JPH0244384A - Transfer material separator for image forming device - Google Patents

Abstract

PURPOSE:To apply sucking action to a transfer material according to the characteristic of the transfer material and to stably separate the transfer material without generating the disturbance of an image and a jamming by providing a means which varies generating air flow, and applying sucking action to a transfer material according to the transfer material. CONSTITUTION:A suction fan 5 is connected to a controller 7 which controls the rotational speed of the fan and the controller 7 is connected to a transfer material selecting switch 8 disposed on an appropriate place outside a device. The transfer material selecting switch 8 is changed over in advance by the operator of the image forming device so that the switch 8 corresponds with a transfer material; through the use of the controller 7, the rotational speed of the fan 5 is set at the value at which the speed meets the transfer material. Since sucking action meeting the condition of the transfer material is applied, stable separation is performed without having such trouble as defective separation resulting from deficient separating function, the occurrence of the jamming, and the disturbance of the image quality caused by excessive suction.

Description

Detailed Description of the Invention (1) Purpose of the Invention (Field of Industrial Application) The present invention relates to an image forming apparatus that utilizes an electrostatic transfer process, such as an electrostatic copying machine or a printer, and particularly to a transfer material separation device thereof. It is.

(Prior art and issues to be solved) In an image forming apparatus that electrostatically transfers a toner image formed on the surface of an image carrier onto a sheet-like transfer material such as paper, the toner image is applied to the transfer material during transfer. Since the transfer material tends to be attracted to the image carrier due to the electric charge, it is necessary to actively separate the transfer material from the image carrier by some means after the transfer.

As a separation means for this purpose, at the post-transfer position, a corona discharger is used to neutralize and eliminate the charge that the transfer material acquired during transfer, and the charge with the opposite polarity to that at the time of transfer is absorbed into the discharger. A configuration has been proposed in which a fan is provided to suck air in a direction in which the transfer material is separated from the image carrier to improve the separation function.

FIG. 4 schematically shows a typical example of such an apparatus, in which a transfer charger 12, A separation charger 13 is provided, and the toner image formed on the surface of the image carrier 10 is transferred to the transfer charger 1 as the photoreceptor rotates.
2, the transfer material P supplied from the conveyance path 11 reaches the transfer position at the same timing, and at this position, the transfer bias applied to the transfer charger 12 causes the transfer material P to be applied to the photoreceptor side. The toner image is transferred to the transfer material.

After the transfer, when the transfer material reaches the position of the separation charger 13, a bias with a polarity opposite to that during transfer is applied to the transfer material, and the charge that the transfer material has acquired during transfer is neutralized and removed, and the transfer material is exposed to light. The tendency of M to be absorbed by the transfer material decreases, and the transfer material separates from the photoreceptor due to its own elasticity and weight.

A suction fan 14 is connected to the separation charger 13,
Since air is sucked in the direction of the illustrated white arrow, the transfer material that is easily separated from the photoconductor is reliably separated from the photoconductor and is conveyed via the conveyance path 15 to a fixing site (not shown).

Although only a cleaning device is shown as 16 around the photoreceptor 10, it goes without saying that other members necessary for image formation, such as a secondary charger and a developing device, are also provided.

The above-mentioned configuration has been effective in separating the transfer material after transfer when there is not much change in the characteristics of the transfer material. It has become necessary to be able to use transfer materials with specific characteristics, and as mentioned above, separation y
The separation ability of the transfer material itself by k-electricity also varies significantly depending on the transfer material, so the above-mentioned separation means cannot be adapted to each individual transfer material, resulting in deterioration of image quality and occurrence of jams due to poor separation. Such inconveniences cannot be avoided.

To explain this, when two types of paper A and B, which have different characteristics as shown in Table 1 below, are used as transfer materials, the positions at which they separate from the photoreceptor will differ as shown in Figure 4. It's coming.

Table 1: Paper A, which is thick and rigid, is easy to separate, so it is quickly separated from the photoreceptor after transfer and transported to the fixing position on the transport path 15, as shown by the symbol A in the figure. However, paper B, which is thin and has low rigidity, does not separate sufficiently from the photoreceptor and follows this, and separates after progressing to a certain extent.

For this reason, the toner may come into contact with the cleaning device 16 located downstream of the normal transfer/separation charger and disturb the unfixed toner image, or even reach the cleaning device and cause a jam. Sometimes.

If the action of the suction fan 14 is strengthened to avoid such a situation, when the transfer material is separated, it will vibrate and cause image disturbance.

Furthermore, once an image is formed on the - side,
In the case of multiple or double-sided copying in which an image formation operation is performed on the core or back side, the original separation ability of the transfer material is lost due to the deformation of the transfer material caused by the initial operation. This causes separation failure. In particular, when using a fixing device that uses a heating roller, the above-mentioned inconvenience frequently occurs due to curling that occurs during copying of the first side.

The present invention has been made to deal with such a situation, and is an image forming apparatus configured to suck and separate the transfer material using a suction fan at the transfer material separation position. It is an object of the present invention to provide a separating device that provides a suction action to a transfer material and constantly provides an optimal suction action to perform a stable transfer material separation action without causing disturbance of one image or occurrence of jams. It is.

(2) Structure of the invention (technical means for solving the problem and its operation) In order to achieve the above objects, the present invention provides a method in which a transfer material is brought into contact with a transferable toner image formed on the surface of an image carrier, and at this position. An image forming apparatus comprising means for transferring the toner image onto a transfer material by applying a transfer bias using a transfer charger, and then generating an air current in a direction to separate the transfer material from the image carrier at a post-transfer position. The present invention is characterized in that a means is provided for changing the airflow generated in the transfer material according to the transfer material.

With this configuration, it is possible to perform stable and good separation of various transfer materials at all times.

