JPS62145271A - Excessive sticking preventing method for offset preventing liquid - Google Patents

Abstract

PURPOSE:To prevent transfer paper whose size is switched from being contaminated with offset preventive liquid by arranging a member for offset preventive liquid removal in contact or closely to a fixing roller position except the passage area of the 1st transfer paper in the breadthwise direction of the transfer paper when the size of the transfer paper is switched. CONSTITUTION:When long-time continuous copying operation is performed by using the 1st transfer paper S1, mush offset preventive liquid sticks on parts on the both sides of a fixing roller 1 except the passing area of the transfer paper. When the 2nd transfer paper S2 is fed in this state, the area A of the transfer paper S2 is contaminated with the excessive offset preventive liquid. For the purpose, how many sheets of the 1st transfer paper are passed is counted properly and when the counted number reaches a set number and the size of the transfer paper is switched to S2, pieces 4 and 4 of wiping cloth contact the fixing roller 1, which is idles several times. Thus, excessive offset preventive liquid on the roller 1 is wiped off by the wiping cloth 4.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a method for preventing excessive adhesion of Offcera 1-prevention liquid.

(Prior Art) In a fixing device such as an electrophotographic copying machine, when a transfer paper is passed between a pair of fixing rollers, there is a risk that the image on the transfer paper may be transferred to the rollers. To solve this problem, anti-offset liquid such as silicone oil is applied to the roller on the side where the image passes.

In such a fixing device, when continuous copying is performed for a long time using, for example, A-column 4-size transfer paper, a large amount of paper is deposited on the surface of the fixing roller other than the A4-size paper passing area. of anti-offset liquid will adhere to the paper, and in this state, when a sheet of A3 size transfer paper, which is wider than A4 size, is passed through, the excess anti-offset liquid will cause the transferred paper to change its size. It gets contaminated.

(the purpose) An object of the present invention is to solve the above problems.

(Structure) In order to achieve the above object, the present invention provides a transfer paper fixing roller to which an anti-offset liquid is applied.

When passing a first transfer sheet of an arbitrary size, the number of sheets to be passed is counted, and when this count reaches a pre-stored set number or more and the first transfer sheet is On the other hand, when the size of the transfer paper is switched to a second transfer paper that is wider than this, at least in the width direction of the first transfer paper.

At the fixing roller part excluding the paper passing area of the first transfer paper,
It is characterized in that the anti-offset liquid removal member is brought into contact with or in close proximity to each other.

The present invention will be explained below based on one embodiment.

In FIG. 1, reference numeral 1 indicates a transfer paper fixing roller (hereinafter referred to as fixing roller) having an internal heat source, and 2 indicates a pressure roller that presses against the roller.

When the transfer paper S is passed between the rollers 1 and 2, the unfixed toner images 1 to 1 on the transfer paper are heated and fixed by the fixing roller 1.

When an unfixed toner image is heated and fixed, an anti-offset liquid supply roller 3 is applied to the surface of the roller 1 to prevent the toner image from being transferred to the surface of the fixing roller 1.
Anti-offset liquid such as silicone oil is applied using a supply means such as .

Figure 2 is a view of the fixing device in Figure 1 from the left side, and in this figure, S1 is assumed to be the first transfer paper of A row 4 size, and S2 is the wider A row 3 size transfer paper. It is assumed that this is the second transfer paper. In this embodiment, each transfer sheet is fed with reference to the central base line CL. In other words, it uses a central reference feeding method. Note that the present invention can also be applied to a one-sided reference method.

Here, while continuous copying is performed for a long time using the first transfer paper Sl, a large amount of anti-offset liquid adheres to the parts on both sides of the fixing roller 1 except for the paper passing area of the transfer paper. I come to do it.

In this state, when the second transfer paper S2 is passed through, a situation occurs in which the area indicated by the symbol A of the transfer paper S2 is contaminated with excessive anti-offset liquid.

