JPH0683228A - Image forming device - Google Patents

Abstract

PURPOSE:To always smoothly and uniform apply a release agent and to form high-grade images free from striae and unequalness on transferred images by constituting a metering blade in such a manner that its position in the axial direction of an applying roller can be moved. CONSTITUTION:The metering blade 4 is energized under a specified pressure to the applying roller by an energizing spring and is moved in the axial direction of the oil applying roller by a driving source while the metering blade 4 is held pressed under the specified pressure to the applying roller by a cam 8 moving in the axial direction of the applying roller and an energizing spring 9. While the metering blade 4 is held pressed under the specified pressure to the applying roller 2 by the energizing spring driven by a cam 6, the metering blade is moved in the axial direction of the applying roller roller by driving of the cam 8. Namely, the movement of the metering blade 4 is repeated by driving of the cam 6, by which the dust, toner powder, etc., sticking to the edges of the metering blade are removed and the applying striae and unequalness are eliminated.

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 such as an electrophotographic copying machine or an electrostatic recording device.

[0002]

2. Description of the Related Art Conventionally, a releasing agent such as silicone oil (hereinafter referred to as oil) is used for a fixing roller in an image forming apparatus.
As a method of applying the oil, a method of applying oil to the fixing roller with a felt, a method of pumping the oil with a felt and applying the oil to the fixing roller via the applying roller, and the like have been put to practical use. However, in the case where the oil is supplied to the fixing roller or the application roller by the felt as described above, the oil supply amount becomes uneven due to the surface roughness of the felt or the dirt, and therefore, in the traveling direction of the recording material. Parallel oil streaks remained on the recording material, damaging the image.

In order to eliminate the oil streaks, as shown in FIG. 5, a fixing device has been proposed in which a scooping roller is used to scoop up silicone oil. In FIG. 5, P is an oil pan in which a release agent such as silicone oil O is stored, 1a and 1b are a scooping roller pair immersed in the oil O in the oil pan P, and 2 is a scooping roller pair 1a and 1b. Application rollers that are always in contact with each other, 3, 3a are fixing rollers, and 4 is a metering blade for regulating the amount of oil on the application rollers.

The pumping rollers 1a, 1b and the coating roller 2 are driven to rotate in the direction of the arrow in the figure by a drive source (not shown) to pump up the silicone oil O in the oil pan P. The coating roller 2 is a drive source (not shown).
Is configured to reciprocate around the rotation center 11 together with the scooping rollers 1a and 1b to contact and separate from the fixing roller 3. Normally, when the recording material enters the fixing device at the chain line position in the figure, the application is performed. The roller 2 contacts the fixing roller 3 to apply the silicone oil O to the fixing roller 3. Further, the metering blade 4 has a spring 7 so that a constant pressure is always maintained against the coating roller 2.
It is urged by and regulates the amount of oil applied.

Next, FIG. 15 shows another conventional apparatus. In this conventional example apparatus, the recording material P is passed through the nip portion between the fixing roller 101 and the pressure roller 102 to heat and melt and fix the unfixed toner image on the recording material P.

Then, a release agent 10 such as silicone oil
It is widely practiced to apply 3 to the surface of the fixing roller 101 by the release agent applying means 104 to prevent the offset of the toner 105.

FIG. 16 shows an electrophotographic full-color image forming apparatus in which such a fixing device 110 is mounted. 16, four image forming stations Pa, Pb, Pc, Pd are arranged in the image forming apparatus, and each image forming station Pa, Pb, Pc, Pd is a photosensitive drum 106a, 106b, 106c, 106d as an image carrier. And a dedicated charging means 107a,
107b, 107c, 107d, exposure means 108a, 108b, 108c, 108d such as a laser scanner, developing means 109a, 109b, 109c, 109d, transfer means 111a, 111b, 111c, 111d, cleaner means 112a, 112b, 112c, 112d. Each is arranged. Here, the image forming station P
a, Pb, Pc, and Pd are for forming a yellow image, a magenta image, a cyan image, and a black image, respectively.

On the other hand, each of the image forming stations Pa to Pb
An endless belt-shaped conveying means 113 is arranged below the photosensitive drums 106a to 106d so that the recording material P such as paper fed by a sheet feeding roller 114 is conveyed by the conveying means 1
13, the transfer means 111a to 111d of the image forming stations Pa to Pd transfer the developed images of the respective colors formed on the image forming stations onto the recording material P.

