JP2006047647A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To lighten load exerted on a user when performing jamming disposal. <P>SOLUTION: A fixing roller and a pressure roller are turned interlocked with the opening/closing of an apparatus main body cover. When the main body cover is opened, the fixing roller and the pressure roller are turned in a reverse direction to a recording material conveying direction at the time of forming an image. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an image forming apparatus using an electrophotographic system.

  Conventionally, a configuration as disclosed in Japanese Patent Application Laid-Open No. 2002-72750 is known as a device in which a heating roller of a fixing device rotates in reverse during jam processing of an image forming apparatus.

  A conventional thermal fixing device will be described with reference to FIG. The heat fixing device includes a fixing roller 127, a pressure roller 128, a heater 134 that is a halogen lamp as a heating source for the fixing roller 127, a temperature control thermistor 126 for the fixing roller 127, and a fixing roller 127. A separation claw 133 and a fixing entrance guide 130 are provided. In this example, the temperature control thermistor 126 is installed in the non-image area. This fixing device is an example of a central reference that conveys a recording material having an A3 (297 mm) width as a maximum sheet passing size with the sheet passing center of the apparatus as a reference, and a pressing force is 800 N. With this configuration, 50 sheets / minute can be printed with A4 horizontal feed. Such a fixing device is provided with a fixing shutter 132 for the following purposes. When transporting the recording material, the fixing entrance shutter is set to 132a to secure a transport path. During non-conveyance, the fixing entrance shutter is set to 132b to play a role of protecting the user and preventing winding around the fixing roller during jam processing.

Such an image forming apparatus improves usability by providing options such as a sorter and a stapler in the paper discharge unit. For this reason, the jamming process of the fixing device does not pull out the recording material to the fixing paper discharge side but temporarily returns it to the fixing inlet side (transfer side) to remove the recording material. As described above, returning the recording material to the fixing inlet side also has an effect of preventing or reducing the fixing separation claw 133 from being stuck in the fixing roller 127.
JP 2002-72750 A

However, in the above configuration, the jam processing needs to include the procedure shown in FIG.
After the jam occurs, open the outer operation cover.

  If there is no device that rotates the fixing device in the direction opposite to the conveyance direction, the recording material is pulled out from the fixing nip by pulling the recording material to the fixing inlet side (transfer side) by hand force. In a fixing device having a high pressure, if the recording material is pulled out by hand, sometimes the recording material is torn and it may be difficult to handle the jam.

  If there is a device that manually rotates the fixing device in the direction opposite to the conveyance direction, the fixing device is rotated in the direction opposite to the conveyance direction, and the recording material is taken out from the fixing nip. When the fixing device is rotated in the reverse direction, if jammed paper is present, the torque becomes high and it is difficult to rotate it manually.

  An object of the invention according to the present application is to reduce the load of the user during jam processing.

  According to the present application, the above object is to form an image having an opening / closing member for accessing the inside of the apparatus, and a rotating body pair for fixing the image on the recording material while nipping and conveying the recording material carrying the image. In the apparatus, the pair of rotating bodies can be rotated in conjunction with opening / closing of the opening / closing member, and when the opening / closing member is opened, the pair of rotating bodies is in a direction opposite to a recording material conveyance direction during image formation. This can be achieved by rotating the

  As described above, according to the present invention, there is an effect that it is possible to reduce the load during the jam processing of the user.

  Embodiments of the present invention will be described below with reference to the accompanying drawings.

(First embodiment)
A first embodiment of the present invention will be described. In the present embodiment, an example will be described in which the jamming reduction of the user is achieved by rotating the fixing roller in conjunction with opening and closing of the operation cover of the image forming apparatus main body.

  An image forming apparatus used in this embodiment is shown in FIG. In the figure, reference numeral 1 denotes a scanner unit having optical means and scanning means for irradiating and scanning laser light transmitted according to image information. Reference numeral 10 denotes a process cartridge incorporating main image forming means, which is a latent image holding member photosensitive drum 3, a roller charger 4 made of semiconductive rubber, and a developing device for developing toner 6 on the photosensitive drum 3. 5 and a cleaner 8 that removes waste toner from the photosensitive drum 3. The photosensitive drum 3 in the process cartridge 10 rotates in the direction of the arrow. After the surface of the photosensitive drum 3 is uniformly charged by the roller charger 4, the laser beam transmitted from the scanner unit 1 passes through the mirror 2. As a result, an electrostatic latent image is formed on the surface. The electrostatic latent image is supplied with toner by the developing device 5 and is visualized as a toner image.

