JPS58196559A - Image forming apparatus - Google Patents

Abstract

PURPOSE:To prevent scattering of toner, and to make it sure to separate a sheet difficultly separable from an image bearing drum, by controlling speed of the air sent from an air fan in accordance with a kind of sheet. CONSTITUTION:A transfer sheet 1 comes into contact with the drum 6, and a visible toner image is transferred with a transfer corona discharger T from the drum 6 to the sheet 1, and the sheet 1 is separated from the drum 6 by the electrostatic separation method using a corona discharger 7 and flow of air 9 fed from a fan 8 through a duct 8a toward the drum 6 surface. When a cassette contg. thick sheets of paper ordinarily used is fitted to the main body, the flow rate changeover switch 15 of a detector detects it and the flow speed of the fan 8 is controlled to 0-1m/sec with a controller 16, and when a cassette 2 contg. hardly separable light weight sheets exclusively used for intermediate originals is fitted to the main body, the flow speed is controlled to 0.93-1.7m/ sec to stabilize separation of limp paper sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION Misfire E94 relates to the use of electrophotographic copying machines, recording machines, and the like.

The following is an explanation using a copying machine as an example.

The map transfer machine uses an electrostatic separation method to remove sheets such as transfer paper and photo paper (hereinafter referred to as transfer paper) from an image carrier such as a drum (hereinafter referred to as drum). There are things that are transported and fixed by

Conventionally, when this electrostatic separation type tube is used, a charger is used as the first SL+ stage to reduce the electrostatic attraction force between the paper and the drum, a separation claw is used as the second separation means, and a drum such as air blower is used as the second separation means. The two methods of removing the transfer paper and removing it are often used in combination. This is because if only the first separation means is used, it is difficult to separate the transfer paper reliably due to differences in the type of transfer paper used, strong paper or weak paper, degree of iron layer, etc. be. If the transfer paper cannot be separated by the first separation means C and moves while being wrapped around the drum J, it will plunge into the cleaner section and cause a contraction/opening jam. For this purpose, for example, an air blowing section is installed near the drum transfer unit, and the tip of the transfer paper is peeled off by air force, or the separating claw is
A means ft for physically peeling off by contacting the drum is provided.

However, when these means are used, the following problems arise.

When f-separation claws are used, since the transfer paper is forced to come into contact with the drum because it is necessary to peel it off, if a large number of copies are made, the drum will be scratched, which will affect the image quality. When separating air is used, if the wind speed is set to ensure that it can separate all the transfer paper from the drum, the untransferred toner on the drum and the unfixed toner on the rolled paper will be blown away, causing scattering. Therefore, in order to reduce the degree of this scattering, it is ideal to reduce the air blowing pressure as much as possible, but if it cannot be separated with a saw, the problem of transfer paper that is difficult to separate, such as the second original. To provide an image forming apparatus which eliminates the above problems, prevents toner from scattering, and can reliably separate even a sheet that is difficult to separate from an image carrier.

That is, the present invention includes an a%gl carrier, an image forming means for forming an image on the image carrier, and an electrostatic separating means for separating the image-transferred sheet on the carrier from the surface of the image carrier. , an air blowing means that cooperates with the separation of the sheet from the image carrier by the electrostatic separation means, and a means for adjusting the wind speed fil- from the air blowing means depending on the type of sheet. This is a simplified diagram.