When the four color toner images are superposed on the recording material P, the recording material P is separated from the conveying means 113 and heated and fixed by the fixing means 110 to obtain a full color image.

In such a full-color image, the rotation of each image carrier is uniformly stabilized in order to match the registration of each color image and prevent color misregistration. The conveying speed of the recording material by the conveying means is made uniform. The image writing timing is controlled in each image forming station. The magnification of the exposure unit, the exposure position, and other optical conditions in each image forming station are matched. Etc. are taken. Further, in the transfer section of the recording material from the conveying means 113 to the fixing device 110, both recording material conveying means are made to coincide with each other.

Next, a conventional apparatus using a transfer drum as the transfer means will be described. In this conventional example device, a drum-shaped photoconductor for forming a separated color transfer image according to image information and a multi-transfer of the separated color transfer image onto a recording material (generally plain paper) are held. And a recording material fed from a storage unit such as a cassette, is synchronized with the separated color transfer image formed on the photoconductor by using a registration roller, and a predetermined amount on the transfer drum. The image is transferred by being conveyed to a position, and after that, it is separated from the transfer drum and the transfer image is fixed by the fixing unit.

In the above apparatus, the transfer drum unit is constructed so as to be attachable to and detachable from the main body of the apparatus in consideration of operability of paper jam. Further, a plurality of sensors are provided on the recording material conveying roller in order to confirm the feeding state of the recording material.

Further, recently, there is also a device in which the transfer drum and the fixing device are mounted on the same frame and can be pulled out toward the front side at the same time to further improve the processing operability and serviceability when a paper jam occurs. is there.

Further, for the purpose of downsizing the entire apparatus, the distance from the transfer point where the transfer drum and the photoconductor contact each other to the fixing roller nip is set to be shorter than the maximum size of paper that can be passed, and the leading end of the paper is fixed. In some devices, there is a case in which the transfer is still in progress at the trailing end at the time of entering the nip.

[0015]

However, according to each of the above conventional examples, there are the following problems. First, according to the conventional example shown in FIG. 5, there is a problem of oil streaks on the transferred image due to dirt on the metering blade. The amount of silicone oil applied is determined by regulating the amount of oil pumped up using the metering blade biased by the spring against the application roller as described above, and at the same time, the application roller is applied. Apply smooth and evenly on top.

According to this structure, a uniform and desired coating amount can be obtained in the initial state, but with the lapse of time, the edge portion of the metering blade becomes dirty, specifically, paper dust and toner. There is a problem in that it is not possible to form a uniform oil application over the entire axial direction of the application roller due to powder, lint, dust, and the like.

That is, in a portion where there is a deposit such as dust, the application of oil is hindered, or a gap is formed between the application roller and the metering blade portion, and as a result, the oil on the surface of the application roller is There is a problem in that application unevenness results in oil streaks on the transferred image and application unevenness, which significantly deteriorates the image quality.

Further, according to the conventional example shown in FIG. 16, it is difficult to make the conveying speeds of the conveying means and the fixing device coincide with each other, and when the conveying speed of the fixing device 110 is lower than the conveying speed of the conveying means 113, the fixing is performed. Since the recording material is pulled by the rollers, that is, the image during the transfer process has a high conveyance speed of the recording material, so that the image becomes an extended image and color misregistration occurs.

Therefore, the conveying speed of the fixing device 110 is slightly slower than the conveying speed of the conveying means 113, and the conveying means 1
A color shift is prevented by forming a loop in the recording material at the transfer portion between the image forming apparatus 13 and the fixing device 110.

However, the amount of the loop is also limited, and if the loop becomes too large, the recording material will come into contact with the charging device or other members in the vicinity, causing problems such as image rubbing. Therefore, the transport speed of the fixing device 110 needs to be maintained at a speed that is slightly lower than the transport speed of the transport means 113 and that is smaller than a certain loop amount of the recording material.