  On the other hand, the recording material (weighing 64 to 216 g) 12 in the paper feed cassette 11 is separated and fed one by one by the paper feed roller 13, and the fed transfer member 12 is along the upper and lower guides 14, It is conveyed to a pair of registration rollers 15. The registration roller 15 is stopped until the recording material 12 arrives, and the skew of the recording material 12 is corrected by the front end of the recording material 12 coming into contact therewith. Next, the registration roller 15 conveys the recording material 12 to the transfer unit so as to be synchronized with the leading edge of the image formed on the photosensitive drum 3. A paper feed sensor (not shown) is installed near the registration roller 15 to detect a paper passing state, a jam, and the length of the recording material. The recording material 12 conveyed to the transfer unit as described above is given a charge opposite in polarity to the toner from the transfer roller 7 from the back side of the recording material 12, and the toner image formed on the photosensitive drum 3 is recorded on the recording material 12. Transcribed to 12. The recording material 12 to which the toner image has been transferred is conveyed to a fixing device 18 by a conveyance roller 17 and a conveyance guide 16, and the fixing device 18 converts an unfixed toner image on the recording material 12 with heat and pressure. A recorded image is obtained by dissolving and fixing it on top. The recording material 12 after image fixing is selected by a flapper 19, and is discharged to two discharge trays 20 or 21 through each conveyance roller.

The heat fixing device 18 will be described in detail with reference to FIG. FIG. 6 is a cross-sectional view showing a schematic configuration of the thermal fixing device 18. The thermal fixing device 18 includes a fixing roller 27 and a pressure roller 28 that are a pair of rotating bodies, a halogen lamp 32 as a heating source for the fixing roller 27, and a temperature control thermistor 26 that is a temperature detecting means for the fixing roller 27. A separation claw 33 as a recording material shielding means for the fixing roller 27 and a fixing inlet guide 30 are provided. In this example, the temperature control thermistor 26 is installed in the non-image area. This fixing device is an example of a central reference in which a recording material having an A3 (297 mm) width as a maximum sheet passing size is conveyed with reference to the sheet passing center of the apparatus. The heater 32 uses a rated output of 800 W when 120 V is input, and the heater light distribution is also symmetrical with respect to the paper passing standard. The fixing roller 27 is a roller having a diameter of 52 mm and a thickness of 3.0 mm using aluminum as a core, and a PFA release layer 29 is coated on the surface layer. The pressure roller 28 has a silicon sponge elastic layer 31 on a stainless steel core, a PFA resin tube that is a PFA release layer on the surface, and has a diameter of 48 mm and a product hardness of 60 °. The thermal conductivity of 28 is 0.7 × 10 ³ W / ° C · cm, and a nip width of 8.0 mm is created between the roller and the fixing roller by applying a pressure of 800 N with a pressure spring. With this configuration, 50 sheets / minute can be printed with A4 horizontal feed.

  In the following, the jam processing method of this embodiment will be described specifically. As shown in FIG. 2, in the image forming apparatus used in the present embodiment, when the exterior operation cover (opening / closing member) 50 is opened in the arrow direction, the gear 51 integrated with the operation cover 50 rotates in the arrow direction, and the one-way clutch The gear 52 rotates in the direction of the arrow. At that time, as shown in FIG. 3, the fixing gear 53 rotates in the direction of the arrow opposite to that during conveyance of the recording material. As the fixing gear 53 rotates in the direction of the arrow, the jammed paper 54 goes out of the fixing nip in the direction of the arrow as shown in FIG. During normal image formation, the fixing device rotates in the recording material conveyance direction, and the gear 51 is not driven by the one-way clutch gear 52. In this embodiment, the fixing roller is driven 170 mm by opening the operation cover 50. Note that the operation cover 50 is locked so as not to open during image formation.

  FIG. 1 shows the jam processing procedure of this embodiment. When a jam occurs and the exterior operation cover 50 is opened, the fixing device rotates in the direction opposite to the conveyance direction, and the jammed paper 54 is taken out of the fixing nip. Next, the user removes the free jammed paper 54 that has come out of the nip, and the jam processing ends. Note that the jammed recording material is easily removed when the driving distance that rotates in conjunction with opening and closing of the operation cover is equal to or greater than the distance between the recording material separating means 33 for separating the recording material from the fixing roller and the center of the fixing nip. Is preferable.

