JP2003107958A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device that is equipped with an oil heater for heating silicone oil being a release agent for a heat roller and a transfer material and a thermistor for detecting the temperature of the silicone oil so as to heat the silicone oil, and that is constituted to detect the residual amount of silicone oil without using an oil liquid level sensor for detecting the residual amount of the silicone oil. SOLUTION: In the image forming device, a warning is issued by determining that the oil residual amount is a little when the temperature of an oil temperature detection means does not rise even when a prescribed time elapses after turning on an oil heating heater.

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 for forming an image on a transfer material by applying heat and pressure to a toner image formed on the transfer material with a heating and pressure fixing device, and particularly to heating. The present invention relates to a heating / pressurizing roller provided in a pressurizing device, and an image forming apparatus capable of adjusting the temperature of separated oil for improving the releasability between the roller and the transfer material.

[0002]

2. Description of the Related Art Conventionally, in an image forming apparatus such as a copying machine, a toner image is transferred onto a transfer material by a photosensitive drum, and then heated and pressed by a fixing heat roller using a temperature sensor such as a thermistor. By doing so, image formation is performed.

At this time, the toner is melted due to the image on which the toner has been transferred onto the transfer material passing through the fixing heat roller, so that the heat roller and the transfer material have an adhesive action. There was a possibility that the transfer material would wind around the heat roller.

As a countermeasure, oil such as silicone oil is applied to the heat roller to improve the releasability between the heat roller and the transfer material.

Further, due to the temperature dependence of the viscosity of the silicone oil applied to the heat roller, the amount of silicone oil applied to the heat roller varies depending on the temperature of the silicone oil, and as a result, the transfer material heated and pressed by the heat roller is fixed on the transfer material. The amount of oil on the image was not fixed, and it was difficult to make the glossiness of the output image uniform.

Therefore, it has been attempted to heat the silicone oil to keep the viscosity of the oil constant and to stabilize the coating amount.

[0007]

Conventionally, as a means for detecting the amount of oil remaining in the oil pan that stores the above-mentioned silicone oil, the height of the oil level is detected to determine whether or not there is an amount of oil remaining. It was

Then, a sensor such as a photo interrupter for detecting the height of the oil liquid surface at this time is required.

The present invention has been made in view of the above problems, and when the temperature of the silicon oil is not raised until a predetermined time has elapsed after the oil heater is turned on when the oil temperature is adjusted, the oil remaining amount is An object of the present invention is to provide an image forming apparatus that does not require a sensor for detecting the remaining amount of silicone oil by displaying a warning and determining that the amount is insufficient.

[0010]

Therefore, in the present invention, the image forming apparatus described in any one of the following items (1) to (4) is provided to achieve the above-mentioned goal. Is.

(1) The latent image formed on the photoconductor is developed with toner, the toner image on the photoconductor is transferred onto a transfer material, and then the transfer is carried out by applying heat and pressure with a heat and pressure fixing device. An electrophotographic image forming apparatus that forms an image on a material,
Separation oil applied to the heating / pressurizing roller for improving the releasability between the heating / pressurizing roller and the transfer material provided in the heating / pressurizing fixing device, and separation oil for heating the separating oil. A heating heater and an oil temperature detecting means for detecting the temperature of the separated oil are provided, and a warning is issued when the temperature of the oil temperature detecting means does not rise until a predetermined time elapses after turning on the separated oil heating heater. An image forming apparatus having an oil heater control means for discharging.

(2) The image forming apparatus according to (1), further comprising the oil heater control means for stopping the oil heating by the separated oil heating heater after issuing the warning.

(3) The oil heater control means is provided with a pressure roller heater for heating the heating pressure roller, and stops heating the pressure roller by the pressure roller heater after issuing the warning. The image forming apparatus according to (1) or (2), further comprising:

(4) A counter for measuring the time after turning on the separated oil heating heater is provided, the minimum temperature of the oil temperature is detected after the counter operation in the previous period, and when the predetermined temperature rises from the minimum temperature, The image forming apparatus according to any one of (1) to (3), further comprising an oil temperature rise detection unit that determines that the temperature of the oil temperature detection unit has risen.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Examples) Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 shows a schematic configuration of a digital image forming apparatus as an example of the electrophotographic image forming apparatus according to the present invention.

