JPH07234626A - Image heater - Google Patents

Abstract

PURPOSE:To make fixing performance in the axial direction of a heat fixing device uniform by providing a wind path for this heat fixing device with ribs along a direction intersecting with air flow and changing the opening areas of the regions segmented by these ribs in an air flow direction. CONSTITUTION:The wind path 20 for the heat fixer is internally provide with the ribs 20b along the direction intersecting with the air flow direction between louvers 20a. A fan 51 is tight contact with an aperture 52a at one end of an air duct 52 and an aperture 52c at the other end of the air duct 52 is tight contact with the aperture at the side face of the wind path 20 fir heat fixing device. The fan 51 discharge the air in the machine when a main body starts image recording, by which the remaining heat generated from the heat fixing device 10g and the steam (b) generated at the time of passing of recording paper S through the heat fixing device 10g are sucked up from the louvers 20a. The length, i.e., opening area, of the louvers 20a is set longer toward the downstream side of the air flow by a discharge fan 51. The remaining heat and steam sucked up from the respective louvers 20a are evenly discharged by disposing the ribs 20b between the respective louvers 20a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image heating apparatus preferably used as a fixing device for an image forming apparatus such as a copying machine, a printer, a facsimile and the like.

[0002]

2. Description of the Related Art Conventionally, it has been used in a facsimile machine,
In an image recording apparatus for fixing a recorded image on a recording medium such as recording paper by a heat fixing device, the heat fixing device 10g is arranged in proximity to the recording paper discharge roller 10h as shown in FIG. Some are located below the unit 50.

[0003]

However, in the above-mentioned conventional example, when the recording sheet S'passes through the thermal fixing device 10g,
The generated residual heat and water vapor are obstructed by the transmission document reading unit even if they rise upward due to natural convection, and heat accumulation and water vapor condensation occur inside the machine. As a countermeasure against this, if the air is forced to flow in the axial direction of the thermal fixing device 10g with respect to the thermal fixing device 10g to discharge the residual heat and water vapor,
There is a drawback that an axial temperature gradient is generated in the fixing roller, which causes a difference in fixing ability on the fixing roller.

[0004]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention relates to a heating member for heating an image on a recording material, a cover member having a plurality of openings for covering the upper part of the heating member, and an upper part of the cover member. In an image forming apparatus having an air flow forming means for forming an air flow in a direction intersecting a moving direction of a recording material, a rib extending along a direction intersecting the air flow direction is provided on the cover member, and the rib is divided by the rib. The opening area of the formed region is changed in the air flow direction.

[0005]

8 to 10 show a facsimile which is an image forming apparatus using the image forming apparatus of the embodiment of the present invention as a fixing device.

Reference numeral 1 is an apparatus main body, 2 is an original placing table on which the upper surface of the apparatus main body 1 can be stacked with a plurality of upper originals S, 3 is an image reading unit for reading image information of the original S,
Reference numeral 4 is a recording unit including a laser beam printer, 5 is a document conveying unit, 6 is a document pressing unit, 7 is a contact image sensor,
Reference numeral 8 is a document discharge tray, 9 is a laser scanner, 10 is an image forming unit, 11 is a cassette paper feeding unit, 12 is a recording paper discharge tray, 13 is a multi-recording paper cassette, 14 is a cartridge cover, 15 is an ADF cover, 16 is an upper manuscript guide, 1
Reference numeral 7 is a weight shaft, 18 is a document pressing plate, 19 is a lower document guide, 20 is a cover member that forms an air passage for a heat fixing device, 21 is a control unit of a facsimile apparatus, 22 is a telephone receiver, 23 is a conveyance guide, and 24 Is an operation unit, 25 is a display unit, 26 is a lamp indicating the operating state of the facsimile apparatus, 27 is a second stage cassette unit, 28 is a light cover, 29 is a multi-recording paper cassette sensor, and 30 is a multi-recording paper separating unit. .

A slider 2a is slidable on the original table 2 in a direction perpendicular to the conveying direction of the original S (width direction of the original S).
Is provided so that both sides of the original document S stacked on the original document table 2 can be aligned by the slider 2a. If the original S is a long original, the extension original tray 2b can be opened to prevent the rear end of the original S from protruding from the original table 2 and hanging down.

