JPS62138862A - Copying device - Google Patents

Abstract

PURPOSE:To eliminate a defect in transfer by providing an air flow passage which crosses a transfer paper conveyance path between a photosensitive body and a fixing device, providing on air flow generating means on the transfer surface side of transfer paper, and providing a transfer paper conveyance guide which does not impedes a flow of air above the part of a transfer paper passage which crosses the air flow passage. CONSTITUTION:Ducts 11 and 12 are connected to the discharge port of a fan 10-1 and wind around the fixing device 13 so as to flow air out of a machine from the upper part to the rear part of the fixing device. An air curtain is therefore formed between the fixing device 13 and a process unit 2 to prevent heat generated by a fixing roller from being conducted to the process unit. The air discharge ducts 11 and 12 and the path for transfer paper cross each other, so the ducts are narrowed down in opening sectional area as the transfer paper is conveyed from a transfer part to a fixing part and closed until it finishes passing. At this time, the air from the fan 10-1 is blown out of the machine by providing a louver 11-1 which is open to the outside to the upstream- side duct 11.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a copying apparatus that transfers and fixes a toner image with the image side facing down.

Conventional technology As one of the means to downsize the copying machine, the loading charger is also used as the total transfer charger, and the toner image is transferred to the lower surface of the transfer paper on the upper side of the photoreceptor belt, and the transfer paper is transferred to the fixing device in this position. 2 cycles 1 to transport and complete fixing
Copying machines for copying systems are known. In this type of copying machine, the underside of the transfer paper carries an unfixed toner image while being conveyed, so if the underside of the transfer paper is moved with a normal guide member, problems such as image blurring may occur. .

In addition, in such a small copying machine, heat from the fixing device is easily transmitted to the process unit that houses the photoreceptor, and there is a risk that the process unit may completely change its characteristics due to the heat.

Purpose: In view of the above-mentioned facts, the present invention aims to completely prevent rijjj image distortion during the conveyance process of a transfer paper carrying an unfixed toner image in a copying apparatus that forms an image with the image side facing down. Another object of the present invention is to provide a copying apparatus in which heat from a fixing device is prevented from being transmitted to a process unit that holds a photoreceptor as much as possible.

Structure In order to achieve the above object, the present invention provides a copying apparatus that transfers a toner image from a photoreceptor to the lower surface of a transfer paper, conveys the transfer paper in that position to a fixing device, and performs fixing. An air flow path that intersects with the transfer paper conveyance path is provided between the transfer paper path, an air flow generation means is provided on the transfer surface side of the transfer paper, and an air flow is provided above the portion of the transfer paper path that intersects with the air flow path. It is characterized by the provision of a transfer paper transport guide that does not obstruct the transfer paper at all.

By providing an opening such as a louver that communicates with the outside air on the upstream side of the transfer paper path in the air flow path, when the air flow path is blocked by the transfer paper, the air flow can escape to the outside air and be transferred to other parts P.
C all the evil effects, fullwi.

It also prevents flapping when the air flow generation means is stopped, and easily replaces all the air in the air flow path heated by the heat of the fixing device, making it easier to cool the fixing device. In addition, it is possible to make it difficult for the heat of the fixing device to be transmitted to the process unit VC including the photoreceptor.

Hereinafter, embodiments of the present invention will be explained in detail based on the drawings.

FIG. 1 is a diagram illustrating the implementation of the present invention. Copy machine body 1
Inside, a process unit 2 including a photoreceptor belt, a developing device, and a cleaning device is removably provided. Inside the process unit 2, an endless belt-shaped photoreceptor 2-1 is supported by a driving roller 2-2 and a driven roller 2-3, and is provided so as to be rotatable in the direction of the arrow. A developing roller 2-4 is provided on the lower surface side of the lower run of the photoreceptor belt 2-1 so as to rotate in the direction of the arrow in contact with the belt, and the developing roller 2-4 has a developer storage chamber. The developer in 2-7 is replenished by the replenishment roller 2-6, and a thin developer layer V is formed by the developing blade 2-5. An agitator 2-8 is provided in the developer storage chamber 2-7 and rotates in the direction of the arrow to agitate the developer. Photoreceptor belt 2
A cleaning blade 2-9 is provided on the outer surface of the portion wrapped around the driven roller 2-1 so as to be able to approach and separate from the outer surface of the photoreceptor belt by a solenoid (not shown). moreover,
A chamber 2-10 is provided at the bottom of the blade 2-9 to collect the developer collected from the photoreceptor during cleaning. This chamber and the developer storage chamber 2-7 are connected to the developer transport path 2-1.
] are connected. Developer conveyance path 2-111/koha,
Foreign matter such as paper powder mixed into the collected developer? f: Purpose of removal and handling of process unit 2 externally 1[3,
In order to completely prevent the developer from flowing back from the storage chamber 2-7 into the collection chamber 2-10 and becoming dirty, a brush-like or thin film-like valve member 2-12 is lightly contacted with the bottom surface VC of the conveyance path 2-11. It is provided. Further, as shown in the figure, the bottom surface of the conveyance path 2-11 has a substantially semicircular vertical cross section, and a magnet 2-14 is provided on the outside thereof to rotate in the direction V of the arrow about the entire center of the shaft 2-13. As a result, the developer collected in the collection chamber VC is conveyed to the storage chamber 2-7 and reused.