First, the configuration and operation will be described with reference to the drawings.

The image forming apparatus shown in FIG. 1 has a reader unit 1 on the upper part of the main body of the device and a printer unit 2 on the lower part.

The reader unit 1 includes a document table glass 101 on which documents are stacked, a document pressing plate 102 that presses the stacked documents from above, a light source 103 that illuminates the image surface of the document, and a light source 1.
03, a mirror stand 133 for scanning an original, a plurality of mirrors 104 and lenses 105 for guiding the reflected light from the image surface,
The photoelectric conversion / image processing unit 106 performs photoelectric conversion on the reflected light from the document by the CCD 301 and performs various image processing on the obtained electric signal.

Further, the photoelectric conversion / image processing unit 106 has an image processing function of performing A / D conversion, shading correction, masking correction, scaling, LOG conversion, etc. on the photoelectrically converted electric signal.

Next, the operation of the reader unit 1 having the above configuration will be described.

Documents are stacked on the platen glass 101 with the image surface thereof facing downward, and the document pressure plate 102 holds the document from above.

The mirror stand 133 moves while illuminating the light from the light source 103 to scan the image surface of the document.

The reflected light image from the image plane is reflected by a plurality of mirrors 1.
An image is formed on the CCD 301 of the photoelectric conversion / image processing unit 106 via 04 and the lens 105, and is photoelectrically converted into an electric signal here.

The image signal, which has become an electric signal, is subjected to various image processes and then sent to the next printer section 2.

As shown in FIG. 1, the printer section 2 includes a laser control section 304 for converting an image signal sent from the reader section 1 into a signal for driving a laser, a laser element 108, and a photosensitive drum surface. A polygon scanner 109 that scans with laser light, and a photosensitive drum (photoconductor) 1
An image forming unit including 12 and a fixing unit (heating and pressure fixing device) 120 arranged on the most downstream side are configured as main constituent members.

Further, the above-mentioned image forming section is provided with a photosensitive drum 112 rotatably supported in the arrow direction, and a photosensitive drum 11 arranged around the photosensitive drum 112 in the order of its rotation.
2 a primary charger 113 for uniformly charging the surface, a developing device 110 for developing an electrostatic latent image on the photosensitive drum 112, and a transfer charger 1 for transferring a toner image on the photosensitive drum 112 to a transfer material.
19, a cleaner 116 for removing the transfer residual toner on the photosensitive drum 112, a cleaner blade 117, an auxiliary charger 115 for removing the charge, and a pre-exposure lamp 114 for removing the residual charge.

Further, the developing device 110 includes a developing roller 11
1 is provided, and the developing roller 111 rotates in the opposite direction to the photosensitive drum 112 to develop a toner image on the photosensitive drum 112.

The transfer material on which the toner image is transferred is
The pre-fixing belt 118 conveys the toner to the fixing unit 120, where the fixing rollers (heating and pressing rollers) 121, 1
22 is rotated and pressurized by transporting the transfer material,
Upon receiving heat and pressure, the toner image on the surface is fixed.

Finally, the fixed transfer material is discharged to the paper discharge tray 126 outside the apparatus main body via the conveying roller 123 after fixing.

The feeding / conveying unit for feeding the transfer material has a transfer material conveyance path, and the paper feed cassettes 127 and 128 and the paper feed roller 12 are provided on the most upstream side in the transfer material conveyance direction.
It is provided with a sheet feeding device having 9, 130, conveyance rollers 131, 132, and the like.

In addition to this paper feeding device, a multi-paper feeding device 125 is provided.

Since the multi-paper feeding device 125 has a straight paper feeding path, it is possible to feed various transfer materials having different properties such as material and size to the image forming section.

