JP3029127B2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine and a printer, and more particularly to an image forming apparatus having a fixing rotating body and a lubricant applying means.

[0002]

2. Description of the Related Art FIG. 1 shows an example of a fixing device used in an image forming apparatus.

An unfixed toner image T formed on a material to be transferred (plain paper or the like) P by an image forming method such as the well-known Carlson process is heated by a heater (not shown) inside in a final contact with each other. By passing through the nip portion of a roller pair composed of a fixing roller 31 and a pressure roller 32 having the pressure, the toner is pressed and heated to be fixed. Further, such a fixing device is generally provided with a release agent applying device 30 for applying a release agent in order to prevent the toner from being offset on the surface of the fixing roller 31. In the release agent applying device 30, a release agent 40 made of silicone oil is put in a release agent tank 39, is sucked up from the release agent tank 39 by the felt 33 held on the support plate 35, and is discharged to the felt 33. The contact and separation of the fused polymer synthetic resin film 34 and the fixing roller 31 are performed by a driving unit 36 and a support shaft 37. The amount of the release agent 40 sucked up by the felt 33 is adjusted by the polymer synthetic resin film 34, and the driving means 6 causes the fixing roller 31 to contact the polymer synthetic resin film 34 when the fixing roller 31 comes into contact with the fixing roller 31.
Is transferred to the fixing roller 31 when they come into contact with each other.

[0004]

Conventionally, when it is necessary to check that such a release agent applying member is impregnated with a functionally sufficient release agent, particularly when the apparatus is installed, the release agent is required to be inspected. If it is highly possible that the impregnation of the release agent is not sufficient, the felt 33 and the polymer synthetic resin film 34 must be exposed to check the impregnation state of the release agent.

[0005] For this reason, disassembling and assembling operations of the fixing device and the like are required, and it takes a long time to carry out the inspection. In addition, it is difficult to establish a clear standard because it is a subjective opinion of a service person to check whether the release agent application member is sufficiently impregnated with the release agent.

[0006]

Means for Solving the Problems To solve the above problems, the present invention provides an unfixed image forming means for forming an unfixed image on a recording material, and an unfixed image formed by the unfixed image forming means. A pair of rotating bodies for nipping and conveying the carried recording material and fixing the unfixed image on the recording material, and an application unit for applying a lubricating liquid in contact with the rotating body in contact with the unfixed image of the rotating body pair,
In the image forming apparatus, the recording material on which the unfixed image is not formed by the unfixed image forming means is caused to enter the rotating body pair, and then, when the recording material is sandwiched between the rotating body pair, the rotating body pair Is stopped, and then when the driving of the rotating body pair is started and stopped, the lubricating liquid at the position of the rotating body with which the applying means was in contact is transferred to the recording material to remove the recording material from the apparatus main body. In which a discharge mode is provided.

[0007]

Embodiments of the present invention will be described below.

FIG. 2 is a sectional view showing a main part of the image forming apparatus according to the embodiment of the present invention.

An image carrier, that is, a photosensitive drum 6, which is rotatably supported and rotates in the direction of the arrow, is uniformly charged by a primary charger 7, and a color-separated light image or a light image 8 corresponding thereto is formed. The exposure device includes an exposure unit that irradiates and forms an electrostatic latent image on the photosensitive drum 6, such as a laser beam exposure device, and a movable developing device 27 that visualizes the electrostatic latent image on the photosensitive drum 6. I do.

The movable developing device 27 includes four developing devices 2 for storing four color developers of magenta color developer, cyan color developer, yellow color developer and black color developer, respectively.
7M, 27C, 27Y, and 27Bk, and a guide that holds these four developing units and that can move in the horizontal direction.

The movable developing device 27 transports a desired developing device to a position facing the outer peripheral surface of the photosensitive drum 6, and develops an electrostatic latent image on the photosensitive drum.

The visible image on the photosensitive drum, that is, the toner image, is transferred to a transfer material P carried by a transfer / separation device 13 and conveyed in the direction of the arrow in FIG.

The transfer material P is fed by a resume roller 28 in synchronization with an image.

Reference numeral 23 denotes a suction corona charger for applying a charge having a polarity opposite to that of the toner to the rear surface of the transfer sheet. Reference numeral 24 denotes a conductive roller. Are driven by a drive system (not shown). The conductive roller 24 is grounded and serves as an opposite electrode of a suction corona charger. In addition, the charge is injected into the transfer material to cause the transfer sheet to suck the transfer material. At this time, the leading edge of the transfer material is overlapped with the cut of the transfer sheet so as not to enter the image area.
When continuous copying is designated by an operation panel (not shown),
If the length of the transfer material in the transport direction is equal to or less than half the length obtained by subtracting the width of the connecting portion from the peripheral length of the transfer drum, the second transfer material is fed after the first, and The second transfer material is attracted to the transfer sheet at the target position with the first transfer material. That is, two transfer materials are simultaneously adsorbed on the transfer sheet and transported. By doing so, a copying speed twice as high as when only one transfer sheet is adsorbed can be obtained.

