JP3900403B2 - Fixing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fixing device that fixes toner on a recording material.
[0002]
[Prior art]
As a fixing device of a printing apparatus known as a laser printer or a copying machine, a recording material holding a toner image is heated and pressed while being nipped and conveyed between a heating roller and a pressure roller, and the toner image is fixed on the recording material. The fixing device is known. Lamps serving as heat sources are provided inside the heating roller. Generally, the number of lamps provided inside the heating roller increases as the printing apparatus has a higher printing speed. In such a heating roller having a plurality of lamps, for example, when the heating roller has reached the end of its life and the heating roller is to be replaced, the lamps are first removed from the heating roller one by one. It is removed from the fixing device and replaced with a new heating roller. Therefore, the number of times of attaching / detaching the lamp to / from the heating roller is required as many as the number of lamps, resulting in poor work efficiency. In order to improve such a problem, for example, a configuration described in JP-T-5-504633 has been proposed. Japanese Patent Laid-Open No. 5-504633 discloses a configuration in which the lamp is pulled out from the rear side of the apparatus with the heating roller attached to the fixing apparatus.
[0003]
[Problems to be solved by the invention]
By the way, as a lamp used in this type of fixing device, there is an elongated lamp having a diameter of about 10 mm and a length of 600 mm or more. In the case of the configuration disclosed in JP-T-5-504633. Because the lamp is exposed to and removed from the heating roller, the lamp surface may be damaged by the edge of the lamp and the heating roller, or contact between the lamp and other parts, or the lamp may be broken. There was a danger that said.
[0004]
An object of the present invention is to simplify the replacement operation of the fixing lamp and to hold the fixing lamp mounted in the heating roller in a correct position without being displaced in the heating roller.
[0005]
[Means for Solving the Problems]
The above-described object is provided with a heating roller having a plurality of fixing lamps therein and a pressure roller provided so as to be capable of being pressed against the heating roller, and adds a recording material holding a toner image to the heating roller. In a fixing device that nippings and conveys the toner image on a recording material while being heated and pressed at a pressure contact portion of a pressure roller, the fixing lamp portion includes a first lamp holder that holds one end of the fixing lamp; and A lamp cartridge having a second lamp holder for holding the other end of the fixing lamp is configured to be detachable from the fixing device main body. When the lamp cartridge is attached to or detached from the heating roller in the fixing device main body , a guide portion for guiding the tubular lamp protective member is attached to the lamp cartridge, in a state of mounting the lamp cartridge to said heating roller There engaged with the first lamp holder, is achieved by providing a regulating member and a regulating portion for regulating the movement in the axial direction and the circumferential direction of the lamp cartridge.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, a laser beam printer using an electrophotographic system will be exemplified as a printing apparatus to which the present invention is applied, and the overall configuration will be described with reference to FIG.
[0007]
In FIG. 9, reference numeral 1 denotes a laser beam printer. The photosensitive drum 21 starts to rotate in the direction of the arrow based on a printing operation start signal from the controller 22. The photosensitive drum 21 rotates at a speed corresponding to the printing speed of the laser beam printer 1 and continues to rotate until the printing operation is completed. When the photosensitive drum 21 starts to rotate, a high voltage is applied to the corona charger 2 and, for example, positive charges are uniformly charged on the surface of the photosensitive drum 21.
[0008]
The rotary polygon mirror 3 starts rotating as soon as the laser beam printer 1 is turned on, and maintains constant speed rotation with high accuracy while the power is turned on. Light output from the light source 4 such as a semiconductor laser is reflected by the rotary polygon mirror 3 and irradiated while scanning the photosensitive drum 21 through the fθ lens 5.
[0009]
When character data or graphic data converted into a dot image is sent from the controller 22 to the laser beam printer 1 as a laser beam on / off signal, the surface of the photosensitive drum 21 is irradiated with the laser beam and the non-irradiated portion. Are formed, and a so-called electrostatic latent image is formed. When the photosensitive drum area holding the electrostatic latent image reaches a position facing the developing device 6, toner is supplied to the electrostatic latent image, and the portion of the photosensitive drum 21 on which the electric charge has disappeared due to the laser beam irradiation, For example, a positively charged toner is attracted by static electricity and a toner image is formed on the photosensitive drum 21.