Next, FIG. 2 shows a block diagram of the image forming apparatus of the present invention.

All the devices are controlled by the CPU 306 in a centralized manner.

The CPU 306 mainly drives the respective loads in the apparatus, collects and analyzes the information of the sensors and the image processing unit 107 and the laser control unit 304 described above, as well as an operation unit 305.
That is, it plays a role of exchanging data with the user interface.

Further, the CPU 306 stores a ROM (not shown) in which programs for executing various sequences related to the above-described image forming sequence and rewritable data that needs to be temporarily or permanently stored. A RAM for storing is connected.

In the RAM, for example, a high voltage set value for the high voltage control unit 312, which will be described later, various data described later, image forming command information from the operation unit 305, etc. are stored.

Data exchange with the shading correction unit 303, the image processing unit 107, the laser control unit 304, and the operation unit 305, which is the first role of the CPU 306, will be described.

The image of the original, which is photoelectrically converted by the CCD 301, is converted into digital image data by the A / D conversion unit 302, which is input to the shading correction unit 303.

In the shading correction unit 303, the CPU
Controlled by 306, the black level offset adjustment and the white level shading correction including the characteristics of the light source 103 are performed on the input image data.

The image data after shading correction is input to the image processing unit 107, and masking correction, scaling, repeat, composition, and various decoration processes (shading, netting, netting, shadowing, etc.) are performed.

The CPU 306, in addition to sending the specification setting value data of each part necessary for these image processing, receives signals from each part, for example, a document image density signal, etc. The laser control unit 304 is controlled to make settings for optimal image formation.

The laser control unit 304 optimally controls the laser on the basis of the definition of the image size for forming an image and the image-processed digital video data, that is, in this apparatus, the laser emission is PWM-processed. The necessary settings are made.

The operation unit 305 obtains information such as a copy magnification and a density set value set by the user, and
Data indicating the state of the image forming apparatus, for example, the number of images to be formed, information indicating whether or not an image is being formed, occurrence of a jam and its location, etc. are transmitted to the user.

Next, the driving of each load in the apparatus and the information collection and analysis of the sensors, which is the second role, will be described.

In this device, motors 31 are provided at various places inside the device.
6, a DC load 317 such as a clutch / solenoid, and various sensors 315 such as a photo interrupter and a micro switch are arranged.

That is, the transfer material is conveyed and each unit is driven by appropriately driving the motor 316 and each DC load 317, and various sensors 315 monitor the operation.

Therefore, the CPU 306 controls the various sensors 315.
The motor control unit 310 controls each motor 316 based on a signal from the DC load control unit 311 and the DC load control unit 311 controls the DC load 3 such as a clutch / solenoid.
17 is operated to smoothly advance the image forming operation.

Further, by sending various high voltage control signals to the high voltage controller 312, various chargers constituting the high voltage unit 318, that is, the primary charger 113, the auxiliary charger 115,
Appropriate high voltage is applied to the transfer charger 119 and the developing roller 111.

Further, the CPU 306 has a third role of controlling the driving of the fixing heaters 320 and 321 and the oil heater 201 by inputting an output signal from the thermistor inside the fixing unit 120.

The above-mentioned fixing rollers 121 and 122 in the fixing unit 120 have fixing heaters 320 and 321 for heating the rollers, and the fixing roller 12 respectively.
An oil heater 201 that heats oil 209 for applying to 1, 122 is built in.

Each heater has a fixing heater control section 31.
3. The ON / OFF control is performed by the oil heater control unit 319.

The fixing heater controller 313 and the oil heater controller 319 are connected to a primary power source 324 as a heater.
Fixing heater controller 313 and oil heater controller 31
9 ON / OF of power supply by triac 606 inside
F is performed.