The image reading unit 3 feeds and separates the originals S stacked on the original placing table 2 one by one by a pre-conveying roller 5b in pressure contact with the pre-conveying pressing piece 5a and a separation roller 5d in pressure contact with the reverse rotation roller 5c. Then, the paper is fed to the contact image sensor 7 by the paper feed roller 5f which is pressed against the paper feed roller 5e pressed by the pressing spring 5k, and the original S is moved by the weight pressing shaft 17 and the original pressing plate 18 at the original pressing portion 6. After the image information of the document S is read while pressing the contact type image sensor 7 so as to be in close contact with the contact type image sensor 7, the document S is transferred to the document discharge tray 8 by the discharge roller 5h which is in pressure contact with the discharge roller 5g pressed by the pressing spring 5k. It is designed to be discharged. During this time, the document S is guided by the upper document guide 16 and the lower document guide 19.

The recording section 4 emits a modulation signal from the laser beam oscillator 9a of the laser scanner 9 based on the image signal output from the control section 21, and the modulated beam is reflected by the polygon mirror 9b to the photoconductor of the image forming section 10. The drum 10a is irradiated with scanning light to form image information on the surface of the photosensitive drum 10a, and the image information is fed from the cassette sheet feeding unit 11, the second stage cassette unit 27, or the multi-feeding cassette unit 13 to the image forming unit 10. After the image information is transferred and fixed on the recording paper S ′, it is discharged to the recording paper stack tray 12.

The photosensitive drum 10a is integrally incorporated in the recording cartridge 10a together with the primary charger 10b, the developing roller 10c, and the cleaning roller 10d, and is detachably attached to the apparatus main body 1. Then, the surface of the photosensitive drum 10a is uniformly charged by the primary charger 10b, and when the scanning light is reflected on the surface of the polygon mirror 9b and reflected by the folding mirror 9c, a latent image is formed, and the latent image is formed on the developing roller. The toner is supplied from 10c so as to be visualized.

A transfer charger 10f is arranged around the photosensitive drum 10a of the image forming section 10, and a thermal fixing device 10 is provided in a recording paper conveying path downstream of the photosensitive drum 10a.
g, a paper discharge roller 10h are arranged.

After the toner image formed on the surface of the photosensitive drum 10a is transferred to the recording paper S'by the transfer charger 10f,
The toner image is conveyed along the conveyance guide 23, the toner image is fixed by the thermal fixing device 10g, and the toner image is ejected to the recording paper ejection tray 12 by the ejection roller 10h.

The MP cassette section 13 is arranged at the bottom of the apparatus main body 1. The recording sheets S ′ loaded on the MP cassette 13a are pressed against the MP separation roller 30a by the MP contact plate 13c being rotated upward by the pressing member 13b, and separated one by one by the MP separation pad 30b (friction). (One-side separation method), is conveyed along the MP separation base 30c, and further is conveyed by a conveyance roller 28a, a cover-side U-turn guide 28b arranged on the light cover 28, and a main-body-side U-turn guide 28c arranged on the apparatus main body 1 side. Flipped by Further, the leading edge position of the recording sheet S'which is being fed is detected by the registration sensor 28d, and the feeding and image output timings are adjusted so that the leading edge of the toner image formed on the photosensitive drum 10a and the leading edge of the recording sheet S'match. After being combined, the sheet is conveyed between the transfer charger 10f and the photoconductor drum 10a. The image is recorded on the lower surface side of the recording paper S ′ loaded on the MP cassette 13a.

Further, the recording paper S'is restricted in its side end surface and rear end surface by an MP restricting plate 13d mounted so as to be movable according to the size of the recording paper so that skewing and non-feeding do not occur. The size and presence / absence of the recording paper S ′ are detected by the MP cassette sensor 29. The maximum number of recording sheets that can be stacked is 100, and the recording sheets are pulled out to the left side toward the apparatus main body 1 (side loading method). In addition, there are three types of recording paper sizes that can be stacked: A4, Letter, and Legal. In FIG.
3d is set to A4 size.

The cassette paper feed unit 11 is arranged so that the top plate 11h of the cassette paper feed unit 11 is in contact with the bottom lower surface of the apparatus main body 1, and the top surface of the top plate 11h is the bottom plate of the apparatus main body 1. There is. The recording sheet S ′ stacked in the sheet feeding cassette 11a has an intermediate plate 11e biased upward by an intermediate plate spring 11f, and a semicircular sheet feeding roller 11b and a pair of separating claws 11b.
The recording sheets S ′ are separated one by one by the d (claw separation method), and the separated recording sheets S ′ are conveyed by the cassette conveying roller pair 11c, pass between the MP separation base 30c and the sheet passing guide 28e, and are conveyed by the conveying rollers. 28a, the cover side U-turn guide 28b arranged on the light cover 28, and the main body side U-turn guide 28c arranged on the apparatus main body 1 side. From this point, it is the same as the sheet feeding from the MP cassette unit 13 described above. The paper path joins immediately before the transport roller 28a. The image is recorded on the lower surface side of the recording paper S ′ stacked in the paper feed cassette 11a.