(Description of Embodiments) FIG. 1 is a side view of essential parts showing an embodiment in which the present invention is applied to an image forming apparatus equipped with a 6-turn cylindrical photoreceptor similar to the known apparatus marked #. , a transfer charger 3 and a separation charger 4 are disposed close to the photoreceptor l rotating in the direction of arrow A, and the transferable toner image formed on the surface of the photoreceptor 1 is
As the photoreceptor rotates, the transfer material (not shown) is brought to the transfer site from the WI feeding path 2 in synchronization with the transfer charger 3, and along with this, a transfer material (not shown) is brought to the transfer site from the WI feeding path 2. A transfer bias is applied by a transfer charger, and the toner image on the surface of the photoreceptor is electrostatically transferred to the transfer material.

Then, the transfer material carrying this toner image is transferred to a separation charger 4.
When the transfer material reaches the position, a bias with a polarity opposite to that during transfer is applied by the charger, and the charge acquired by the transfer material during transfer is neutralized and eliminated, and the suction fan 5
Since an air current is formed in a direction that separates the transfer material from the photoreceptor l, the transfer material is separated from the photoreceptor due to the action of this airflow, and is sent to a fixing site (not shown) via the conveyance path 6. shall be carried out.

The above-mentioned operation and the fact that the members necessary for image formation are arranged around the photoreceptor 1 are not particularly different from those of the known image forming apparatus.

In the present invention, in such an apparatus, the suction fan 5 is connected to a fan rotation speed controller 7, and this is connected to a transfer material selection switch 8 disposed at a suitable location outside the apparatus.

The transfer material selection switch 8 is switched in advance by the operator of the image forming apparatus to correspond to the transfer material, and thereby controls the controller 7 to set the rotation speed of the fan 5 to a value suitable for the transfer material. shall be set. The table below shows the set rotational speed of the fan for the transfer materials A and B when copying the first side and when copying the second side.

Table 2 Unit: CPM (cycle per 5inite)
s) By setting the rotation speed of the fan according to the transfer material as described above, a suction action suitable for the condition of the transfer material is given to it, and separation failure due to insufficient gI function can be avoided.
A stable separation effect can be achieved without causing problems such as occurrence of jam or disturbance of image quality due to excessive suction.

FIG. 2 shows another configuration of the transfer material selection switch, and this figure shows only the portion corresponding to the fan control section in the apparatus of the embodiment.

The fan speed controller 7 is connected to a transfer material identification processing circuit 80, which has four contacts 81.
82, 83 and 84 are attachments.

Reference symbol C in the figure is a cassette for storing transfer materials, and a plurality of cassettes each storing different transfer materials are used. The provided cassette is installed in the image forming apparatus.

Therefore, the suction fan 5 can apply a suction action suitable for the transfer material stored in the cassette/container C at this time via the transfer material identification processing circuit 80 and the controller A-Rough.

Incidentally, instead of preparing a plurality of cassettes, the same effect can be obtained by making the contact C1 movable so that it contacts any of the contacts 81 to 84 at the seventh position depending on the stored transfer material. It is easy to understand that this is something that can be achieved.

FIG. 3 shows still another embodiment of the present invention, in which parts corresponding to those shown in FIG. The explanation for this will be omitted.

In this device, a shutter 9 is disposed at an appropriate position in a duct connecting the separated WF electric appliance 4 and the suction fan 5.

The shutter 9 includes a shutter member 9a and a pinion 9b for displacing the shutter member from a position where the duct is closed to a position where the duct is opened. The size of the opening of the duct is set to the output by the pinion rotation amount controller 70 activated by this, and the suction air volume is adapted to the characteristics of the transfer material to be used. This is an example showing the opening width of the shutter when copying the first side and copying the second side corresponding to A and H.

Table 3 Unit: 1111 With such a configuration as well, it is possible to impart a separating effect suitable to the characteristics of the transfer material, similarly to the apparatus of the above-described embodiment.

(3) As described in detail, according to the present invention, the toner image on the surface of the image carrier is electrostatically transferred to a transfer material in close contact with the toner image, and the toner image is electrostatically transferred at a position after transfer. In an image forming apparatus equipped with a means for generating airflow in the direction of separating the transfer material from the image carrier, the airflow is changed according to the characteristics of the transfer material, so that separation failure due to insufficient temperature can be avoided. It reliably prevents the occurrence of jams and image disturbances due to excessive air flow, and enables stable separation at all times, which greatly contributes to obtaining high-quality images.

[Brief explanation of the drawing]

FIG. 1 is a side view of essential parts of an image forming apparatus showing an embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams showing other embodiments of the present invention, and FIG. 4 is a known image forming apparatus. FIG. 1. Photoconductor, 2. Document transport path, 3. Transfer charger, 4. Separation charger, 5. Suction fan, 7.
Suction fan rotation speed controller, 8... Transfer material identification switch, 9... Shutter.

Claims (4)

[Claims] (1) A transfer material is brought into contact with the transferable toner image formed on the surface of the image carrier, a transfer bias is applied by a transfer charger at this position to transfer the toner image to the transfer material, and then the toner image is transferred to the transfer material at the position after transfer. , a transfer material separation device comprising a means for generating an airflow in a direction to separate the transfer material from an image carrier, the transfer material separation device comprising a means for changing the generated airflow depending on the transfer material. (2) The transfer material separation device according to claim 1, wherein the airflow is changed depending on the characteristics of the transfer material. (3) The transfer material separation device according to claim 1, wherein the airflow is changed depending on the order of image forming operations. (4) Claims 1 to 3, wherein the means for changing the airflow includes a shutter for opening and closing the suction duct.
The transfer material separation device according to any one of paragraphs.