JPH03164758A - Paper separater for electrophotographic device - Google Patents

Abstract

PURPOSE:To surely separate an elastic sheet by elastically deforming an elastic roll by means of a rotatable pressing member, and providing the leading end of a separating member without contacting the elastic roll in the vicinity of the pressuring member part and at a position encroaching on the surface of the elastic roll prior to deformation. CONSTITUTION:This device is provided with the elastic roll for carrying a sheet 2 composed of an elastic body, the sheet separating member 5, and the pressing member 4 which is rotatively brought into contact with the elastic roll 2 and partly depresses the surface of the elastic roll 2. The pressing member 4 is integrally engaged with the separating member 5, and provided so as to rotate, it. Further, the leading end of the separating member 5 encroaches on the side of the elastic roll 2 compared with the position of an outer periphery before the elastic roll 2 is deformed, and is maintained without contacting the elastic roll 2. The separating member 5 is disposed in the vicinity of the pressure point of the pressure member 4. Thus, a sheet is surely separated from an elastic roll, a defect in fixing is prevented, and the life of the elastic roll is prolonged.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a device for separating paper from an elastic roll for transporting paper in an electrophotographic apparatus.

[Conventional technology]

Conventionally, in the heat fixing section of an electrophotographic apparatus, fixing is performed while conveying the paper using a relatively hard heat roll and an elastic roll provided opposite the heat roll.1. Due to electrical charges on the paper, the paper wraps around the elastic roll, resulting in poor paper conveyance. Therefore, an attempt has been made to provide a separation member for paper separation near the nip point between the heat roll and the elastic roll to separate the paper stuck to the elastic roll from the elastic roll.

[Problem to be solved by the invention]

This conventional technique has the following drawbacks.

That is, the thickness of the paper used in this type of device is 0.
It is not uncommon for the separation member to be less than 1 inch. Therefore, it is necessary to maintain and fix the separation member and the elastic roll at a distance commensurate with the thickness of the paper.
Setting it close to mm requires a lot of man hours. In addition, slight variations in related dimensions such as eccentricity of elastic roll 1 may cause the separation member to hit the surface of the elastic roll and cause damage, resulting in poor fixing, or conversely, separation member 1 may become too far away from the elastic roll. , the inherent problem is that the paper separation function is lost.

SUMMARY OF THE INVENTION An object of the present invention is to provide a paper separation device for an electrophotographic apparatus that can reliably separate paper from one elastic roll, prevent poor fixing, and extend the life of the elastic roll.

[Means to solve the problem]

In order to achieve the above object, one aspect of the present invention is a paper separation device for an electrophotographic apparatus.

1. A paper separating device for an electrophotographic apparatus including an elastic roll made of an elastic body for paper conveyance and a paper separating member.

The pressing member includes a pressing member that rotates in contact with the elastic roll and partially indents the surface of the elastic roll, the pressing member is integrally engaged with the separating member and is rotatably provided, and the separating member The tip of the elastic roll bites into the elastic roll side from the outer surface position of the elastic roll before deformation, and is held at a position not in contact with the elastic roll, and the separating member is located near the pressing point of the pressing member. It is characterized by being installed.

In 2.1.

While the elastic roll is rotating, the pressure member is pressed against the elastic roll with a predetermined load, and when the elastic roll is stopped rotating, it is removed from the elastic roll.

3. In claim 1 or 2, the elastic roll is a pressure roll provided opposite to a heat roll, and the separation member is provided downstream of the nip point.

[Effect]

In the present invention, the rotatable pressure member is integrally engaged with the separating member, the tip of the female member bites into the elastic roll side from the outer surface position of the elastic roll before deformation, and one elastic roll has the following features: Placed in a non-contact position. Therefore, it is possible to reliably separate the paper from the elastic roll, prevent poor fixing, and extend the life of the elastic roll.

〔Example〕

An embodiment of the present invention will be described based on FIGS. 1 and 2.

FIG. 1 is a sectional view showing an embodiment of the paper separating device of the present invention, and FIG. 2 is a partial explanatory view of FIG. 1.

A sheet of paper 1 holding an unfixed toner image 11 is held between a heat roll 3 and an elastic roll 2, and is conveyed as the heat roll 3 rotates in the direction of the arrow, and is moved several times along the axial direction of the elastic roll 2. Elastic roll 2 with separating member 5 provided at a location
It is peeled off from the paper, passes through the paper guide 9, and is delivered to the stacker 6.
stored inside. Paper 1 indicates the case of a cut sheet.
In order to prevent toner offset, the heat roll 3 is provided with a Teflon layer on its surface and coated with oil by an oil coating mechanism (not shown). The elastic roll 2 rotatably supported opposite the heat roll 3 is made of fluororubber,
Alternatively, it is made of silicone rubber, is pressed against the heat roll 3 with a load of about 100 kg, and rotates in the direction of arrow B as the heat roll 3 rotates in the direction of the arrow. Also,
The elastic roll 2 is structured to separate from the heat roll 3 when not printing. During the dry period, the paper 1 may wind around the elastic roll 2 after passing through the nip point between the heat roll 3 and the elastic roll 2 due to charging or other reasons.