[0010]
The continuous sheet 7 stored in the sheet hopper 11 is synchronized with the timing at which the toner image of the print data formed on the photosensitive drum 21 reaches the transfer position by the sheet conveying tractor 8 and the transfer unit. 10 is conveyed toward the middle.
[0011]
The toner image formed on the photosensitive drum 21 is sucked onto the sheet 7 by the action of the transfer unit 10 that applies a charge having a polarity opposite to that of the toner image to the back side of the sheet 7.
[0012]
In this way, the paper 7 set in the paper hopper 11 is transported to the fixing device 12 through the paper transport tractor 8, the transfer device 10, the paper transport tractor 9, and the buffer plate 24. The sheet 7 that has reached the fixing device 12 is preheated by the preheater 13, and then is heated by a pair of fixing rollers including a heating roller 14 and a pressure roller 15 having a fixing lamp (hereinafter referred to as “heater lamp”) 25. The toner image is melted and fixed on the sheet 7 while being nipped and conveyed while being heated and pressurized by the formed nip portion.
[0013]
The paper 7 sent out by the heating roller 14 and the pressure roller 15 is sent out to the stacker table 19 side by the paper feed roller 16 and is alternately folded along the perforation by the swinging motion of the swing fin 17. Further, while the folded state is adjusted by the rotating paddle 18, they are stacked on the stacker table 19. The area that has passed the transfer position of the photosensitive drum 21 is cleaned by the cleaning device 20 and is prepared for the next printing operation.
[0014]
In FIG. 9, reference numeral 23 denotes a display screen for displaying information based on the state of the laser beam printer 1 during the printing operation. The buffer plate 24 is for absorbing slack or tension generated on the paper 7 when a paper transport speed difference occurs between the paper transport tractor 9 and the fixing rollers 14 and 15. Reference numeral 26 denotes a web member provided so as to be able to come into contact with the surface of the heating roller 14 and to be wound, for cleaning the surface of the heating roller 14 and applying a release agent to the surface of the heating roller 14. Is.
[0015]
Next, a detailed configuration of an example of the lamp cartridge will be described with reference to FIG. The lamp cartridge 27 includes a plurality of (four in this embodiment) heater lamps 25 for the heating roller 14 described in FIG. 9, and a first lamp holder 28 that holds one end of each heater lamp 25. The second lamp holder 29 that holds the other end of the heater lamp 25 and a protective member holding portion 30 provided around the heater lamp 25 held by the first lamp holder 28. Here, the protection member holding portion 30 is provided to hold the lamp protection member when a lamp protection member to be described later is mounted, and the means is not particularly limited, but in this embodiment, The protection member holding part 30 is formed by the tapered surface.
[0016]
As shown in FIG. 2, the first lamp holder 28 includes a hole 31 for inserting one end of the heater lamp 25 and a hole 32 for inserting the spacer 33. Both the hole 31 and the hole 32 are through holes, and when the heater lamp 25 is inserted into the hole 31, consideration is given so that the power supply line 63 (see FIG. 5) provided in each heater lamp goes out. A spacer 33 is fitted into the hole 32.
[0017]
Each heater lamp 25 is inserted into the hole 31, and each component is fixed with screws 37 so that the lamp holder 28 is sandwiched between the plate 34 and the plate 36. In FIG. 2, reference numeral 35 denotes a spring. The spring 35 is installed in a groove provided on the back surface of the lamp holder 28, and applies a predetermined pressing force to the two heater lamps facing each other to prevent the heater lamp from rattling in the hole 31.