However, what determines the conveying speed of the fixing device 110 is the rotation speed of the fixing roller, the nip amount of the fixing roller, the diameter of the fixing roller, the rubber hardness of the fixing roller, etc.
, Includes the problem of variation between fixing roller parts or between machines, and swelling of the fixing roller due to oil over time, and the transport speed of the fixing device was properly adjusted at the factory at the beginning. Even when the fixing roller is replaced or changes depending on the endurance state of the fixing roller, the fixing roller is out of the proper transport speed range, and as a result, problems such as color misregistration or image rubbing occur.

Further, in the conventional apparatus having the above-mentioned transfer drum, even if the photosensitive drum and the registration roller pair are accurately positioned between both sides of the image forming apparatus, the transfer drum and the fixing unit are easy to operate and service. In consideration of the characteristics, the user and service personnel can easily attach and detach the nip line of the registration roller pair and the nip line between the photosensitive drum and the transfer drum so that the parallelism with the nip line of the fixing roller pair is not always required. Not guaranteed. Therefore ,. When the nip line of the registration roller pair is deviated from the nip line of the fixing roller pair, the timing at which the leading edge of the recording material enters the fixing roller varies depending on the location, and paper wrinkles or skew may occur on the recording material. ． When the nip line between the photosensitive drum and the transfer drum is misaligned with the nip line of the fixing roller pair, the transport directions of the two are slightly different, and when a long recording material is transported in the transport direction, the leading end of the recording material is fixed to the fixing roller. In a device in which the trailing edge of the recording material is still being transferred at the time of entering the pair, the conveyance direction shifts, which may adversely affect the image. That is, for example, when a multicolor image is transferred, only the final color is affected by the above, which may cause color misregistration.
In particular, when a multicolor image is transferred, a transfer deviation of the order of micron appears as a color deviation, so that the allowable range of the deviation is limited as compared with the case of a single color.

The first object of the present invention is to solve the above-mentioned problems and to apply a release agent to the fixing roller constantly and evenly.
An object of the present invention is to provide an image forming apparatus without oil streaks and unevenness.

A second object of the present invention is to solve the above-mentioned problems and to provide an image forming apparatus capable of adjusting the conveying speed of the fixing device regardless of the state of the fixing device. .

Further, a third object of the present invention is to solve the above problems, stabilize the transportability of the recording material from the transfer section to the fixing section, and prevent image distortion such as color misregistration on the image forming apparatus. Is intended to provide.

[0026]

According to the first invention of the present application,
The first object is a fixing roller for fixing an unfixed toner image formed on a recording material through a predetermined process on the recording material, and a scooping roller arranged so as to be immersed in a release agent. An application roller which is arranged so as to come into contact with the scooping roller and which applies release to the fixing roller, and a meter which is arranged so as to come into contact with the application roller and which regulates the amount of release agent applied on the application roller. In the image forming apparatus having a ring blade, the metering blade is arranged so that the axial position of the coating roller with respect to the surface of the coating roller is variable.

Further, according to the second invention of the present application, the second object is to provide a plurality of image bearing members each having an unfixed developer image of a different color on its surface, and an endless member facing each image bearing member. Recording material conveying means having a movable surface and sequentially conveying the recording material to the facing portion of each image carrier, and transfer means for transferring the unfixed developer image onto the recording material at the facing portion. An image forming apparatus having a fixing means for sandwiching and conveying the recording material on which the unfixed developer image of each color is transferred and fixing the developer image on the recording material, and detecting the recording material conveying speed of the fixing means. A speed detection unit and a drive control unit for the fixing unit are provided, and the drive control unit is set so as to correct the recording material conveyance speed of the fixing unit to an appropriate value based on the speed detected by the speed detection unit. It is achieved by

Further, according to the third invention of the present application, the above second object is to provide a plurality of image bearing members each carrying an unfixed developer image of a different color on its surface, and an endless end face opposed to each image bearing member. Recording material conveying means having a movable surface and sequentially conveying the recording material to the facing portion of each image carrier, and transfer means for transferring the unfixed developer image onto the recording material at the facing portion. In an image forming apparatus having a fixing unit for sandwiching and conveying a recording material on which an unfixed developer image of each color is transferred and fixing the developer image on the recording material, a recording material conveying speed of the recording material conveying unit is set. A first speed detecting means for detecting, a second speed detecting means for detecting a recording material conveying speed of the fixing means, and a drive control means for the fixing means, the drive control means comprising:
This is achieved by setting the recording material conveying speed of the fixing means to be equal to the recording material conveying speed of the recording material conveying means based on the detection speeds of the first and second speed detecting means.