A pressure member 4 is provided downstream of the nip point, and is rotatably supported by the paper guide 9 and is pressed against the elastic roll 2 by a solenoid 7 with a predetermined load via a spring 25.
The pressure member 4 rotates in the direction of arrow C as the elastic roll 2 rotates in the direction of arrow B. The pressure member 4 is made of heat-resistant and wear-resistant resin, and the pressure member 4 and the elastic roll 2
At the contact point 12 with the elastic roll 2, as shown, the elastic roll 2
It is elastically deformed and concave. A separating member 5 fixed to the tip of the paper guide 9 is arranged near this contact point 12, and the tip of the separating member 5 digs into the surface of the elastic roll 2 by Δ1 more than the surface before deformation. Several separation members 5 are newly provided in the axial direction of the elastic roll 2, and the paper 1 is guided to the surface of the elastic roll 2 where the separation member 5 is not provided, and the paper 1 is reliably mounted on the separation member 5 and separated from the elastic roll 2. Ru. Of course, only the tip end of the separation member 5 is designed to be narrower than the width of the pressure member 4.

The amount of deformation Δ of the elastic roll 2 is the amount that is possible after one elasticity. Further, the positional dimension Δ2 between the pressure member 4 and the separation member 5 is determined by the manufacturing dimension, and the amount of deformation Δ3 of the elastic roll 2 at the tip of the separation member 5 is determined by the elasticity of the elastic roll 2 and the applied force. It is determined by the pressure applied by the pressure member 4.

In this example, by selecting numerical values that fully consider these parameters, each of Δ1 and Δ2−Δ3 can be kept at a sufficient value of about 0.2 to 0.3 mm or more, and the elastic roll 2 The paper 1 can be reliably separated from the elastic roll 2 without being damaged by the separation member 5. Furthermore, even if the elastic roll 2 is eccentric due to manufacturing reasons, Δ2 is physically constant after the pressure member 41 and separation member 5 are manufactured, and the value of Δ3 is determined by the elastic roll 2 while the pressure member 4 is rolling. virtually because it follows the surface of.

Since it is constant enough to cause no problems, there is no need to separate the sheets due to vibration of the outer surface due to eccentricity of the elastic roll 2. A side plate (not shown) that supports the elastic roll 2 supports the paper guide 9 and is designed to maintain the accuracy of the positional relationship between the pressure member 4 and the elastic roll 2.

The paper guide 9 is rotatably supported around a fulcrum 10, and when the elastic roll 2 stops rotating, the solenoid 7 is turned off and the restoring spring 8 rotates it counterclockwise around the fulcrum 10. , the pressure member 41 separation member 5 is removed from the elastic roll 2, and the elastic roll 2 is removed while the apparatus is stopped.
The pressure member 4 is designed to prevent partial loss of elasticity.

Note that the present invention may be modified as follows.

(1) In the embodiment, during the rotation of the elastic roll 2, the pressure member 4
Although the paper 1 is pressed against the elastic roll 2 with a predetermined load, the pressing load may be controlled depending on the positional relationship between the paper 1 and the elastic roll 2.

(2) Although the solenoid 7 was used to remove the pressure member 4 from the elastic roll 2, a knob point release operation may be used to separate the elastic roll 2 from the heat roll 3.

(3) The pressure member 4 and the separation member 5 may have a structure in which they are held with the rotation axis of the elastic roll 2 as a reference.

(4) Continuous paper may be used instead of cut sheets.

〔Effect of the invention〕

According to the present invention, a rotatable pressure member is pressed against the elastic roll under a predetermined load, the elastic roll is elastically deformed, and a position near the pressure member is dug into the elastic roll than the surface of the elastic roll before deformation. Since the tip of the separating member is provided in a non-contact manner with the elastic roll, the paper can be reliably separated from one elastic roll, and the paper does not get wrapped around the elastic roll. This prevents fixing defects and extends the life of one elastic roll.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the paper separating device of the present invention, and FIG. 2 is a partial explanatory view of FIG. 5 is a separation member.

Claims (1)

[Scope of Claims] 1. A paper separating device for an electrophotographic apparatus including an elastic roll made of an elastic body for transporting paper and a paper separating member, in which the surface of the elastic roll is partially touched by rotationally contacting the elastic roll. The pressing member is integrally engaged with the separating member and is rotatably provided, and the tip of the separating member is located at a position on the outer surface of the elastic roll before deformation. The sheet of paper for an electrophotographic apparatus is characterized in that the paper sheet bites into the elastic roll side and is held in a position not in contact with the elastic roll, and the separation member is installed near a pressure point of the pressure member. Separation device. 2. In claim 1, while the elastic roll is rotating, the pressing member is pressed against the elastic roll with a predetermined load, and while the elastic roll is not rotating, the sheet of the electrophotographic apparatus is separated from the elastic roll. Separation device. 3. A paper separation device for an electrophotographic apparatus according to claim 1 or 2, wherein the elastic roll is a pressure roll provided opposite to a heat roll, and the separation member is provided downstream of a nip point.