[0018]
FIG. 4 shows the back surface of the lamp holder 28 (a front view as seen from the direction of the screw 37 in FIG. 2). In FIG. 4, reference numeral 38 denotes a groove for installing the spring 35. Reference numeral 39 denotes a recess formed in the front portion of the lamp holder 28. This recess 39 prevents rotation of the lamp cartridge mounted on the heating roller, and 39a controls the axial direction. A restricting member 65 (hereinafter referred to as “lamp holder stopper”) (refer to FIG. 5, FIG. 6 and FIG. 7A) provided on the fixing device main body side is provided on the recess 39 to enter the lamp cartridge. 27, and the lamp holder stopper 65 is retracted from above the recess 39 (see FIG. 7B) so that the restriction of the position of the lamp cartridge 27 in the axial direction and the circumferential direction is released.
[0019]
On the other hand, the 2nd lamp holder 29 is provided with the hole 40 for inserting the other end of the heater lamp 25, and the hole 41 for inserting the spacer 42, as shown in FIG. Similarly to the first lamp holder 28, the hole 40 and the hole 41 are both through holes, and when the heater lamp 25 is inserted into the hole 40, the power supply line 63 (see FIG. 5) provided in each heater lamp is outside. It is considered to come out. A spacer 42 is fitted into the hole 41. Each heater lamp 25 is inserted into the hole 40, and each component is fixed with a screw 45 so that the lamp holder 29 is sandwiched between the plate 43 and the plate 44. If necessary, a spring may be provided in the same manner as the first lamp holder 28.
[0020]
Next, the configuration around the heating roller in a state where the lamp cartridge is mounted will be described with reference to FIG.
[0021]
The heating roller 14 is composed of, for example, a metal base tube 14a made of aluminum and a surface layer 14b made of Teflon, silicon rubber or the like provided on the base tube 14a, and an absorber for preventing heat release at both ends of the base tube 14a. 14c is provided. Both ends of the raw tube 14 a are supported by the frame 50 of the fixing device via holding members 48 and 49 having centering members 46 and 47. Here, the holding member 48 is provided with a bearing 51, and the bearing 51 is coupled to the heating roller 14 together with the centering member 46. Further, the bearing 51 is arranged so that the plurality of springs 52 and the guide plate 53 can absorb the thermal expansion of the heating roller 14 and the variation of the surrounding support members. Note that the holding member 48 and the frame 50 are fixed by a thumbscrew 54.
[0022]
On the other hand, the holding member 49 is provided with a gear 55 that receives a driving force from a driving motor (not shown) for driving the heating roller 14 and includes bearings 56 and 57 attached to the frame 50. It is supported by two types of housings 58 and 59. Further, the centering members 46 and 47 are provided with projections 60 for ensuring the coupling with the heating roller 14 and engage with grooves 61 provided at both ends of the heating roller 14.
[0023]
Further, in order to prevent heat from flowing from the heating roller 14 to the centering members 46 and 47 and damage at the engaging portion between the protrusion 60 and the groove 61, the protrusion between the both ends of the heating roller 14 and the centering members 46 and 47 is provided. A collar 62 made of heat-resistant plastic is inserted except for the portion 60. In FIG. 5, a line denoted by reference numeral 63 drawn from both ends of the lamp cartridge 27 is a power supply line for the heater lamp 25.
[0024]
In the above configuration, the lamp cartridge 27 is inserted from the through hole 48a provided in the holding member 48 and mounted in the heating roller 14 as shown in FIG. Here, the reason why the shapes of the first lamp holder 28 and the second lamp holder 29 are different is to prevent erroneous insertion of the lamp cartridge 27.
[0025]
When the lamp cartridge 27 is pulled out from the heating roller 14, the operator goes to the rear side of the printing apparatus (the side where the second lamp holder 29 exists), and the lamp is inserted through the through hole 59a provided in the housing 59 as shown in FIG. The cylindrical member 64 which is a protective member is inserted and pushed in until the tip inner peripheral surface of the cylindrical member 64 is held by the tapered surface 30 provided in the first lamp holder 28.