A first color developer on the photosensitive drum,
For example, in order to transfer the magenta toner to the first transfer material, a charge having a polarity opposite to that of the toner is applied to the back surface of the transfer sheet using the corona charger 14 for transfer. Subsequently, the same latent image is formed again, the first color toner is developed on the photoconductor, and the first color toner is similarly transferred to the second transfer material.

The first transfer material is used for the second time by the conductive roller 24.
Is reached, the conductive roller 24 is released, and is separated from the transfer sheet by at least 2 mm from a position that does not disturb the transferred toner image.

The second color toner image formed on the photoreceptor in synchronization with the first transfer material to which the first color toner has been transferred is transferred using the transfer corona charger 14. Similarly, the second color toner image is transferred to the second transfer material. After the transfer step, a pair of ACs facing each other with the transfer sheet interposed therebetween is used to weaken the attraction force of the transfer material to the transfer sheet.
The charge is removed using a corona discharger.

In order to separate the first transfer material from the transfer sheet, the driven outer separation pressing roller 19 integrated with the separation claw 20 moves, and the curvature of the transfer sheet is locally reduced. First, a separation claw is inserted between the leading end of the first transfer material and the transfer sheet, and the transfer material is separated from the transfer sheet. When separating the second transfer material from the transfer sheet, the inner separation pressing roller 18 is pressed against the transfer sheet 31, and the outer separation pressing roller 19 is also guided.
The transfer sheet is pressed against the transfer sheet to locally reduce the curvature of the transfer sheet, the leading end of the transfer material is separated by curvature, and the separation is performed by inserting a separation claw 20 between the transfer material and the transfer sheet.

In order to prevent image flow due to peeling discharge that occurs when the transfer material and the transfer sheet are separated, it is preferable to perform an AC corona discharge using a corona discharger 17.

When the length of the transfer material in the transport direction is longer than that described above, the leading end of the transfer material is transferred to the same position as the leading end of the first transfer material, regardless of whether one copy or continuous copying is being performed. The same transfer and separation steps as in the case of the first transfer material are performed while being adsorbed on the sheet. At this time, the inner separation pressing roller is not driven.

After the transfer and separation steps are completed, the transfer material is sent to a fixing device 26 via a conveyor belt 25.

The fixing device 26 having the structure shown in FIG. 3 is used.

In this embodiment, there is provided a confirmation mode in which a service person automatically checks the application state of the silicone oil to the fixing roller.

Next, the confirmation mode will be described.

FIG. 3 is a flowchart showing the operation in the confirmation mode.

When a confirmation mode is instructed by operating the operation panel, first, A3-size copy paper, which is the maximum size transfer material of the apparatus, is fed.

At this time, no toner image is formed on the photosensitive drum 6, and no transfer discharge is performed on copy paper.

For this reason, the toner image is not formed on the copy sheet, and the copy sheet is conveyed to the fixing device as it is.

By not forming a toner image in this manner, it is possible to prevent the toner from being set to the fixing roller 31 when the silicone oil is not sufficiently applied to the fixing roller 31.

The release agent applying device 20 is driven in conjunction with the transport system, and before the leading end of the copy paper 11 reaches the position of the arc length L to the nip portion of the roller pair, the polymer synthetic resin film 34 is formed. And the fixing roller 31 are brought into contact with each other, and the copy paper 1
1 are separated from each other after passing through (not shown).

The release agent applying member composed of the felt 33 and the polymer synthetic resin film 34 applies an appropriate amount of the release agent to the surface of the fixing roller 31 when the fixing roller 31 is rotating at a predetermined process speed. It is adjusted so that it can be applied.

When the copy sheet P conveyed in the blank state is held between the nip of the roller pair including the fixing roller 31 and the pressure roller 32, the drive of the roller pair and the conveyance system are stopped at any time. Let it.

As described above, the driving of the roller pair and the transport system is stopped in a state where the release agent applying device 20 is in contact with the roller, so that the contact surface between the polymer synthetic resin film 34 and the fixing roller 31 becomes excessive. Of silicon oil is formed on the surface of the fixing roller 1 (FIG. 4). In this embodiment, a variable timer is used so that the drive time of the roller pair and the stop time of the transport system can be set arbitrarily.
Cause.

After a predetermined stop time (30 seconds in this example), the driving of the roller pair and the transport system starts automatically.

The oil dripping 16a generated on the surface of the fixing roller 31 moves to the nip portion of the roller pair as the fixing roller 31 rotates. At this time, the oil dripping 16a is transferred from the surface of the fixing roller 1 onto the surface of the copy paper P passing through the nip portion of the roller pair (FIG. 5), and the copy paper P
The oil dripping 16b is formed on the surface of the sheet P, and the copy sheet P is discharged from the fixing device.