  As described above, when the exterior operation cover is opened, the fixing roller and the pressure roller rotate in the direction opposite to the recording material conveyance direction during image formation, thereby reducing the load on the user during jam processing. Jam processing can be performed and a stable image can be supplied.

(Second embodiment)
A second embodiment of the present invention will be described. In this embodiment, the fixing device reduces or releases the applied pressure in conjunction with the opening and closing of the operation cover of the image forming apparatus main body, and the fixing roller and the pressure roller are rotated in the direction opposite to the recording material conveyance direction during image formation. An example in which the user's jam processing reduction is achieved will be described.

  In the configuration of the image forming apparatus applied to the present embodiment, the description of the same parts as in the first embodiment is omitted. The difference is that the fixing device has a pressure changing function, and the pressure changing device is linked to the operation cover on the exterior.

  A schematic diagram of the fixing device used in this embodiment is shown in FIG. The interlocking between the pressure change device and the operation cover will be described with reference to FIG. As shown in FIG. 12, when the exterior operation cover 50 is opened, the pressure change means 62 moves in the direction of the arrow, and the pressure change device 60 is driven in the direction of the arrow as the pressure change means 62 moves. As shown in FIG. 7, when the pressing force changing device 60 moves in the direction of the arrow, the cam 61 rotates 90 °, and the pressing force is reduced by widening the space between the fixing roller and the pressure roller as shown in FIG. When the operation cover 50 is closed, the pressurizing force changing means 62 moves in the direction opposite to the arrow, and the pressurizing force changing device 60 is driven in the direction of the arrow in FIG. 8, and the cam 61 rotates 90 °, as shown in FIG. Return to normal pressure. The applied pressure in this embodiment is 800 N in the normal state as shown in FIG. 7, and 100 N in the state where the applied force for rotating the cam by 90 ° is reduced as shown in FIG.

  Since the operation cover 50 and the fixing drive are linked in the same manner as in the first embodiment, the description thereof is omitted.

  FIG. 9 shows the jam processing procedure of this embodiment. When a jam occurs and the exterior operation cover 50 is opened, the pressure applied by the fixing device is reduced, and the fixing roller and the pressure roller rotate in the direction opposite to the recording material conveyance direction during image formation. Next, the user removes the free jammed paper 54 that has come out of the nip, and the jam processing ends.

  As described above, when the operation cover of the exterior is opened, the pressure applied to the fixing device is reduced or released, and the fixing roller and the pressure roller rotate in the direction opposite to the recording material conveyance direction during image formation. Therefore, it is possible to reduce the load of the user during jam processing, to perform reliable jam processing, and to supply a stable image.

The flowchart concerning 1st embodiment of this invention. Sectional drawing of the operation cover and fixing drive concerning 1st embodiment of this invention Schematic of operation cover and fixing drive according to the first embodiment of the present invention. Schematic of the operation cover according to the first embodiment of the present invention. Sectional drawing which shows schematic structure of the image forming apparatus concerning 1st embodiment of this invention. Sectional drawing which shows schematic structure of the fixing device concerning 1st embodiment of this invention. Sectional drawing which shows schematic structure of the fixing apparatus in the normal pressurization state concerning 2nd embodiment of this invention. Sectional drawing which shows schematic structure of the fixing device in the pressurization reduction state concerning 2nd embodiment of this invention. The flowchart concerning 2nd embodiment of this invention. Sectional drawing which shows schematic structure of the fixing device concerning the prior art example of this invention The flowchart concerning the prior art example of this invention The block diagram explaining the interlocking | linkage of the applied pressure change apparatus and operation cover of 2nd embodiment of this invention

Explanation of symbols

27 Fixing roller
28 Pressure roller
50 Operation cover
51 Gear
52 one-way clutch gear
53 Fixing gear

Claims (3)

In an image forming apparatus having an opening / closing member for accessing the inside of the apparatus, and a rotating body pair for fixing an image on the recording material while nipping and conveying the recording material carrying the image,
The pair of rotating bodies can be rotated in conjunction with opening / closing of the opening / closing member. When the opening / closing member is opened, the pair of rotating bodies rotates in a direction opposite to the recording material conveyance direction during image formation. An image forming apparatus.   The image forming apparatus according to claim 1, wherein a pressure applied between the pair of rotating bodies is reduced when the opening / closing member is opened.   2. The image according to claim 1, wherein a driving distance that rotates in conjunction with opening / closing of the opening / closing member is equal to or greater than a distance between a recording material separating unit that separates the recording material from the rotating body and a fixing nip center. Forming equipment.

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