JPH0615064U - Image forming apparatus having fixing device - Google Patents

Abstract

(57) [Summary] (Correction) [Purpose] The pressure of the heat fixing roller and the pressure contact roller of the fixing device can be adjusted according to the type of recording paper, and the fixing device can be securely attached to and detached from the main body. An apparatus is provided. A heat fixing roller having a built-in heat source, a pressure contact roller for pressure contact of the recording paper P, which is opposed to the heat fixing roller 17, and the pressure contact roller are pivotally supported and pivotally attached to a part of a fixing device frame. The movable frames 162 and 163, the first fixing spring member provided in a part of the movable frame, the lever member pivotally attached to the fixing device frame body, and the movable frame are movable in order to press the heat fixing roller against the pressure roller. In order to make one end of the lever member abut against a part of the movable frame, and to press the heat contact roller 17 to the heat fixing roller 17 via the movable frame, the second spring member provided in the lever member and the other of the lever member An operating member that is operated at one end and is urged to one side, a setting member that sets a certain position against the urging force of the operating member, and an other end of the lever member that operates in cooperation with the setting member. A fixed member characterized by being provided with an operating member to be operated. An image forming apparatus having a fixing device 15.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a fixing device for thermally fixing a toner image on a recording paper used in a printer, a copying machine or the like which is an image forming apparatus.

[0002]

[Prior art]

 In the image forming apparatus, a toner image is formed on a photoconductor using an electrophotographic process, the toner image is transferred onto a recording paper using a transfer pole, and the recording paper is separated from the photoconductor. The toner image on the recording paper is thermally fixed by the heat fixing roller to fix the toner image on the recording paper. A fixing device is used that efficiently fixes the recording paper by pressing the recording paper against the heat fixing roller. A rotating pressure contact roller is used as the pressure contact means, and the recording paper is pressure-bonded between the pressure contact roller and the heat fixing roller for heat fixing. In the case of using such a pressure bonding method, if the recording paper is narrowed between the heat fixing roller and the pressure contact roller and stopped due to some trouble, the recording paper cannot be taken out. A device for manually releasing the pressure contact roller is provided so that the recording paper can be taken out even when such a failure occurs. Then, as described above, the toner image transferred onto the recording paper is heat-fixed by the heat fixing roller and the pressure contact roller, but the pressure contact roller uses the normally used 45 kg paper or 70 kg paper. At this time, the pressure contact roller is pressed against the heat fixing roller using a spring or the like so as to obtain the optimum pressure contact force. However, when a toner image is fixed on a recording paper by using an image forming printer, a variety of moving recording papers are used unlike the copying work of a document. Particularly, characters and images are formed on the surface of a thick envelope and heat-fixed. In such a case, an operating lever for changing the pressure force between the heat fixing roller and the pressure contact roller is provided on the fixing device side. Further, an operation lever is provided on the main body side of the apparatus for operating the operation lever on the fixing apparatus side.

[0003]

[Problems to be solved by the device]

 When the fixing device is removed from the main body of the image forming apparatus as described above, the operating lever of the fixing device moves outward due to the elastic force of the spring for pressing the heat fixing roller against the pressure roller. I will end up. If the fixing device is again attached to the apparatus main body in this state, there is a disadvantage that the tip of the operating lever on the fixing device side and the operation lever on the apparatus main body side hit each other before the attachment so that the fixing device cannot be attached.

An object of the present invention is to eliminate such drawbacks and to mount the fixing device having the above-mentioned operating lever on the main body of the device in a safe and reliable manner.

[0005]

[Means for Solving the Problems]

 In order to achieve the above object, the present invention provides a fixing device for fixing a toner image formed on a recording paper by heat fixing, and a heat fixing roller having a built-in heat source, and a recording paper pressure contacting member provided opposite the heat fixing roller. A pressure contact roller, a movable frame pivotally supporting the pressure contact roller, and pivotally attached to a part of the fixing device frame, and provided in a part of the movable frame to press the heat contact roller against the heat contact roller. A first spring member, a lever member pivotally attached to the fixing device frame, one end of the lever member for moving the movable frame, and one end of the lever member held against a part of the movable frame, and the movable frame. A second spring member provided on the lever member for pressing the pressure roller against the heat fixing roller, an operating member that operates the other end of the lever member and is urged to one side, and an operating member Set a certain position against the power. An image forming apparatus having an image forming apparatus having a fixing device, which is provided with a setting member to be mounted and an operating member that operates in cooperation with the setting member and is operated at the other end of the lever member. It was solved by.