As shown in FIG. 2, the transfer k l Vi s is sent out from the cassette 2 by the rotation of the paper feed loaf 3 . 1 soshi-(,
It comes into contact with the register roller 4 and waits. At the same time, the original oFi placed on the movable original table S (in the direction of arrow a)
, the lamp L is irradiated. Then, the reflected light image is irradiated by the set focusing imaging element array M onto the second surface of the drum 6, which has been given a charge f in advance by the corona discharger 18. The electrostatic latent image 4 formed on the drum 6 according to this reflected light image is oJ
It becomes a visual image. The transfer paper 1, which has been waiting in contact with the register roller 4, is sent out by the register roller 4 when the same visible image A11t appears. First, the sent-out transfer paper] comes into contact with the drum 6, and after the transfer corona discharger T transfers the visual image of the drum 6F:, 0IjT, the corona discharger 7 of the electrostatic separation means (the first (10 stages of separation) and air blowing means (the above-mentioned second separation means);
7 l) Prower 8 and duct 8 connected to the prower 8
It is separated from the drum 6 by the wind 9Vc from a to the surface of the drum 6. Transfer paper 1 separated by drum 6
After that, the transfer paper passes through the foot guide 11 and the two-hand paper discharge roller 13 to the conveyance section IO.
Torezu 14... is ejected.

On the other hand, in this embodiment, dedicated cassettes are provided depending on the type of sheet. Therefore, the type of sort to be separated is determined based on the cassette loaded into the 1ktIt main body.

That is, in this embodiment, the detection device 15 is provided on the device main body side,
Lightweight paper 2nd original drawing cassette 2@feeding direction tip@&2
Detection button 17tflin/ko on a.

Control of wind wrinkles will be explained below.

FIG. 2 is a circuit diagram for controlling the it% wind shift.

First, let's start with the commonly used cardboard (for example,
When a cassette (r shown in the figure) containing 80g paper is loaded into the main body, the detection fin 18 of the blower-fan air volume selector switch 15 as a detector is connected to the rNOJ side terminal, and the current flows through the blower-8 Electricity is applied between the terminals (A-C). Based on this detection, the control unit 16 controls the wind speed of the blower 8 to θ to 1 m/s (longitudinal average).

Lightweight paper that stores sheets that are difficult to separate - 2nd JI
When the figure-only cassette 2 is loaded into the main body, the fin 18 of the changeover switch 15 is switched to rNC by button /17.
The current is connected to the terminal on the J side, and the current is connected to the terminal on the pro 9-8 (A
-B) is energized. Therefore, based on this detection, the control section 16 adjusts the storm chain of the prower 8 to α93~1.7''/
1 (average in the operator's direction) to stably separate even weak paper.

As described above, in this embodiment, when separating paper that is difficult to separate, the amount of air blowing is increased to stabilize the paper 111 times.

In this embodiment, the type of sheet is determined based on the cassette.

The present invention is not limited to this example; for example, when special paper that is difficult to separate is used, the operator can press a button (not shown) to give a signal to the control unit to increase the air volume. It's okay.

FIG. 3 shows the timing of the relationship between the changeover switch 15 and the wind noise of the blower 8.

As shown in FIG. 3, a predetermined time after the changeover switch 15 is turned on, the control unit 16 outputs a fan drive signal along with a signal to increase the air volume, and in response, the fan increases the air volume for a predetermined time. It rotates and then stops. 1+,
In the case of only the normal fan drive signal Kfl, the fan rotates at the normal air volume and then stops.

As described above, the present invention provides an image forming apparatus that adjusts the air blowing lance for separation according to the type of sheet and stabilizes the separation.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a copying machine to which an embodiment of the present invention is applied;
Fig. 2 is a circuit diagram showing the controll of the dragon, and Fig. 3 is a timing diagram. In Figure 2, 1 - Transfer paper 2 - Dedicated cassette 16 - Drum 8 - Blower - 15 - Detection device 16 - Control section 18 - Fin applicant Canon Co., Ltd.

Claims (1)

[Claims] (1) With an image carrier. #A An image forming sub-actor that forms an image on the image carrier, and an electrostatic separation means that separates the image-transferred sheet on the image carrier from the surface of the image carrier. and an air-blown wave that cooperates with the separation of the /-t from the image carrier by the electrostatic separation means. An image forming apparatus* that is characterized by having means for adjusting the wind speed from the air blowing means according to the type of sheet.