous pressure and heat transfer and fixation are performed on a. On the other hand, the paper sheet 1a stored in the paper cassette 1 is biased upward by the paper feed lever 15 during paper feeding, and the uppermost paper sheet 1 stacked in the cassette 1 is
a is adapted to come into contact with the backup roller 16.

The hack-up roller 16 starts rotating in response to a command signal to start copying, and the paper sheet 1a is moved from the cassette l to between the guide plates 25 and 25, between the standby rollers 27 and 27, and then between the guide plates 26 and 26, as shown in FIG. is fed between the heater roller 22 and the bank up roller 16 along the dielectric bell 118. Of course, in this state, the paper sheets 1a are not continuously fed from the cassette 1. That is, the uppermost paper sheet 1a stored in the cassette 1 is transferred to the backup roller 1.
The paper sheet 1a in the cassette 1, which had been biased upward by the paper feed lever 15 before leaving the cassette 6, has its biasing force released and the contact between the backup roller 16 and the uppermost sheet 1a is broken. It is now possible to Therefore, even if the backup roller 16 is rotating for a purpose other than feeding paper, the paper sheets 1a in the cassette 1 will be moved by the guide plate 25 as long as there is no copy command signal.
Paper is not fed continuously in 25 directions.

The paper sheet 1a that has been pressure-thermal transfer-fixed by the backup roller 16 and the heater roller 22 is discharged by the paper discharge roller 6-20.

Incidentally, in FIG. 2, reference numeral 19 denotes a static elimination electrode that eliminates the electric charge on the photosensitive drum.

In the second embodiment, a copying machine using a dielectric hel 1-18 for electrostatic transfer and pressure transfer fixing was described, but as shown in Fig. It is also possible to apply the invention.

In other words, in FIG. 4, the sheet 1 fed from the case 1-1. Guide lI Fj, between 25.25 - standby roller 27
．． 27 and the guide plate 26. After the image developed on the outer periphery of the photosensitive drum 8 is transferred onto the paper sheet 1a by the transfer electrode 4, the paper sheet 1a is fed to the transfer section through the guide plate 28. 22 and the backup roller 16, the paper is heated under pressure and fixed, and then the paper is transferred to the discharge tray 2.
The paper sheet 1a may be discharged at the same time as the paper sheet 1a.

According to the present invention, since the hack-up 1 cola 16 is configured in a diagonal manner, it can serve two functions: as a pressure roller for feeding the sheet 1a in the cassette 1 and for transferring and fixing the 1-ner image. I can do it.

Furthermore, in the case of FIG. 3, the hack-up l cola 16 is normally in a heated state through the dielectric heald 18, and in the case of FIG. When used, it can be used to dry and dehumidify the paper sheet 1a. By selecting a material such as silicone rubber for the backup roller 16, it can be constructed to withstand high temperatures, and at the same time, it is possible to provide good paper feeding.

Further, more stable copies can be obtained by controlling the temperature of the backup roller 16 by providing a separation means for releasing the pressure contact with the dielectric heald 1B or the heater roller 22 except during transfer and fixing. Furthermore, in the embodiment described above, even if toner remains on the dielectric belt 18 or the heater roller 22 during transfer and fixing, a small amount of the remaining toner adheres to the back side of the paper sheet 1a via the hack-up roller 16. The transfer surface of the sheet 1a is not contaminated, and the sheet 1a is always preheated by heat supplied from the large-capacity fixing heater roller 22 before entering the fixing process, so thermal fixing properties are significantly improved. Effects such as doing.

〔Effect of the invention〕

As described above in detail, according to the copying apparatus of the present invention, the fixing roll and the paper feed roll are also used as -U-, so the heat for fixing can also be used to dehumidify the paper sheets. It is possible to prevent deterioration of image quality due to moisture absorption.

Further, by using the above-mentioned parts, it is possible to reduce costs, which has a great effect.

[Brief explanation of the drawing]

FIG. 1 is a side view of the main parts of a conventional copying machine. FIG. 2 is a side view of the principal parts of the copying apparatus of the present invention. FIG. 3 is an enlarged route map of the vicinity of the fixing heater roller and hack-up roller in FIG. 2, and FIG. 4 is an enlarged route map similar to FIG. 3 of another embodiment of the present invention. 1...Cassette, 2...Paper feed roller. 3...Developer, 4...Transfer electrode. 5... Separation electrode, 6... fill feeding heald. 7... Fixing roll, 8... Photosensitive tram. 9... Optical system, 10... Charger. =9- 11... Cleaner device, 12... Document table, 13
...Dehumidifying heater, 14゜25.26.28...Guide plate, 15..., Il lever, 16...Backup roller, 17...Transfer roller, 18...Dielectric heald, 19...・Static elimination electrode. 20... paper ejection roller, 21... paper ejection tray, 2
2... Heater roller. 23...Developing roller, 24...Guiding roller,
27...Standby roller patent applicant Casio Computer Co., Ltd. Same as above Yoshiyuki Osuga, agent patent attorney for I.D. Co., Ltd. -10= Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] (1) In a fixing device that uses a heat fixing roll to fix toner images transferred to paper sheets, the heat fixing roll is used to feed the paper sheets into the copying device. A copying device characterized in that it also serves as a paper feed roll.