Although not shown in FIG. 10, the second-stage cassette paper feeding unit 27 has almost the same structure as the illustrated cassette paper feeding unit 11, and the recording paper S'in the second-stage cassette 27a is a cassette. Paper is fed to the recording unit 4 through the lateral space 11g of the paper feeding unit 11.

Each of the cassettes 11a and 27a is capable of stacking 500 recording sheets, and is configured to be pulled out to the front side of the apparatus main body 1 (front loading system). In addition, the stackable recording paper size is A
There are two types, letter and letter.

The cassette paper feeding unit 11 and the second-stage cassette paper feeding unit 27 can be separately separated and combined as an option, and the total number of sheets of recording paper that can be stacked on the apparatus is 10.
It is possible to change from 0 to 1100 sheets.

The apparatus body 1 is provided with a cartridge cover 14 which can be opened and closed. By opening the cartridge cover 14, the recording cartridge 10e can be opened.
It can be pulled out and replaced. Further, the cartridge cover 14 is provided with an interlock mechanism so that the recording unit 4 does not operate when the cartridge cover 14 is open or the recording cartridge 10e is not set in the apparatus main body 1. Also,
The drum photosensitive prevention shutter 10i provided on the recording cartridge 10e is designed to interlock with the setting of the recording cartridge 10e to the apparatus main body 1. When the cartridge cover 14 is opened and the recording cartridge 10e is set to the apparatus main body 1, the shutter is released. 10i is opened, and when the recording cartridge 10e is taken out from the apparatus main body 1, the shutter 10i is closed to prevent unnecessary exposure of the photosensitive drum 10a.

When a jam occurs during recording, the cartridge cover 14, the light cover 28, the paper discharge cover 1
The recording sheet S'retained inside can be taken out by opening either 0j or the jam release cover 11i. Further, the paper discharge cover 10j needs to be opened after removing the recording paper discharge tray 12.

The cover member 20 forming the air passage for the heat fixing device is a duct for separating the image reading unit 3 and the recording unit 4, and the heat generated from the recording unit 4 is generated by letting air flow by a fan (not shown). As a result, the image reading unit 3 is prevented from being adversely affected, and water vapor evaporated from the recording paper S ′ is prevented from being condensed and dripping onto the recording paper S ′.

The contact type image sensor 7 has an L as a light source.
The image information surface of the original S is irradiated with light from the ED array, and the reflected light reflected from the image information surface is focused on the sensor element by the SELFOC lens to read the image information.

FIG. 11 is a block diagram of a control system 300 of a facsimile apparatus using the LBP according to the present invention.
In the figure, 301 is a C for controlling the entire facsimile apparatus.
R is a PU that is used as an MPU 311, a ROM 312 that stores a control program for the MPU 311, a work area for various data processing, and a temporary storage unit for image information.
An AM 313, an image processing unit 314 that performs image scaling, resolution conversion, and the like are configured. Also, the CPU 301
Is equipped with a calendar and clock function of known configuration, and the area of the RMA 313 that stores one-touch keys, such as destination information and system setting information, which is important for software switch information, is protected from an unexpected failure such as power failure due to battery backup. Protected. The control system of the facsimile apparatus includes the above-mentioned CPU 301 and the following elements 30.
2 to 310 are connected through an interface.

The operation unit 302 comprises various switches such as a ten key 314, a function key 315, a one-touch key 316, a start key 317, a stop key 317, and the like. The display unit 303 is an LC that displays various messages.
Various LEDs 31 for displaying D318, transmission mode, etc.
9. A tally lamp 320 for notifying a distant operator of the communication status and the occurrence of a failure. The reading unit 304 includes a driving unit 321 such as a reading motor, and a reading sensor 3 that reads an image.
22, an image processing unit 323 that performs shading and binarization of the read image, various sensors 324 that perform document detection, and the like. The recording unit 305 is a drive unit 32 such as a recording motor.
5, a laser scanner, a recording unit 326 for controlling the electrophotographic process, an image processing unit 327 for smoothing an image to be recorded, and various sensors 328 for detecting recording paper and the like. The communication control unit 306 for making a call, receiving a call, encoding image data, and the like has a connection unit 329 including DSU, NCU, and the like, and a communication network 307 and a handset 308 are connected to the connection unit 329. The CPU external interface 309 is an interface for directly transmitting and receiving data from the CPU 301, for example, RS232C, SCS.
The device is used as a scanner printer or the like of an external computer by connecting to a computer external to the device via I, LAN or the like. The HDD 310 is used as a large-capacity non-volatile memory for storing image information and the like.