In FIG. 2, with respect to the circumferential surfaces on both end sides of the fixing roller 1,
Offsera 1 - Wiping cloth 4, which is an example of a member for removing prevention liquid,
4 are arranged at a predetermined distance from each other. The wiping cloths 4, 4 are attached to both ends of the arm 6 via attachment plates 5, 5, respectively.

Here, the number of first transfer sheets S1 to be passed is appropriately counted, and this counted number is stored in a storage section of the control device (not shown).

When the count number reaches the set number of sheets stored in advance in the storage section and the transfer paper size is switched to 32, the wiping cloths 4, 4 come into contact with the fixing roller 1, and the fixing roller 1 is idling several times. Note that this is performed at least before the transfer paper S2 reaches the fixing roller 1.

During this time, excess off-cera 1 to prevention liquid on the roller 1 will be wiped off with the wiping cloth 4. In this case, even if it is wiped off, the offset prevention function can be achieved to a minimum.

The liquid film is left to remain.

Note that the wiping cloth 4 is used to wipe the roller surface to remove excess liquid, but in addition to this, such a removing member may be one that absorbs the anti-offset liquid. If the excess liquid can be removed by simply letting the

It does not necessarily have to be a contact method.

By removing excess anti-offset fluid.

Even if a wide second transfer sheet S2 is passed after the first transfer sheet S1, there is no risk that it will be contaminated by the anti-offset liquid, and the removal of the liquid to achieve this function is extremely easy. It can be done in a short time.

FIG. 3 shows a specific mechanism for driving the wiping cloth 4 into contact and separation. FIG. 4 shows an example of a control flow for implementing the present invention.

The control flow shown in FIG. 4 is designed to interrupt the main program as an interrupt subroutine when the size of transfer paper cannot be changed during normal copying.

When a series of copying operations is completed and a transfer paper size changeover switch (not shown) is turned on in this state, the process moves to the interrupt subroutine shown in FIG. 4, assuming that the size has been changed. In the next step, it is determined whether the number of copies that have been completed (stacked in the RAM) at this point in time is greater than or equal to a certain set number (for example, 200 copies).

If the number of sheets is greater than or equal to the set number, in the next step it is determined whether the switched transfer paper is larger than the previous one,
If it is large, the fixing roller 1 is idled several times and the solenoid 7 shown in FIG. 3 is energized.

When the solenoid 7 is energized, the arm rod 8 is rotated clockwise around the fulcrum 9 against the elasticity of the spring 10, so that the wiping cloth 4 comes into contact with the roller 1. This contact removes excess anti-offset liquid.

Note that if the previous number of copies is less than or equal to the set number, the process returns to the main program. If it is the same size as the previous one or smaller than the previous one, the program returns to the main program and the offset prevention liquid is not removed as described above.

(Effects) According to the present invention, when the transfer paper is changed to a larger size than the previous one, there is no risk of contaminating the changed transfer paper with the anti-offset liquid.

[Brief explanation of drawings]

FIG. 1 is a schematic side view of a fixing device embodying the present invention, and FIG.
The figure is a left side view of the fixing device shown in FIG. 1, FIG. 3 is a schematic side view of the fixing device with a wiping cloth contact/separation drive mechanism added, and FIG. 4 is an example of a control flow for carrying out the present invention. FIG. 1... Transfer paper fixing roller, 4... Wiping cloth as a member for removing offset prevention liquid.

Claims (1)

[Claims] The transfer paper fixing roller is coated with anti-offset liquid.
When passing a first transfer sheet of an arbitrary size, the number of sheets to be passed is counted, and when this count reaches a pre-stored set number or more and the first transfer sheet is On the other hand, when the size of the transfer paper is switched to a second transfer paper that is wider than this, at least the fixing area excluding the paper passing area of the first transfer paper in the width direction of the transfer paper A method for preventing excessive adhesion of anti-offset liquid by bringing an anti-offset liquid removal member into contact with or close to a roller portion.