According to the fourth invention of the present application, the third object is to provide an image carrier for carrying a transferred image on the surface thereof, and a recording material for holding the recording material, which is arranged so as to face the image carrier. Holding means, holding means, transfer means for transferring the transfer image on the image carrier to the recording material on the recording material holding member, and a pair of rollers rotatably arranged in pressure contact with each other, the recording material is nipped and conveyed. In the image forming apparatus having a fixing device for fixing the transferred image on the recording material, the fixing device is achieved by the position of the pressure contact portion of the roller pair being movably attached.

[0030]

In the first invention of the present application, the release agent on the coating roller is regulated by the metering blade so that the coating amount on the fixing roller is maintained at a predetermined amount. Moreover, since the metering blade is arranged so as to be movable in the axial direction of the coating roller, the contact position with respect to the coating roller is changed to remove dust, toner powder, etc. adhering to the end of the metering blade. Eliminate. In this way, uniform and smooth oil application can be performed without causing application stripes and application unevenness.

Further, in the second invention of the present application, when the recording material is conveyed by the recording material conveying means to the position where the respective image carriers and the recording material conveying means face each other, the respective colors of the respective colors carried on the respective image carriers are conveyed. The unfixed developer image is transferred onto the recording material by the transfer means, and the recording material is guided to the fixing means. And
The fixing means nip-conveys the guided recording material and fixes the unfixed developer image on the recording material. At this time, the fixing unit is set to convey the recording material at an appropriate speed, but this speed changes with time due to swelling or the like caused by the release agent. Therefore, the speed detecting means detects the recording material conveying speed of the fixing means, and the fixing means is driven while correcting the speed so as to maintain an appropriate value. As a result, a good fixing operation without color misregistration is performed.

Further, according to the third invention of the present application, in addition to the recording material conveying speed detecting means of the fixing means similar to the second invention, a recording material conveying speed detecting means of the recording material conveying means is provided,
The fixing means drives the fixing means by comparing the conveying speed and the conveying speed of the recording material conveying means so that both speeds become equal.
Thus, the recording material is smoothly transferred from the recording material conveying means to the fixing means, and a good fixing operation without color misregistration is performed.

Further, according to the fourth aspect of the present invention, since the fixing device is movably attached to the position of the pressure contact portion of the roller pair, for example, the pressure contact portion is adjusted according to the recording material guided to the roller pair. By moving and adjusting the recording material, the recording material can smoothly enter the pressure contact portion, and wrinkles, color misregistration, and the like can be prevented.

[0034]

Embodiments 1 to 6 of the present invention will be described with reference to the drawings.

<First Embodiment> First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view showing the main part of the device of this embodiment. In FIG. 1, P is an oil pan 1a containing a release agent such as silicone oil O,
1b is a pumping roller, 2 is an oil applying roller, 3 and 3
Reference numeral a is a fixing roller, and 4 is a metering blade.

The metering blade 4 has a central axis of rotation 5
The blade 7 is rotatable about the center of the coating roller 2 and is biased by the blade biasing spring 7 against the coating roller 2 at a constant pressure. 6
Is a cam for moving the metering blade. This cam moves the position with respect to the surface of the coating roller in the roller axial direction (thrust direction) at regular intervals (in the direction of the arrow in the figure).
Is a cam for the drive source (not shown),
It is driven in synchronization with the rotation of the oil application roller.

The pumping roller 1b is always in the oil pan P.
Is immersed in the silicone oil O in the inside thereof, and the scooping roller 1a, for applying the silicone oil to the fixing roller 3,
1b, when the coating roller 2 rotates, the pumping roller 1
It is pumped up on a and 1b and applied through the oil application roller 2. The timing of application is set in accordance with the timing at which the recording material passes through the fixing device.

FIG. 2 shows in detail the positional relationship between the metering blade 4 and the oil applying roller 2.
The metering blade 4 is urged to the application roller at a constant pressure by the urging spring 7, and the metering blade 4 is applied to the application roller at a constant pressure by the application roller axial movement cam 8 and the urging spring 9. While being in contact, the drive source (not shown) moves the oil application roller in the axial direction, that is, in the direction of the arrow in the figure.