The figure shows the state of the oil dripping 16b transferred on the surface of the copy paper 11. The portion indicated by the broken line of the copy sheet P is the position where the copy sheet 11 was located at the nip portion of the roller pair when the drive and transport system of the roller pair was stopped, and the deformation was caused by heating and pressing during the stop time. Has occurred. The oil dripping 16b is further behind the position indicated by the broken line and at a position of a distance L, that is, an arc length L in FIG.
Has been transferred to a position that is separated by a distance corresponding to. Also,
As described above, the release agent 4 supplied onto the surface of the fixing roller 31 from the polymer synthetic resin film 34 by the release agent coating device.
The application amount of 0 is adjusted to be an appropriate amount when the fixing roller 31 is rotating at a predetermined process speed. In this case, the transfer of the release agent 40 from the fixing roller 31 to the copy paper P is performed. Is extremely small and cannot be confirmed visually.

On the other hand, in this embodiment, by stopping the fixing roller and forming the oil dripping, the oil dripping 16b transferred on the surface of the copy sheet can be easily distinguished from other portions.

Therefore, the serviceman can check the oil application state by checking the oil dripping formed on the copy sheet in the confirmation mode.

Next, the service person judges whether the release agent applying member is sufficiently impregnated with the release agent 40 based on the state of the oil dripping 16b transferred to the copy sheet P obtained as described above. How to do this will be described.

The oil dripping 16 transferred to the copy paper 11
If b is transferred to the entire width of the copy paper P without interruption as shown in FIG. 6, this means that the release agent 4 is transferred from the polymer synthetic resin film 34 to the surface of the fixing roller 31.
0 indicates sufficient and uniform supply.

On the other hand, as shown in FIG. 7, when the oil dripping 16b transferred to the copy paper P is interrupted, the release agent 10 is supplied to the polymer synthetic resin film 34 corresponding to the interrupted portion. It was not done enough. From the above, if the oil dripping 16b is transferred without interruption over the entire width of the copy sheet P, it can be determined that the release agent applying member is uniformly impregnated with the release agent.

If the time for generating the oil dripping 16a is changed by stopping the driving and the conveying system of the roller pair, the density of the oil dripping 16b transferred to the copy paper P changes. Therefore, when the above-mentioned judgment is performed on the release agent application member having a relatively small amount of impregnation, which is impregnated with the release agent only to a degree that does not cause a problem in function, the concentration of the transferred oil dripping 16b is extremely low. It is preferable to set the time for stopping the drive of the roller pair and the transport system so that the transfer of the copy sheet P without interruption is barely confirmed. By confirming the transfer of the oil dripping 16b without interruption over the entire width of the copy paper P by the above-described method, it is extremely easy to impregnate the release agent coating member uniformly with the release agent, It can be determined that the impregnation amount is sufficient.

[0043]

As described above, according to the present invention, the application state of the release agent can be checked only by operating the confirmation mode by the service person, and the disassembly and assembly operations are not required, which is very simple.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of an example of a fixing device.

FIG. 2 is a schematic sectional view of the image forming apparatus according to the embodiment of the present invention.

FIG. 3 is a flowchart illustrating the operation of the embodiment of the present invention.

FIG. 4 is a cross-sectional view for explaining the operation of the present invention.

FIG. 5 is a sectional view for explaining the operation of the present invention.

FIG. 6 is a plan view of a recording material for explaining the present invention.

FIG. 7 is a plan view of a recording material for explaining the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 31 Fixing roller 32 Pressure roller 33 Felt 34 Polymer synthetic resin film 40 Release agent

Claims (2)

(57) [Claims] An unfixed image forming means for forming an unfixed image on a recording material, and a recording material carrying the unfixed image formed by the unfixed image forming means are nipped and conveyed to record the unfixed image on the recording material. An image forming apparatus comprising: a pair of rotating bodies fixed on the upper side; and an application unit for applying a lubricating liquid in contact with the rotating bodies in contact with the unfixed image of the pair of rotating bodies, wherein the unfixed image is formed by the unfixed image forming unit. The recording material not formed is caused to enter the rotating body pair, and then the driving of the rotating body pair is stopped when the recording material is sandwiched between the rotating body pair, and then the driving of the rotating body pair is started. An image forming apparatus having a mode in which the lubricating liquid at the position of the rotating body contacted by the applying unit when the application unit is in contact with the recording material is discharged to the outside of the apparatus main body. 2. The image forming apparatus according to claim 1, wherein the application unit is capable of coming into contact with and separating from the rotating body, and applies the lubricating liquid at least in contact with the rotating body at the time of fixing.