JPS5937563A - Picture forming device - Google Patents

Abstract

PURPOSE:To prevent a couple of fixation rolls from deforming through simple, inexpensive constitution and to perform stable fixation, by allowing a heat roll and a pressing roll to contact and leave each other interlocking with the reciprocation of a reciprocating means for exposing an original. CONSTITUTION:A fixation device 17 consists of the heat roll 17a incorporating a heater and the elastic pressing roll 17b; the pressing roll 17b is supported pivotally on a lever 19 rotating around a supporting shaft 18 as a fulcrum and energized by a spring 10 to be pressed against the heat roll 17a, but a roll 21 fixed to a platen 2 abouts on the front end of the lever 19 when copying operation is not performed, so the rolls 17a and 17b are separated from each other. When the platen 2 moves during copying operation, the roll 21 leaves the lever 19 to press the roll 17b against the roll 17a, performing the fixation. Even if transfer paper is wound around the roll 17, it is removed easily. Therefore, the stable fixation is performed.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention provides an image carrier that carries a developed developer image after exposure, by passing it between a pair of fixing rollers.
The present invention relates to an image forming apparatus in which an L developer image is fixed.

[Technical backbone of the invention and its problems, 1] For example, in a fixing device of an electronic copying machine, a developer image on an image carrier such as paper is fixed using a fixing roller pair consisting of a heating roller and a pressure roller. It is known that it sticks.

This type of fixing device has a heating roller whose periphery is coated with a release material and is equipped with a heating device inside, and a pressure roller with rubber-like elasticity that is brought into contact with the roller, and the image carrier is passed between them. The developer image on the image carrier is fixed by heat and pressure.

On the other hand, in this type of fixing device, when the copying speed is slow, good fixing results can be obtained even if the heat and pressure applied between the pair of rollers is relatively low; however, when the copying speed is changed at a high speed of 20 sheets per minute or more, Therefore, large values of heat and pressure are required to be applied between the rollers. If the heat and pressure applied between the rollers is low, there is no problem even if the rollers are kept in constant pressure contact, but if the heat and pressure are high, the rotation of the rollers may stop, such as when the copying machine is stopped. If the pressure contact is left as it is, there are problems such as deformation of the pressure roller with J-wristing property [7] and uneven fixing.

Therefore, a method has been proposed in which the pair of fixing rollers is brought into pressure contact only during copying operations, and is separated from each other during non-copying operations. However, in the conventional approach and separation FA side of the pair of fixing rollers, a force l is driven to a dedicated solenoid to displace the support arm to which the pressure roller is attached against the biasing force of the roller press ring. - The structure is complicated and the manufacturing cost and running cost are low.

[Purpose of the invention]

The present invention has been made based on the following two circumstances, and aims to provide a relatively simple and inexpensive structure that can reliably prevent deformation of a pair of fixing rollers and maintain stability over a long period of time. It is an object of the present invention to provide an image forming apparatus in which fixing can be performed in a fixed manner, and also in the case where an image carrier is wrapped around a fixing roller, it can be easily removed.

[Summary of the Invention] In order to achieve the above object, the present invention is constructed so that the fixing rollers are moved toward and away from each other in conjunction with the reciprocating movement of the reciprocating means for exposing a 1-mm original, and a dedicated No need for a driving source 1. It is something that

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described with reference to No. 11"4 and FIG. is equipped with a document table 2 and a main body 1.
It is moved back and forth by a drive mechanism (not shown) provided inside. The moving distance of the document table 2 changes depending on the document size.

Further, in the center of the main body 1, there is provided a drum-mounted photoreceptor 3 that rotates in a predetermined direction in synchronization with the document table 2, and around the photoreceptor 3 there is a charging device 4 and an exposure device 4. An imaging section 5a of the device 5, a developing device 6. A transfer device 7, a peeling device 8, a static eliminator 9, and a leaning device 10 are sequentially arranged along the rotational direction of the photoreceptor 3.

Further, inside the main body 1, a transfer paper 2 as an image carrier supplied from a paper feeder 11 is placed between a photoreceptor 3 and a transfer device 7.
Peeling 141 by the paper feed path 1.9 and the peeling device 8
Transfer paper 12 onto which the developer image has been transferred is transferred to paper ejection roller pair 1.
A paper discharge path 16 is formed which leads to the tray 15 via 4.14.

A fixing device 17 for fixing the image (i') on the transfer paper 12 is provided in the middle of the paper discharge path 160) U'f1.

This fixing device 17 includes a heating roller 1711 coated with a releasing material and equipped with a heater inside, and a rubber-like roller 1711.
``It consists of a pressure roller 17b with an elastic body.