FIGS. 3A and 3B show the positional relationship between the metering blade 4 and the oil application roller 2 in the roller axial direction. The metering blade 4 is brought into contact with the coating roller 2 at a constant pressure by the urging spring 7 by the driving of the cam 6, while the cam 8 is driven by the cam 8 in the axial direction of the coating roller surface. That is, it moves in the direction of the arrow.

In other words, by driving the cam 6, FIG.
By repeating the movement of the metering blade 4 from the state of Fig. 3 (b) to the state of Fig. 3 (b), it becomes possible to remove dust, toner powder, etc. adhering to the edge portion of the metering blade. At the same time as the occurrence of coating streaks and coating unevenness is eliminated, uniform and smooth oil coating can be performed while maintaining a desired coating amount.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIG. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 4 is a side view showing the main part of the device according to the second embodiment of the present invention. In FIG. 4, P is silicone oil O
Oil pans 1a and 1b that store release agents such as 1 are pumping rollers, 2 are oil coating rollers, 3 and 3a are fixing rollers, and 4 is a metering blade.

In this embodiment, 10 is metering.
An actuator for moving the blade axial direction, for example, a stepping actuator using a stepping motor or the like. Further, 9 is an urging spring, which is driven by the actuator 10 to meter the coating roller.
By moving the position of the blade 4 in the axial direction of the coating roller in the direction of the arrow, it is possible to prevent oil streaks and unevenness as in the first embodiment. The actuator 10 is driven by a control device (not shown) at regular intervals or at regular time intervals to remove dust, paper dust, toner dust, etc. that cause oil streaks and unevenness.

In this embodiment, a cam and an actuator are described as an example of the means for moving the metering blade in the coating roller axial direction, but the means for moving the metering blade is limited to the moving means having the above-mentioned configuration. Of course, any suitable means, such as solenoids, clutches, etc., may be selected.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 6 is a cross-sectional view showing a schematic configuration of the device of Example 3 of the present invention. This fixing device includes a fixing roller 101, a pressure roller 102 facing the fixing roller 101, a release agent applying unit 104 for applying a silicone oil 103 as a release agent to the fixing roller 101,
A cleaning unit 116 for cleaning the fixing roller 101 is provided.

In the fixing roller 101, an elastic layer 118 made of HTV silicone rubber (high temperature vulcanizing silicone rubber) is formed on a core metal 117 usually made of aluminum as a base material, and an offset prevention layer 119 is formed thereon. The outer diameter is, for example, 40 mm.

The pressure roller 102 includes an elastic layer 12 made of HTV silicone rubber on a core metal 120 made of aluminum.
1, and the resin layer 12 of fluororesin is formed on the elastic layer 121.
2 is formed, and similarly, the outer diameter is, for example, 40 mm.
It is said that.

A halogen heater 123 is provided in the core metal 117 of the fixing roller 101 and the core metal 120 of the pressure roller 102.
The temperature of the pressure roller 102 is detected by the thermistor 124 in contact with the pressure roller 102, the halogen heater 123 is controlled to be turned on and off, and the fixing roller 101 and the pressure roller 10 are controlled.
The temperature of 2 is kept constant at about 170 ° C.

The release agent applying means 104 is a silicone oil 103 having a viscosity of 300 cs contained in a container 125.
The upper and lower supply rollers 126a and 126b are scooped up and applied to the offset prevention layer 119 of the fixing roller 101. The amount of silicone oil applied to the offset prevention layer 119 is adjusted by the contact angle and pressure of the oil amount adjusting blade 127 that is brought into contact with the upper supply roller 126a.

The cleaner means 116 is the fixing roller 101.
The toner offset to the offset prevention layer 119 is removed.

According to the fixing device as described above, the recording material P carrying a plurality of unfixed toner images T stacked thereon is carried by the carrying device in the direction of arrow a, and the recording material P is driven by the driving device ( (Not shown) is passed between the fixing roller 101 and the pressure roller 102, which are rotated in the direction of arrow b, while sandwiching them so that the stacked toner images T are mixed on the recording material P and thermally fixed to form a full-color image. Let it form.