Next, the basic operation of the laser beam printer section will be described with reference to FIG. 12, which is a conceptual diagram. In FIG. 12, 400 is a semiconductor laser that blinks a laser beam for image data to be recorded, 401 is a polygon motor, 402 is a polygon mirror rotated by the polygon motor 401,
Reference numeral 403 is an optical system for performing image formation and tilt correction, 404 is a photodetector, 405 is a folding mirror, 406 is a photosensitive drum, 407 is a developing device, 408 is recording paper, 409 is a conveyance guide, and 410 is a fixing device.

In the above structure, first the semiconductor laser 4
The laser beam emitted from 00 is deflected by being reflected by the polygon mirror 402, and is irradiated onto the photosensitive drum 406 via the optical system 403 and the folding mirror 405 (main scanning). At this time, the photo detector 404 cuees to determine the irradiation position. While this main scan is completed for one line, the photosensitive drum 406 rotates for one line (sub-scan). The image formed on the photosensitive drum 406 as described above is developed by the developing device 407, and the recording paper 4
08 is transcribed. Further, it is conveyed along the conveyance guide 409, fixed by the fixing device 410, and discharged.

Incidentally, the photosensitive drum 406 and the developing device 40 described above.
Elements of the sub-scanning system such as 7, the conveyance guide 409, and the fixing device 410 are controlled by a recording motor, a gear, a belt, etc.
It is driven in synchronization.

Next, with reference to FIGS. 1, 2 and 3, the thermal fixing device air passage 20 will be described in detail. FIG. 1 is a view best showing the constitution of the embodiment of the present invention, FIG. 2 is a cross-sectional top view of the constitution from the air passage 20 for the heat fixing device to the fan 51, and FIG. 3 is the heat fixing device 10g to the air duct. It is a side surface sectional view showing composition.

1, 2, and 3, reference numeral 20a denotes a louver provided in the air passage 20 for the heat fixing device. In the air passage, ribs 20b are provided between the louvers 20a along the direction intersecting the air flow direction. The fan 51 is in close contact with the opening 52a at one end of the air duct 52. Two openings 52 are provided at the other end of the air duct 52.
b and 52c are provided, 52b is in close contact with the opening of the main body frame (not shown), and 52c is in close contact with the side opening of the thermal fixing device air passage 20. Although not shown in FIGS. 1 and 2, as shown in FIG. 3, the upper surface of the thermal fixing device air passage 20 is sealed by the bottom surface of the document reading unit 50.

In FIG. 1, when the main body starts image recording, the fan 51 operates so as to discharge the air inside the machine to the outside of the machine. As a result, the heat in the main body is discharged to the outside as shown in a in the figure, and at the same time, the residual heat generated from the heat fixing device 10g and the water vapor b generated when the recording paper S passes through the heat fixing device 10g are louvered. It is sucked up from 20a and discharged to the outside of the machine through the air duct 52 as shown in the figure.

As shown in FIG. 2, the shape of the louver 20a is formed so that the length of the louver 20a is sequentially changed depending on the axial position of the heat fixing device 10g. If all louvers have the same shape,
The amount of air sucked from the louver in the vicinity of the opening 52c of the air duct 52 is the largest, and pressure loss occurs in the thermal fixing device air passage 20 as the distance from the opening 52c increases, and the air is sucked from the louver furthest from the opening 52c. A decrease in the amounts of water vapor and residual heat b causes a temperature gradient in the axial direction of the heat fixing device 10g, but as shown in FIG. 2, the length of the louver, that is, the opening area becomes farther from the opening. That is, the pressure loss is reduced by increasing the length of the exhaust fan 51 toward the downstream side of the air flow,
The heat fixing device 10g absorbs the same amount of residual heat and water vapor b in the axial direction, and the ribs 20 are provided between the louvers 20a in FIG.
By providing b, the residual heat sucked from each louver and the steam b are once retained, and then the air duct 5 is evenly distributed.
Can be sucked into 2.

The opening area in the region divided by the rib is changed in the air flow direction.