The process unit 2 can be inserted from the right side of the main body 1 of the copying machine 1 in FIG. As shown in Figure 2, the process unit has a lid 2-1 on the left half of the top surface.
A protrusion 2-16 is provided on the left end of i2-15, and the lid 2-15'ff cannot be inserted into the main body when closed. Therefore, as shown in FIG. 1, the process unit 2 is opened and inserted into the main body of the copying machine, with the right half of the top plate stacked on top of the top plate, and is mounted in a predetermined position.

Process Unison) k With the main body VC attached, the exposure section and charging/transfer charger 9 are connected to the photoreceptor belt 2-1 through the opening of the one-piece unit, facing the ground running portion of the photoreceptor belt 2-1. 1 and maintains a predetermined relative position. In this embodiment, a roof mirror lens array (RMLA) 3 is used in the exposure optical system for miniaturization, and the reflected light from the original illuminated by the light source lamp 4 is passed through the photoreceptor belt 2 to the RMLA. Two images of the outer surface of the portion wound around the drive roller 2-2 of 1 are imaged and slit exposure is performed. As in conventional copying machines of this type and similar, the original is held between an original platen glass 5, an original pressure plate 6, and a VC, and is scanned by a lever that moves from side to side. The pressure plate 6 is attached to the shaft 6- on the right end of the figure.
It can be opened and opened using 1 as the center of rotation. A sheet feed roller 6-2 is provided on the shaft 6-1, and a backup roller 6-3 is provided in contact with the sheet feed roller 6-2.
A mouth 6-4 is formed. Above the process unit 2, a paper feeding roller 7, a registration roller 8, and the aforementioned charging/transfer charger 9 are arranged in the main body of the copying machine. The left side of the main body (llv) is provided with a drive motor 10,
A fan 10-1 is attached to the shaft opposite to the movable output shaft. This allows the fan 1 to operate at the same time as the main unit.
Air is blown by 0-1. Drive motor 10 and fan 10. A heat roller fixing device 13 is provided at the upper right of the photoreceptor belt 2 of the process unit 2.
A toner image is transferred to the lower surface at the transfer section between the transfer sheet 1 and the transfer charger 9, and the ejected transfer sheet advances straight and enters the nip of the fixing device 13.

This type of copying machine has 1 process unit 2 and a fixing device 1.
The distance from 3 is not a light separation. Therefore, with this device,
A duct connected to the outlet of the fan 10-1) 11.
12 is provided so as to surround the fixing device 13 and exhaust air from the top of the fixing device toward the rear to the outside of the machine. Therefore, an air curtain is formed between the fixing device 13 and the process unit 2, and the heat generated from the fixing roller is prevented from being transmitted to the process unit.

Since the ventilation duct (I), 12 intersects with the path of the transfer paper, as the transfer paper is conveyed from the transfer section to the transfer section, the opening cross-sectional area of the duct becomes narrower, and the duct is closed until it has finished passing through. Ru. At this time, in order to release the airflow from the 77-channel 10-1 to the outside of the machine, a root cooler 11-1 that is open to the outside world is provided in the duct 11 on the upstream side of the transfer paper path. Furthermore, conveyance lips 12-1 are provided in a grid pattern above the transfer paper path passing through the ducts 11 and 12. Therefore, when the transfer paper does not cross the duct, the airflow flows through the ducts 11, 12 and is discharged outside the machine, sufficiently blocking heat. Even when copying is completed and the fan 10-1 is stopped, if the fixing device 13 has heat, the air inside the duct is warmed, and outside air is drawn from the root cooler 11-1 and out of the machine through the entire duct 12. It is effective in cooling the fixing device and stopping heat transfer to the process unit.

Next, to explain the copying operation, when a copy start button (not shown) is pressed, the photoreceptor belt 2-1 moves in the direction of the arrow V.
This rotates. At this time, the slider made up of the original glass plate 5 and the pressure plate 6 moves from the center position to the right end, and then moves to the left again, and at this time exposure scanning is performed.

The transfer paper inserted into the transfer paper insertion slot 6-4 is sent out by rollers 6-1 and 6-3, as will be described in detail later, and its tip is passed through the registration roller 8 by the intake roller 7V of the main body.
It is sent until it stops. By the time the slider moves to the right end, the transfer paper is separated from the rollers 6-1, 6-3 and held by the drawing roller 7.