Then, the fixing roller 101 and the pressure roller 1
A light emitting element 128 and a light receiving element 129 are provided on the downstream side of the fixing nip portion N formed by No. 02. Light emitting element 1
28 and the light receiving element 129 constitute a recording material detecting means for detecting the presence of the recording material P immediately after passing through the fixing nip portion N (hereinafter referred to as a fixing outlet sensor 130).

The fixing outlet sensor 130 constitutes a recording material conveying speed detecting means, and can detect the conveying speed of the recording material P passing through the fixing nip portion N.

In FIG. 7, the fixing roller 101 is the pressure roller 1.
FIG. 6 is a diagram for explaining a change in the transport speed when being pressurized by 02. For example, the fixing roller 101 is deformed by the pressure roller 102, and the fixing nip portion N shown in AB.
When the fixing roller 101 is formed and the fixing roller 101 is rotating at a constant angular velocity, the conveyance speed v of the fixing roller 101 is higher due to the arc AB than when the fixing nip portion N is not formed. This state is shown in FIG.

FIG. 8 shows a fixing roller 10 having a diameter of 60 mm.
1 shows the relationship between the fixing nip width L and the conveying speed v of the fixing roller 101 when the rubber hardness is 60 ° and the rubber wall thickness is 2 mm. For example, the nip width is set to 6.5 mm, and at that time, the conveyance speed v of the fixing roller 101 is 86 mm / sec.
When the nip width L changes by 1 mm, it is 2.3 m
There is a speed change of m / sec.

FIG. 9 shows the amount of swelling (radial displacement) Δr of the fixing roller 101 and the variation ΔL of the fixing nip width.
Shows the relationship with.

Thus, the conveyance speed of the fixing roller changes depending on the nip width. The nip width depends on the swelling amount of the fixing roller 101 as described above, as well as the hardness of the fixing roller or the diameter of the fixing roller. According to the present invention, the fixing outlet sensor 26 detects the fixing roller conveyance speed even if the above-mentioned factors that affect the fixing roller conveyance speed change, and the driving rotation speed of the fixing roller is corrected based on the result. The conveyance speed of the fixing roller is controlled so that it is kept within an appropriate fixed position.

In this embodiment, the image forming process speed is 86 mm / sec, and in this case, the proper conveying speed range of the fixing roller is 84 mm / sec or more and 86 mm / s.
ec or less, that is, 85 mm / sec ± 1 mm / sec
Has become. Therefore, drive control may be performed with the target center value of the conveyance speed of the fixing roller set to 85 mm / sec.

The conveying speed of the recording material by the fixing roller is measured as the time during which the recording material shields the fixing outlet sensor 130. For example, in the case of the recording material size A3 (420 mm), when the time during which the fixing outlet sensor 130 outputs High (fixing outlet sensor output time) is 420/85 = 4.941 sec, it is determined that the target conveyance speed is reached. it can.

Further, the proper conveyance speed range of the fixing roller (84
(mm / sec to 86 mm / sec) is 4.883 sec to 5 sec when converted to the fixing outlet sensor output time.

Next, a method of correcting the conveyance speed of the fixing roller 101 will be described. FIG. 10 schematically shows the fixing roller 101 and its rotation driving means. The rotating shaft 101a of the fixing roller 101 is rotatably supported by the fixing device main body, and a pulley 170 is provided at one end of the roller 101.
Are installed constantly. A stepping motor 171 is arranged near the pulley 170 so that its rotation axis is parallel to the rotation axis of the roller 101.
The pulley 170 is integrally formed with the output shaft of the motor 171.
The pulley 172 is attached so as to make a pair with.
A drive belt 173 is wound between the pulleys 170 and 172, and the fixing roller 101 is rotationally driven at a constant speed along with the track of the motor 171.

On the other hand, the motor 171 has
A stepping motor control circuit 176 that controls a stepping motor drive circuit 175 that drives 71, and a pulse oscillation source 177 that oscillates a drive pulse to rotate the motor 171 at a constant speed are sequentially connected, and the stepping motor control The circuit 176 includes the fixing roller 10
A circuit 179 is connected to calculate the conveyance speed of the recording material P by 1, 102 and correct the speed.