Further, the upper and lower fixing rollers 121 and 122 have fixing heater thermistors 322 and 323 for measuring the roller surface temperature, and the oil heater 201 has an oil heater thermistor 203 for measuring the surface temperature of the oil heater 201. Silicone oil 2 as fixing oil
An oil thermistor 204 for measuring the temperature of 09 is provided. Based on this temperature data, the CPU 306 causes the fixing heater control unit 313 and the oil heater control unit 31 described above.
Control 9

Next, the area around the fixing unit 120 will be described with reference to FIG.

Fixing heaters (pressure roller heating heaters) 320 and 321 for heating the fixing rollers 121 and 122 are provided inside the fixing rollers 121 and 122.
A halogen heater is generally used for 0 and 321.

ON / OFF of fixing heaters 320 and 321
The control is performed by the CPU 306 via the fixing heater control unit 313 as described above.

Further, the fixing heaters 320 and 321 are turned on / off.
The OFF state is controlled so that the surface temperature of the fixing rollers 121 and 122 becomes the specified temperature based on the temperature measured by the fixing heater thermistors 322 and 323 for temperature monitoring, which are attached in contact with the respective rollers.

Further, for the purpose of improving the releasability of the upper fixing roller 121 and the transfer material, the fixing unit 120 applies silicon oil (hereinafter abbreviated as oil) 209 as a separating oil by the oil applying unit 124. .

The oil application unit 124 has an oil pan 205 for storing the oil roller 208 and the oil 209, and an oil heater (separated oil heating heater) 2 for adjusting the oil temperature for keeping the viscosity of the oil 209 constant.
01, mounting of the oil heater 201, a heater metal plate 202 for indirectly transmitting the heat of the oil heater 201 to the silicon oil 209, an oil heater thermistor 203 for measuring the temperature of the oil heater 201, and an inside of the oil pan 205. An oil thermistor (oil temperature detection means) 204 for measuring the temperature of the oil 209, oil application rollers 206, 207 for applying an appropriate amount of oil 209 to the upper fixing roller 121, and an oil pan 20.
5, a float 328 with an arm for detecting the amount of oil so that the amount of oil 209 in 5 is constant, and an oil amount adjustment sensor 327, and oil 209 that has flowed down from the fixing rollers 121 and 122 are stored. An oil pump solenoid 326 for pumping the oil 209 from the lower oil pan through the pipe 325.

The oil heater 201 has a CPU 306.
The oil heater control unit (oil heater control means) 3
ON / OFF control is performed via 19.

FIG. 5 is a circuit diagram showing one embodiment of the oil heater control section 319 which is the oil heater control means.

The output signals of the oil heater thermistor 203 and the oil thermistor 204 are input to the amplifier circuits 601 and 602 of the oil heater control unit 319, and the A / D conversion units 603 and 604 serve as the oil heater 201 and the fixing oil. The resistance value change of each thermistor according to the temperature change of the oil 209 is converted into a voltage value, and then input to the CPU 306 as a digital value.

The CPU 306 outputs the oil control signal 610 based on this temperature data to control the ON / OFF of the oil heater 201.

Further, the oil heater control section 319 is provided with a primary power source 3 for supplying primary power to the oil heater 201.
24 is connected and the oil control signal 6 from the CPU 306
The triac 606 is driven by 10 to turn ON / OFF the primary power supply.

Further, there is an abnormality detection circuit inside the triac 606, and when the triac is short-circuited, the detection signal 611 is output to the EX-OR circuit 608.

In the EX-OR circuit 608, although the oil control signal 610 is OFF (logic is L),
When the abnormality detection signal 611 is input (logic is H), the output becomes L and the abnormality signal 609 is output to the CPU 306. At the same time, the transistor 607 is turned off and the relay 605 is turned on.
Thus, the primary power supply to the oil heater 201 is forcibly turned off.

Further, the oil heater control section 319 includes the oil heater thermistor 203 and the oil thermistor 2.
When the thermistor is dropped by the signal from 04,
An abnormality detection is performed to detect an abnormal output of each thermistor such as a thermistor disconnection, an abnormal signal is output to the CPU 306, and at the same time, the power supply to the oil heater 201 is forcibly cut off.