The copy processing is a known 2-cycle 1-copy system in which a photoreceptor belt 2 is uniformly charged by a charger 9.
-1 is exposed to light to form a latent image, and the developing roller 2-
4, a toner image is formed, and an open toner image of a cleaning blade retracted from the surface of the photoreceptor passes through a solenoid (not shown) and reaches the charger 9 again. At the same time, a toner image is transferred to the lower surface of the transfer paper fed by the registration roller 8 by the charger 9 which acts as a transfer charger, and the curvature radius of the drive roller 2-2 and
The transfer paper separated from the photoreceptor belt 2-1 by the width of the paper 11 crosses the duct 11 and heads toward the fixing device 13. Since the wind is blowing from the bottom to the top of duct 1, the top surface of the transfer paper slides against the conveyance rib due to the wind pressure, so there is no need to guide the entire bottom surface of the transfer paper.
There is no possibility of image distortion occurring. Also, as shown in Figure 4, when the transfer paper does not cut off the flow path of the wind, the streamline A is
As the transfer paper moves through the flow path, the flow of the wind passes through the louver 11-1'ii, flows along the streamline B, and is discharged outside the machine, causing the wind to blow into the transfer section. can avoid.

Also, as shown in Figure 5, a damper type valve is installed in the duct 1.
5 is provided, the opening degree is changed as the transfer paper enters the duct]1, and the valve 15 is controlled to close completely when the transfer paper completely covers the duct]1. is A
It gradually changes from B to B, and it is possible to prevent problems such as poor transfer and scattering of developer caused by flapping of the transfer paper due to wind at the transfer section.

After the transfer is completed, the photoreceptor belt 2-1 comes into contact with the developing roller again, but by changing the developing bias, the reproduction of the image is prevented and a cleaning action can be performed, and the belt is completely cleaned by the next cleaning blade. Since the recovered toner is completely reused, the space required for the recovery tank can be reduced, and there is no need to detect when the recovery tank is full.

To explain the transfer sheet insertion mechanism with reference to FIG. 3, the fixed shaft 6-1 provided at the rear end of the document platen glass 5 is the opening/closing center of the pressure plate 6, as well as the center of the sheet conveyance roller 6-2. Torsion spring 6-5 inside -y
J k @h 61 is provided with the other end fixed to the inner circumferential surface of the roller 6-2. The slider is reciprocated using a rack and pinion system. A pulley portion 6-6 having a smaller diameter than the roller outer diameter is provided at one end of the roller 6-2, and a wire 6-7 is fixed with one end wrapped around the main body and the other end wrapped around a portion of the pulley.

In FIG. 1, when the user inserts the transfer sheet between the roller 6-2 and the backup roller 6-3 and presses the print start button, the slider starts moving completely to the right. At this time, the roller 6-2 is rotated clockwise by the wire 6-7 against the torsion spring 6-5. This results in
The roll 7 sheet is sent to the main body drawing roller 7. The feed speed at this time is configured to be 92 times the moving speed of the slider based on the difference VC between the diameters of the roller 6-2 and the pulley portion 6-6. Therefore, by the time the slider reaches the right end, the trailing edge roller 6-
2. When the slider reaches the left end, which is off from 6-3,
The wire 6-7 is wound around a part of the pulley by a threaded ring 6-5.
For thick paper that cannot be fed using step 3, use insertion slot 1 at the right end of the main unit.
4, it can be directly fed into the paper feeding roller ruff.

Effects As described above, according to the present invention, it is possible to solve the problem of screen fading that occurs due to bottom-side transfer, and also to solve the problem of screen fading that occurs with the downsizing of copying machines. Heat transfer is prevented, and a remarkable effect can be obtained in reducing the size and cost of copying machines. Furthermore, by providing a louver or a valve in the ventilation duct, it is possible to prevent transfer defects caused by flutter of the thin transfer paper caused by airflow flowing into the transfer section.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the configuration of an embodiment of the present invention, FIGS. 2(a) and 2(b) are side sectional views showing the process unit in a closed state and a half-open state, respectively, and FIG. 3 is an implementation thereof. A perspective view showing the entire mechanism of the row seat insertion part, Figure 1 is an explanatory diagram explaining the effect of the louver on the duct, and Figure 5 is an explanatory diagram explaining the effect when a valve is provided in the duct. ...Copier main body, 2...-process unit 12-
1... Photoreceptor belt, 5... Original table glass, 6...
・Press plate, 6-4... Sheet inlet, 9... Charging/transfer charger, 1o... - Drive motor 10-1... Fan (air flow generating means), 11.12
... Duct, 11-1 ... Louver (opening that communicates with outside air), 12-
1...Transfer paper conveyance guide,

Claims (3)

[Claims] (1) In a copying device that transfers a toner image from a photoreceptor onto the lower surface of a transfer sheet and conveys the transfer sheet in that position to a fixing means for fixing, a transfer paper conveyance path is provided between the photoreceptor and the fixing means. An air flow path is provided that intersects with the air flow path, an air flow generation means is provided on the transfer surface side of the transfer paper, and a transfer paper conveyance guide that does not impede the air flow is provided above the portion of the transfer paper path that intersects with the air flow path. A copying device characterized in that: (2) The air flow path has an opening that communicates with outside air on the upstream side of the transfer paper path.
Copying device as described in Section. (3) The air flow path has a valve for blocking the air flow or restricting the flow rate on the upstream side of the transfer paper path and downstream of the opening communicating with the outside air, so that the transfer paper cannot cross the air flow path. 3. The copying apparatus according to claim 2, wherein the valve is closed in synchronization with the above.