[0006]

【Example】

 FIG. 1 shows the construction of an embodiment of an image forming apparatus in which the fixing device 15 of the present invention is implemented. Hereinafter, description will be given with reference to the drawings.

In FIG. 1, reference numeral 1 denotes a lower frame of the image forming apparatus, and a half-moon-shaped paper feed roller 2 for feeding the recording paper P is provided in the lower frame 1 and a plurality of the recording papers P are built-in. The sheet feeding cassette 3 is detachably attached to the lower frame body 1. A push-up plate 4 that is pushed up is provided in the paper feed cassette 3. The recording papers P are fed one by one from the paper feed cassette 3 by an appropriate separating means. Reference numeral 5 denotes a conveyance roller for the recording paper P provided on the lower frame 1, and is provided between a guide plate 6 for guiding the leading end of the recording paper P fed by the paper feed roller 2 and a reversing guide plate 7. .

Reference numeral 8 is a guide plate for guiding the recording paper P to the registration rollers 9 after the recording paper P is reversed and fed, and guides the recording paper P to the registration rollers 9. Reference numeral 10 is a guide plate that guides the recording paper P passing through the registration roller 9 toward the transfer belt 11. The transfer belt 11 is suspended by the transfer roller 13A, the rollers 12 and 13, and the drive roller 14. . Reference numeral 15 is a fixing device for fixing the image transferred onto the recording paper P, which includes a fixing heating roller 17 and a pressure contact roller 1.
6, a roller 18 for uniformizing silicon oil, which also serves as a cleaning agent, is pressed against the fixing heating roller 17, and cleaning is performed according to the rotation. Reference numeral 19 denotes a paper discharge roller for discharging the recording paper P from the fixing device 15. The discharged recording paper P is a recording paper guide member 20, a guide passage 21 formed in the upper frame 1a, and guide conveying rollers 22, 23. Thus, the recording paper P is ejected to the paper ejection tray 24 provided on substantially the entire upper surface of the upper frame 1a. Next, a photosensitive drum 25 for image formation is provided in the substantially central portion of the upper frame 1a, and four developing devices 26, 27, 28, 29 are arranged along the surface of the photosensitive drum 25 from the top. It is the developing device frame 30 that can be installed. A polygon mirror 31 reflects the laser light emitted from the laser light source 32 by the reflection mirrors 33, 34, and 35 to expose the photosensitive drum 25. Reference numeral 36 denotes an optical system frame body integrally incorporating optical systems such as the polygon mirror 31, the reflection mirrors 33, 34 and 35, which is incorporated in the uppermost part of the upper frame body 1a.

Reference numeral 37 denotes a strip electrode for charging the entire surface of the photosensitive drum 25, which is provided on a frame body 42 provided on a part of the upper frame body 1a. A cleaning blade 38 is provided for cleaning the residual toner adhering to the surface of the photosensitive drum 25 after transferring the image from the photosensitive drum 25 to the recording paper P. The cleaning blade 38 is provided on the frame 42 to receive the cleaned toner. A conveying device 39 for discharging the toner to the outside is provided, and a toner receiving member 40 that efficiently sends the developing agent scraped off by the cleaning blade to the conveying device 39 is provided below the cleaning blade 38. Reference numeral 41 denotes a toner replenishing device that supplies color toner and black toner to the developing devices 26, 27, 28 and 29, respectively, and is appropriately fixed to a part of the upper frame 1a. There is only one set, but four sets are provided side by side, and cyan, magenta, yellow, and black toners, for example, are supplied to the developing devices 26, 27, 28, and 29 to perform color development and black development. I am configuring. The lower frame 1 and the upper frame 1a are assembled around the support shaft 1b so that the conveyance path of the recording paper P can be opened. When at least the fixing device 15 is not reached, the upper frame 1a can be opened centering on the support shaft 1b, and the recording paper P can be taken out. The photosensitive drum 25 is provided on a frame body 42 having a cleaning blade 38 via a support shaft 25a, and the support shaft 25a is pivotally supported on the upper frame 1a.

Reference numeral 1c denotes an opening / closing lid that can open a part of the upper frame 1a when replenishing the toner replenishing device 41 with each color toner from the outside.

Reference numeral 41 is a toner replenishing device, 52 is a support shaft to which a toner stirring member is fixed, 54 is a handle operated when replenishing the toner to the toner replenishing device 41, and 55 is a toner to the developing devices 26, 27, 28, 29. It is a supply port for sending

The fixing device of the present invention will be described in detail below with reference to FIGS.