[0026]
When the setting of the cylindrical member 64 is completed, the operator moves to the front side of the printing apparatus, retracts the lamp holder stopper 65 from the recess 39 (see FIG. 4) of the lamp holder 28 (see FIG. 7), and The restriction of the position in the axial direction and the circumferential direction is released. When the lamp cartridge 27 is pulled out from this state, the lamp cartridge 27 and the cylindrical member 64 are pulled out together and taken out to the outside in a state as shown in FIG.
[0027]
Further, when inserting the lamp cartridge 27 into the heating roller 14, to move the lamp holder stopper 65 in the state of FIG. 7C, the front side of the printing apparatus of the cartridge in the state shown in FIG. 8 the tubular member 64 of the lamp holder stopper 65 guide The portions 65a, 65b, and 65c are inserted as guides. At this time, the lamp cartridge 27 can be prevented from being damaged due to interference with the portion 14c in the heating roller 14 of FIG. After the insertion is completed, the lamp holder stopper 65 is moved onto the concave portion 39 of the first lamp holder 28 (see FIG. 7A) to restrict the position of the lamp cartridge 27. After that, when moving to the rear side of the printing apparatus and pulling out the tubular member 64, the mounting is completed.
[0028]
The cylindrical member 64 is deteriorated at both ends 64a in FIG. 8 every time the lamp cartridge 27 is repeatedly replaced. The 64a portion is reinforced to reduce the deterioration, and the means is not particularly limited. In the example, an adhesive is applied to form 64a.
[0029]
【The invention's effect】
As described above, according to the present invention, when the fixing lamp is attached to and detached from the heating roller, the fixing lamp is protected by the lamp protection member, so that the fixing lamp can be attached and detached efficiently and safely. Since the fixing lamp mounted in the heating roller is held in the correct position without being displaced in the heating roller, the range of the heat generation area in the axial direction of the heating roller is stabilized, and overheating or underheating It is possible to reduce the fixing failure due to. In addition, the deterioration of the lamp protection member due to repeated attachment and detachment of the fixing lamp can be reduced, and further, by having a guide when the fixing lamp is mounted, damage to the fixing lamp due to erroneous insertion can be reduced.
[Brief description of the drawings]
FIG. 1 is an overall perspective view of a lamp cartridge of the present invention.
FIG. 2 is an overall perspective view of a first lamp holder.
FIG. 3 is an overall perspective view of a second lamp holder.
FIG. 4 is a rear view of the first lamp holder.
FIG. 5 is a cross-sectional view of a heating roller.
FIG. 6 is a cross-sectional view showing a state where a lamp protection member is inserted into a heating roller.
FIG. 7 is a front view showing an operation state of a lamp holder stopper.
FIG. 8 is an overall perspective view of a lamp cartridge to which a lamp protection member is attached.
FIG. 9 is an overall configuration diagram of a printing apparatus.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 25 ... Fixing lamp, 27 ... Lamp cartridge, 28 ... 1st lamp holder, 29 ... 2nd lamp holder, 30 ... Protection member holding part, 64 ... Lamp protection member, 64a ... Lamp protection member reinforcement part, 65 ... Lamp Holder stopper (regulating member).

Claims (2)

A heating roller having a plurality of fixing lamps therein and a pressure roller provided so as to be capable of being pressed against the heating roller, and a recording material holding a toner image is pressed between the heating roller and the pressure roller In a fixing device for nipping and conveying the toner image on a recording material while being heated and pressed by a fixing member, the fixing lamp portion includes a first lamp holder for holding one end of the fixing lamp, and the other end of the fixing lamp. A lamp cartridge having a second lamp holder for holding the lamp cartridge is configured to be detachable from the fixing device main body. The fixing device main body has a lamp cartridge attached to the lamp cartridge when the lamp cartridge is attached to and detached from the heating roller. a guide portion for guiding the tubular lamp protective member is attached, the said lamp cartridge in a state mounted on the heating roller first Lamp holder and engaged, a fixing device, characterized in that a regulating member and a regulating portion for regulating the movement in the axial direction and the circumferential direction of the lamp cartridge. The fixing device according to claim 1, in the first lamp holder, a fixing device, characterized in that a protective member holding portion for holding said lamp protective member.

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