12, when the copying operation is started, the photoreceptor 3 rotates and the document table 2 moves forward. At this time, this movement-
Each device disposed around the photoreceptor 3 operates in synchronization with each other to carry out charging, exposure, and development processes, and a developer image corresponding to the original is formed on the photoreceptor 3. .

On the other hand, in synchronization with the operation of forming the developer image on the photoconductor 3, a transfer paper 12 is fed from the paper feeder 11, and the transfer paper 12 is superimposed on the developer image, and at the same time, due to the action of the transfer device 7, F. The developer image is transferred to transfer paper 12.

Then, the transfer paper 12 containing the developer image transfer material is peeled off from the light body 9 by a peeling device 8 and sent to a fixing device I2).
The developer image is fixed by heat and pressure by passing between the 111 heat roller 17B and the pressure roller 17b which are in contact with each other.

After the fixing is completed, the transfer paper J2 is discharged by the roller pair 14.
14) +/i 15.

On the other hand, the upper roller 77h is the heating roller 17B.
Against 1. During non-copying operations, the heating port is moved away from the heating port as shown by the two-dot chain line in FIG.

That is, as shown in FIG. 2, the pressure roller 17b is pivotally supported by the middle part of the lever 19 which can rotate about the support shaft 18. This lever 19 has a spring 20
The L mud pressure roller 17b is always urged to rotate clockwise in the figure by the heating roller 17a.
It is designed to come into pressure contact with the

Further, the tip of the lever 19 protrudes into the movement path of a roller 21 attached to the document table L 2, and as the document table 2 moves back and forth, the lever 19 is pushed against the biasing force of the spring 20. It has a structure that allows for rotational displacement.

When the document table 2 starts to move from the home position due to the copying operation, the roller 21 that was pressing the lever 19 due to the biasing force of the spring 20 comes off the lever 19, and the pressure roller 17b is heating roller 1
711 is in pressure contact.

When the copying operation is completed, that is, when the document table 2 returns to the home position, the heating roller 17a and the pressure roller 17b are separated from each other.

In addition, in the unlikely event that the transfer paper 12 is wrapped around the pair of fixing rollers 17a and 17b or there is a jam, the document table 2 returns to the home position and the pair of fixing rollers 17a and 17b is fixed.
, xyb are spaced apart, so that their removal work can be easily performed.

In the above-mentioned embodiment, following the movement of the document table 2, the fusing roller 17b is moved from the heat roller 1 to the heat roller 1.
7b (The present invention is not limited to this, but may be as shown in FIG. 3. In other words,
In the case of a type in which the document table 2 is fixed and the optical block 22 of the exposure device 5 moves back and forth, the roller 21 is housed in the optical blower () 22, and its movement is utilized. It may be arranged to be separated from the Moreover, although the pressure roller J7b is moved, the heating roller 17a may be moved.

In short, any configuration may be used as long as the fixing rollers can be moved toward and away from each other in conjunction with the reciprocating means for exposing the document.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the gist of the invention.

In the description of the L distribution example (Fig. 3), the same parts as in the above-mentioned example are given the same reference numerals and the description will be omitted.

〔Effect of the invention〕

As described above, the present invention is configured to move the fixing rollers toward and away from each other in conjunction with the reciprocating movement of the reciprocating means for exposing the original. Therefore, although the configuration is relatively simple and inexpensive, it is possible to reliably control the approach and separation of the pair of fixing rollers, prevent deformation of the fixing roller, and perform stable fixing over a long period of time. Further, even when the image carrier jams (the image carrier is wrapped around the fixing roller), the pair of fixing rollers can be separated by moving the reciprocating means to a predetermined position, and the image carrier can be easily removed.

[Brief explanation of the drawing]

Figure 8g1 and Figure 2 show one embodiment of the present invention, Figure 1 is a schematic longitudinal sectional front view, Figure 2 is a partially cutaway schematic front view, and Figure 3 is another embodiment of the present invention. Partial cutout showing an example 1. FIG. 2... Original platen, 12... Image carrier (transfer paper) 1
2...Fixing device, 17a...Heating roller 17
b...Pressure, WO-t, 22...Optical block applicant's agent Patent attorney Takehiko Suzue Figure 1 Figure 2 Figure 3-1

Claims (3)

[Claims] (1) An image comprising a reciprocating means for exposing a document and a pair of fixing rollers for fixing the developer image by passing the developed developer image through an image carrier after exposure. 1. An image forming apparatus characterized in that the fixing rollers are moved toward and away from each other in conjunction with the reciprocating movement of a reciprocating means. (2) Immediately after the reciprocating means makes a forward movement for exposure, the fixing row → pair comes into pressure contact with each other, and after the reciprocating means makes a return movement, they are separated by a large distance. An image forming apparatus according to claim 1. (3) The image forming apparatus according to claim 1 or 2, wherein the pair of fixing rollers includes a heating roller and a pressure roller.