The fixing device 15 is composed of a frame 151. The frame 151 supports a heat source 17D formed in a rod shape, and the heat fixing roller 17 is attached to the frame 151 via a bearing (not shown). The heat source 17D is provided so as to penetrate and heat the heat fixing roller 17. On the other hand, movable frames 162, 163 pivotally mounted on a shaft 161 are provided on a part of the frame 151, and a pressure roller 16 for pressing the recording paper P onto the heat fixing roller 17 is rotatably attached to the movable frames 162, 163. Set up. The movable frames 162 and 163 are provided with springs 164 and 164A, respectively, and the pressure contact roller 16 is pressed against the heat fixing roller 17.

Reference numeral 165 denotes a coating member for coating the surface of the pressure contact roller 16 with silicone oil, the tip of which is brought into contact with the pressure contact roller 16 using a material such as felt that can be impregnated with silicon oil. Reference numeral 166 is a roller for contacting the pressure contact roller 16 to make the amount of silicone oil applied to the surface of the pressure contact roller 16 by the applying member uniform, and is made of a soft material such as felt. A cleaning member 167 cleans the surface of the pressure contact roller 16. Reference numerals 168 and 168A denote intermediate levers for adjusting the pressure bonding force of the pressure contact roller 16 provided on the frame 151, and are rotatably supported by a shaft 169 on a part of the frame 151. Protruding actuating pins 170, 170A are provided at one ends of the intermediate levers 168, 168A, and are inserted into actuating recesses 162A, 163A formed in a part of the movable frames 162, 163. In FIG. 2, springs 171, 171A stronger than the springs 164, 164A are provided so that the intermediate levers 168, 168A always rotate clockwise. 172 and 172A are provided with a shaft 17 on a part of the lower frame body 1.
A spring 173A is provided so as to rotate the operating rods 172 and 172A in the clockwise direction by the operating rod which is rotatably provided at 3. 174 and 174A are operators for operating the operation portions 175 and 175A formed at the other ends of the operation rods 172 and 172A, and fixed to the shaft 176. On the other hand, a cleaning member 17A is provided on the heat fixing roller, and a separating claw 17B is provided on the paper discharge side of the recording paper so as to be contacted by a spring 17C. Reference numeral 152 is a guide plate for guiding the recording paper P to the fixing device 15. 177 and 177A are release levers fixed to the shaft 176 and for releasing the operators 174 and 174A.

The fixing device 15 of the present invention is configured as described above.

FIG. 2 shows a state in which a normal plain paper P is used, and a shaft (176) is rotated by a lever (not shown) provided outside the lower frame body 1 of the image recording apparatus. As described above, the operating elements 174, 174A are released from the operating portions 175, 175A provided on the operating rods 172, 172A. Therefore, the operating rods 172 and 172A are largely rotated clockwise by the spring 173.

Therefore, since the regulation of one end of the intermediate levers 168 and 168A is released, the intermediate levers 168 and 168A are rotated clockwise by the strong springs 171 and 171A. Therefore, the operating pins 170 and 170A provided integrally with the intermediate levers 168 and 168A come into contact with the lower ends of the operating recesses 162A and 163A formed in the movable frames 163 and 162, and the movable springs 163 and 162A are moved by the strong springs 171 and 171A. Press down strongly. Therefore, the pressing roller 16 is pressed against the heat fixing roller 17 together with the springs 164 and 164A by a normal pressing force. In this state, the recording paper P is sent between the pressure roller 16 and the heat fixing roller 17 to heat-fix the toner image. In this state, even if the fixing device 15 is detached from the main body of the apparatus, the tips of the intermediate levers 168 and 168A and the tips of the operating rods 175 and 175A do not abut.

In FIG. 3, the shaft 176 is rotated counterclockwise by a lever (not shown) as described above, and the operating members 174, 174A hit the operating portions 175, 175A provided on the operating rods 172, 172A as shown. The parts 176A and 176B are brought into contact with each other.