As a result, the residual heat and the water vapor b generated in the axial direction of the thermal fixing device 10g are evenly absorbed, and the temperature gradient in the axial direction of the thermal fixing device 10g does not occur. The same fixing performance can be assured even in the direction.

In the above-described embodiment, the system in which the fan discharges the air inside the machine to the outside of the machine has been described, but it is also applicable to the case where the fan blows the outside air into the machine.

In the above embodiment, the length of the louver is changed in order to change the opening area.
The opening area may be changed in order with the opening shape as shown in FIG. Further, as shown in FIGS. 6 and 7, a method may be adopted in which the shape of the louvers 20a is fixed and the interval between the louvers 20a is changed.

Further, the number, width, and height of the ribs 20a may be arbitrarily set according to the characteristics of the heat fixing device 10g and the louver 20a.

[0037]

As described above, according to the present invention, residual heat and water vapor can be released to the outside of the machine without causing a temperature gradient in the axial direction of the heat fixing device even by forced convection using a fan. This has the effect of making the fixing performance in the axial direction of the heat fixing device uniform.

[Brief description of drawings]

FIG. 1 is a perspective view of an image heating apparatus according to an embodiment of the present invention.

2 is a cross-sectional top view of the example shown in FIG.

FIG. 3 is a side sectional view of the example shown in FIG.

FIG. 4 is a cross-sectional top view of another embodiment of the present invention.

5 is a side sectional view of the example shown in FIG.

FIG. 6 is a cross-sectional top view of yet another embodiment of the present invention.

FIG. 7 is a side sectional view of the example shown in FIG.

FIG. 8 is a perspective view of an image forming apparatus using an image heating apparatus according to an exemplary embodiment of the present invention.

9 is a side view of the example of FIG.

FIG. 10 is a sectional view of the example shown in FIG.

FIG. 11 is a control block diagram of a facsimile.

FIG. 12 is a schematic view of a laser beam printer unit.

FIG. 13 is a sectional view of a conventional facsimile.

[Explanation of symbols]

1 Device Main Body 2 Document Placement Table 3 Image Reading Unit for Reading Image Information of Document S 4 Recording Part Consisting of Laser Beam Printer 5 Document Transfer Part 6 Document Pressing Part 7 Contact Image Sensor 8 Document Ejection Tray 9 Laser Scanner 10 Image Forming Part 11 Cassette Paper Feeding Part 12 Recording Paper Discharging Tray 13 MPU (Multi Recording Paper) Cassette Part 14 Cartridge Cover 15 ADF Cover 16 Upper Document Guide 17 Weight Shaft 18 Document Holding Plate 19 Lower Document Guide 20 Air Path for Thermal Fixer 21 Facsimile device control unit 22 Handset 23 Conveyance guide 24 Operation unit 25 Display unit 26 Tally lamp 27 Second stage cassette unit 28 Light cover 29 MP cassette sensor 30 MP separation unit 31 MP cassette protrusion 32 MP cassette handle 33 MP cassette protrusion and recording Contact part of the lower surface of the discharge tray 34 Contact part of the projection of the MP cassette and the discharge cover 35 Release button 50 Transmission original reading unit 51 Fan 52 Duct 53 Rear cover 54 Main frame 101, 102 Conventional facsimile device 103, 104 Conventional Cassette 105 Small-sized recording sheet 106 Large-sized recording sheet 107 Ejection cover 108 Ejection tray 109 Ejected and stacked recording sheets 300 Control system of facsimile device 301 CPU 302 for controlling the entire facsimile device 302 Operation unit 303 Display unit 304 reading unit 305 recording unit 306 communication control unit 307 communication network 308 handset 309 CPU external bus interface 310 HDD 400 semiconductor laser 401 polygon motor 402 rotation by polygon motor That the polygon mirror 403 the imaging optical performs inclination correction, system 404 photodetector 405 folding mirror 406 photosensitive drum 407 developing device 408 the recording sheet 409 conveyed guide 410 fuser

Claims (2)

[Claims] 1. A heating member for heating an image on a recording material,
An image forming apparatus comprising: a cover member having a plurality of openings for covering an upper portion of a heating member; and an air flow forming unit for forming an air flow in a direction intersecting a moving direction of a recording material on the upper portion of the cover member. An image forming apparatus characterized in that a member is provided with a rib along a direction intersecting with an air flow direction, and an opening area of a region divided by the rib is changed in the air flow direction. 2. The image forming apparatus according to claim 1, wherein the air flow forming means has an exhaust fan, and an opening area of the air flow upstream side is smaller than that of the downstream side.