Next, the operation of the image forming apparatus of the present invention will be described with reference to the flowchart of FIG.

FIG. 4 is a flow chart of the oil remaining amount detecting sequence of the present invention.

First, the oil temperature To is measured by the oil thermistor 204, and if To exceeds the predetermined oil set temperature Tos, the drive of the oil heater is turned off (S502), and the oil temperature To is changed to the oil temperature To. When the temperature is equal to or lower than the set temperature Tos, the oil heater 20
1 is turned on (S503).

When the oil temperature To is higher than Tos and the oil heater 201 is off, the heater on time t
When HON is set to 0 (S510) and To is lower than Tos and To turn on the oil heater 201, a counter 3 for measuring the time provided in the oil heater control unit is set.
29, the counting of the heater on time tHON is started (S504).

Here, tHON when the heater is turned on
The initial value of is 0.

Then, tHON is compared with a predetermined oil rising time tHS (S505).

This oil rise time tHS is the time required from when the oil heater 201 is normally turned on to when the oil temperature rises, and is used to transfer heat from the oil heater to the oil in addition to the wattage of the oil heater. It is determined by the heat capacity of the system including members and the like, and in the case of the present embodiment, it will be described later, but it is necessary to set the time sufficient for the oil temperature to reach ToL + 3 degrees after the oil heater is turned on. .

If tHON has not reached tHS, the oil temperature To and the minimum oil temperature ToL are compared (S506).

Here, the initial value of ToL after the oil heater is turned on is Tos.

If To is lower than ToL, ToL =
As To (S507), the minimum oil temperature ToL is changed.

When To is equal to or greater than ToL, S5
07 is skipped, and it is determined by the oil temperature rise detection means 330 whether or not the oil temperature To has risen (S508).

It should be noted that, here, as the judgment of the oil temperature rise, it is judged that the oil temperature rises when the oil temperature To rises 3 degrees from the oil minimum temperature ToL, and the judgment temperature of rise is set to 3 degrees. In addition to this, it is also possible to change the temperature to the rising determination temperature in consideration of the oil rising time tHS.

That is, the above-mentioned oil rise time tHS is
In the case of the present embodiment, it is necessary to set the time sufficient for the oil temperature to exceed ToL + 3 degrees after the oil heater is turned on.

Then, if it is not confirmed in S508 that the oil temperature has risen, the process returns to S501 again and the above-mentioned oil remaining amount detection control is performed.

This control is repeated, the heater ON time tHON is increased in S504, and tHON is increased in S505.
Has reached tHS, a display such as a low oil level and a warning are issued (S514).

After the warning, the oil heater is turned off to stop the heating of the oil (S515), and the upper and lower fixing heaters 320 and 321 are further turned off to fix the fixing ports 121 and 122.
Heating is stopped (S516).

When it is confirmed in S508 that the oil temperature has risen, the heater ON time tHON is set to 0 (S
510) Returning to S501 again, each time the above-described oil remaining amount detection control is repeated, tHON becomes 0 in S510, tHON in S505 does not reach tHS, and a normal operation without warning is executed.

[0087]

As described above, according to the present invention, in an image forming apparatus for heating silicon oil, which includes an oil heater for heating the silicon oil and a thermistor for detecting the temperature of the silicon oil, the temperature of the silicon oil is increased. During adjustment control, the time after the oil heater is turned on is measured, and if the temperature of the silicon oil does not rise until the predetermined time is reached, it is judged that the remaining amount of oil is insufficient, and a display and a warning are issued. As a result, it is possible to provide an image forming apparatus that does not require a sensor that detects the remaining amount of silicone oil.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a schematic configuration of an image forming apparatus according to an embodiment of the present invention.

2 is a block diagram showing a schematic configuration of a control system of the image forming apparatus of FIG.

FIG. 3 is a schematic cross-sectional view showing a schematic configuration of a fixing device included in the image forming apparatus of FIG.

FIG. 4 is a flow chart for explaining the operation of the release agent temperature control means provided in the release agent coating apparatus according to the embodiment of the present invention.