By this operation, the operating rods 172 and 172A rotate counterclockwise against the spring 173S, and one ends of the operating rods 172 and 172A press the other ends of the intermediate levers 168 and 168A. Therefore, the intermediate levers 168 and 168A rotate counterclockwise about the shaft 169 against the strong springs 171 and 171A. By this operation, the actuating pins 170, 170A are separated from the lower ends of the actuating recesses 162A, 162B of the movable frames 162, 163 and released from the elastic force of the strong springs 171, 171A, so that the movable frames 162, 163 are springs 164, 164A. Only elastic force is used. In this way, the pressure contact roller 16 provided on the movable frames 162 and 163 weakens the pressure contact force against the surface of the heat fixing roller 17, and the nip width is also reduced. When such an operation is completed, the thick recording paper P is fed between the pressing roller 16 and the heat fixing roller 17 in order to fix the toner image formed on the thick recording paper P, for example, an envelope or the like. The image can be heat-fixed.

However, in the state shown in FIG. 2, when the fixing device is taken out from the lower frame body 1 which is the main body of the device in the arrow Y direction, the tip ends of the intermediate levers 168 and 168A face the operating rods 172 and 172A. The taper surfaces 168B and 168C of the intermediate levers 168 and 168A can be taken out smoothly, but once the fixing device 15 is taken out to the outside, one end of the intermediate levers 168 and 168A is released and the strong spring 171, 168A is released. The 171A makes a large clockwise rotation. When the fixing device 15 is again loaded on the lower frame 1 in the direction of arrow X while holding the operating rods 172 and 172A in the state shown in FIG. 2, the tips of the intermediate levers 168 and 168A are fixed to the shaft 176. The release levers 177 and 177A hit the tip in the direction shown by the arrow, and the operators 174 and 174A rotate clockwise together with the release lever. Therefore, the operating rods 172, 172A are completely released from the operating elements 174, 174A and returned to the position shown in FIG. 1 by the elastic force of the spring 173A, so that the intermediate levers 168, 168A do not hit the operating rods 172, 172A. The fixing device 15 can be arranged at a fixed position.

[0021]

[Effect of device]

 Since the present invention is configured as described above, it has the following effects. That is, when the recording paper P, which is a normal plain paper, is thermally fixed in the fixing device, the pressure contact roller 16 and the heat fixing roller 17 are pressure-bonded with each other with a predetermined pressure, and the pressure bonding force also forms the nip width with a predetermined width. , Forms a good fixed image. When fixing thick recording paper P, the pressure force between pressure contact roller 16 and heat fixing roller 17 can be reduced by one operation, and even thick recording paper P such as an envelope can be smoothly pressed between pressure contact roller 16 and heat fixing roller 17. And the toner image is heat-fixed with an appropriate pressure force, so the image quality is not deteriorated. Further, according to the present invention, even if the fixing device is attached to or detached from the main body of the apparatus during the above-mentioned operation, the operation lever or the like is prevented from hitting, and the fixing device can be installed safely and securely.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an image forming apparatus embodying the present invention.

FIG. 2 is a configuration diagram showing a normal use state of a fixing device.

FIG. 3 is a configuration diagram illustrating a state in which thick paper of the fixing device is used.

[Explanation of symbols]

 1 Lower frame 1a Upper frame 11 Transfer belt 12 Roller 13 Roller 13A Transfer roller 14 Drive roller 14A Drive roller shaft 14B Drive roller surface 15 Fixing device 25 Photosensitive drum 26, 27, 28, 29 Developing device 30 Developing device frame Body 36 Optical system frame 41 Toner supply device 162A, 163A Actuating recess 162, 163 Movable frame 164, 164A Spring 168, 168A Intermediate lever 170, 170A Actuating pin 171, 171A Strong spring 172, 172A Operating rod 174, 174A Operating element 177 Release lever

Claims (2)

[Scope of utility model registration request] 1. A fixing device for fixing a toner image formed on recording paper by heat fixing, a heat fixing roller having a built-in heat source, a pressure contact roller for pressure contact of the recording paper, which is opposed to the heat fixing roller, and the pressure contact. A movable frame that pivotally supports the roller and is pivotally attached to a part of the fixing device frame; and a first spring member that is provided in a part of the movable frame to press the heat fixing roller against the pressure contact roller. A lever member pivotally attached to the fixing device frame, one end of the lever member for moving the movable frame is held against a part of the movable frame, and the heat fixing roller is connected to the heat fixing roller via the movable frame. A second spring member provided on the lever member for pressing the pressing roller, an operating member for operating the other end of the lever member and biased to one side, and a constant force against the biasing force of the operating member. A setting member for setting the position, An image forming apparatus having a fixing device characterized by Tsu preparative member conjunction with the activated provided an actuating member operated by the other end of the lever member. 2. The image forming apparatus having a fixing device according to claim 1, wherein the actuating member is operated by the other end of the lever member when the fixing device is mounted on the image forming apparatus from above.