Next, a method of correcting the fixing speed will be described. For example, if the step angle of the motor 171 is 0.72
°, the reduction ratio with the pulley 172 is 1/4, the roller 101,
When 102 is a rigid roller having a diameter of 40 mm, the rotation distance of the roller surface per pulse of the motor 171 is 40 × π × (0.72 ° / 360 °) × (1/4) =
It becomes 0.06283 mm.

Fixing professional speed 86 mm / se
c, the pulse rate of the motor 171 is 86 (mm / sec) /0.06283=1368.7.
It will be 73 pps.

When a crystal oscillator having a frequency of 2 MHz is used as the pulse oscillation source 177, the clock cycle becomes 0.5 / sec. Then, as described above, when the process speed is 86 mm / sec, the set value of the internal timer of the stepping motor control circuit 176 is (0.06283 / 86) ÷ (0.5 × 10 −6) = 1
It becomes 461.2, which is rounded to 1461. That is, when 1461 pulses of the pulse oscillation source 177 are counted, the stepping motor control circuit 176 is provided with one drive pulse. The set value of the internal timer of the stepping motor control circuit 176 is rewritable, and the above "1461" is input as the initial value.

Next, based on FIG. 11, the circuit 1 shown in FIG.
The control of 79 will be described. First, when a predetermined signal is received, the control sequence of the circuit 179 starts (S31 in FIG. 11).

At this time, the internal timer of the stepping motor control circuit 176 is set to the initial value "1461", and the roller 101 is driven based on this initial value. Then, the fixing outlet sensor 26 of FIG.
The time T from the detection of the leading edge to the subsequent detection of the trailing edge is measured (S32).

Then, the measured time T is compared with a regular value, and the set value of the internal timer is rewritten according to the difference. For example, when the regular value of the conveyance speed of the recording material P by the fixing rollers 101 and 102 is 86 mm / sec,
When a recording material of A3 size 420 mm is conveyed, time T
The regular value of is 4.884 sec. Now, the time T
Assuming that the actual measurement value of is 4.773 sec, it is 2.326% later than the regular value. Therefore, the set value of the internal timer is calculated as 1461 × (1−0.02326) = 1427 (S33), and the stepping motor control circuit 1
The internal timer of 76 is rewritten to "1427" (S3
4).

The control sequence of the circuit 179 is first executed, for example, before the factory is shipped. If the above-described control sequence is executed every time a fixed number of sheets are passed, for example, every 1,000 sheets after being installed in the market, it is possible to deal with the change with time of the fixing roller. Further, when the fixing roller is regularly replaced, if the above-mentioned control sequence is executed after the fixing roller is replaced, it is possible to set the dispersion of the fixing roller or the fixing conveyance speed in the initial state of the fixing roller to an appropriate value.

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIGS. In addition, Example 3
The same parts as in FIG.

As shown in FIG. 12, in this embodiment, a detecting means 131 for detecting the conveying speed of the conveying means 113.
And a detection unit 13 for detecting the conveyance speed of the fixing device.
It has two and tries to match the transport speed of the fixing device to the transport speed of the transport means 113.

The detecting means 131 is a reflection type photosensor and outputs High when the recording material is present on the conveying means, and the detecting means 132 is the above-mentioned fixing exit sensor.

FIG. 13 shows that when the recording material is fed, both sensors 1
It is a signal side detected by 31, 132, and it is possible to determine whether the transport speed of the fixing device is faster or slower than the transport speed of the transport unit 113 by observing the magnitude relationship of t ₁ with respect to t ₀ .

For example, when t ₁ is 95% with respect to t ₀ , it means that the conveying speed of the fixing device is 5% faster, which is 5% smaller than the set value of the internal timer of the stepping motor control circuit 176. Just do it. FIG. 15 shows the control flow.

In the above embodiments, the case where the stepping motor is used as the roller drive source of the fixing device has been described, but the present invention is not limited to this, and other drive sources such as a DC motor may be used. good.

Although a belt and a belt pulley are used as the drive transmission means in the description, transmission means such as a gear or a chain may be used.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIGS. In FIG. 17, reference numeral 201 denotes a photosensitive drum that is a photosensitive member that forms a transfer image on the peripheral surface according to image information. Around the photosensitive drum 201, a primary charger 202 for charging the drum peripheral surface, a developing device 204 for visualizing the electrostatic latent image formed by the exposure light beam 203, and a residual toner on the drum surface after image transfer A cleaner 205 for collecting the developed developer (toner) is provided.