FIG. 5 is a block diagram showing a schematic configuration of a release agent temperature control means provided in the release agent coating apparatus according to the embodiment of the present invention.

[Explanation of symbols] 1 Reader section 2 Printer section 101 Platen glass 102 original plate 103 light source 133 mirror stand 104 mirror 105 lens 106 Photoelectric conversion / image processing unit 107 image processing unit 108 Laser device 109 polygon scanner 110 developer 111 developing roller 112 Photosensitive drum (photoreceptor) 113 Primary charger 114 pre-exposure lamp 115 Auxiliary charger 116 cleaner 117 Cleaner blade 118 Belt before fixing 119 Transfer charger 120 fixing unit (heat and pressure fixing device) 121,122 fixing roller (heating pressure roller) 123 Conveyor roller 124 Oil coating unit 125 multi paper feeder 126 Output tray 127,128 paper feed cassette 129,130 Paper feed roller 131, 132 Conveyor rollers 201 Oil heater (separated oil heating heater) 202 heater sheet metal 203 Oil heater thermistor 204 Oil thermistor (oil temperature detection means) 205 oil pan 206,207 Oil coating roller 208 oil roller 209 Silicon oil 301 CCD 303 Shading correction unit 304 Laser controller 305 Operation unit 306 CPU 310 Motor control unit 311 Motor load controller 312 High voltage controller 313 Fixing heater control unit 315 sensor 316 motor 317 DC load 318 High voltage unit 319 Oil heater control unit (oil heater control means) 320, 321 Fixing heater (pressure roller heating heater) 322,323 fixing heater thermistor 324 Primary power supply 325 tubes 326 Oil pump solenoid 327 Oil amount adjustment sensor 328 float 329 counter 330 Oil temperature rise detection means 601 and 602 amplifier circuit 603, 604 A / D converter 605 relay 606 Triac 607 transistor 608 EX-OR circuit 609 Abnormal signal 610 Oil control signal 611 detection signal

Continued front page    F-term (reference) 2H027 DA12 DA32 DA39 DE04 DE07                       DE09 EA12 EA15 EC06 EC18                       EC20 ED25 EE01 EE07 EF04                       EF09 EK06 EK09 GA30 GA54                       GB03 GB07 ZA07                 2H033 AA09 AA39 BA25 BA26 BA31                       BA32 BA37 BA44 BA45 BB17                       CA03 CA04 CA06 CA07 CA28                       CA30 CA34 CA57

Claims (4)

[Claims] 1. A transfer material by developing a latent image formed on a photoreceptor with toner, transferring the toner image on the photoreceptor onto a transfer material, and then applying heat and pressure with a heat and pressure fixing device. An electrophotographic image forming apparatus for forming an image on an image forming apparatus, wherein the heating / pressurizing roller is provided in order to improve the releasability between the heating / pressurizing roller and the transfer material. A separation oil to be applied, a separation oil heating heater for heating the separation oil, and an oil temperature detecting means for detecting the temperature of the separation oil are provided, and a predetermined time has elapsed after the separation oil heating heater is turned on. An image forming apparatus comprising: an oil heater control means for issuing a warning when the temperature of the oil temperature detection means does not rise. 2. The image forming apparatus according to claim 1, further comprising an oil heater control unit that stops oil heating by the separated oil heating heater after issuing the warning. 3. An oil heater control means, comprising: a pressure roller heater for heating the heating pressure roller, wherein the heating of the pressure roller by the pressure roller heater is stopped after the warning is issued. The image forming apparatus according to claim 1 or 2, further comprising: 4. A counter for measuring a time after turning on the separated oil heating heater is provided, the minimum temperature of the oil temperature is detected after the counter operation in the previous period, and the oil is increased when a predetermined temperature rises from the minimum temperature. 4. The image forming apparatus according to claim 1, further comprising an oil temperature rise detection unit that detects that the temperature of the temperature detection unit has risen.