When the photosensitive drum 201 is driven to rotate in the clockwise direction, it is charged by the primary charger 202 and then by the exposure light beam 203 containing image information such as reflected light from the original surface (not shown). An electrostatic latent image is formed, and the electrostatic latent image is developed in full color by the developing device 204 to be visualized. The developing device 204 contains toners having respective colors of yellow Y, magenta M, cyan C, and black K, and is configured so that a full-color recording material can be formed by combining toners of respective colors.

Further, around the photosensitive drum 201,
Dielectric sheet 2 such as a high resistance film that holds a transfer medium
Transfer drum 2 as a transfer medium holding member around which 06c is wound.
06 is in contact. Inside the transfer drum 206, a transfer charger 206a for charging the recording sheet 207, which is a transfer medium, to a polarity opposite to that of the transfer image formed on the photosensitive drum 201 is provided. The transfer drum 206 holds a plurality of recording sheets 207 on its peripheral surface and transfers a transfer image from the photosensitive drum 201.

On the upstream side of the transfer drum 206 in the sheet conveying direction, a cassette 208 in which recording sheets 207 are stacked and stored is provided. The recording sheets 207 stacked in the cassette 208 are conveyed from the uppermost one by the feeding roller 209 to the registration roller 211 which is a synchronous conveying means along the guide members 210a and 210b.
At this time, the leading edge of the recording sheet 207 is the registration roller 21.
The skewing is corrected by hitting the nip portion of No. 1. The registration roller 211 moves the recording sheet 20 to the image transfer position in synchronization with the transfer image formed on the photosensitive drum 201.
7 is conveyed. An adsorption charger 206b is arranged inside the transfer drum 206 and electrostatically adsorbs the recording sheet 207 on the dielectric sheet 206c. The adsorption charger 20
An attraction conductive roller 219 serving as a counter electrode is arranged at a position opposite to the outside of the transfer drum 206 with the dielectric sheet 6b interposed therebetween.

On the downstream side of the transfer drum 206, a separation claw 212 for separating the recording sheet 207 from the peripheral surface of the transfer drum 206, a conveying device 213, and a fixing guide 21.
4, a fixing device 215 for fixing the transferred image of the recording sheet 207, a discharge roller 216 for discharging the recording sheet 207 after the image fixing, a recording sheet 207 after discharging
Ejection trays 217 for stacking sheets are sequentially provided. Further, between the transport device 213 and the fixing device 215,
A sheet detection sensor 218 for detecting the leading edge of the recording sheet 207 after the image transfer is provided.

The operation of the image forming apparatus configured as described above will be described. The cassette 208 feeds the roller 209.
The recording sheet 207 fed by is guided to the registration roller and its skew is corrected. The registration roller 21
Reference numeral 1 conveys the recording sheet 207 to the contact portion between the photosensitive drum 201 and the transfer drum 206, which is the image transfer position, in synchronization with the transferred image formed on the photosensitive drum 201. The recording sheet 207 conveyed to the transfer position has the images of the respective colors transferred in a multiple manner, and is separated by the separation claw 212 from the transfer drum 2.
It is separated from 06 and conveyed to the fixing device 215. The fixing device 215 melt-mixes and fixes the toner, which has been multi-transferred onto the recording sheet 207 as it is on the powder, and the recording sheet 207 after the image fixing is discharged to the discharge tray 217 by the discharge roller 216.

Further, in order to improve the operability in the processing such as paper jam and service maintenance, the portion from the transfer drum 206 to the fixing device 215 (the range surrounded by the broken line in FIG. 17) is on the same frame. It is mounted on and is configured so that the whole can be pulled out to the front side.

FIG. 18 is a detailed sectional view of the fixing device 215. In FIG. 18, 220 is a stay of the frame body,
The entire fixing device 215 is supported and fixed thereon. The fixing device 215 is composed of three side plates on one side and six side plates on both sides. 221 (dashed line part) is an upper plate, 222 (solid line part) is a lower plate, and 223 (broken line part) is an inner plate. The lower side plate 222 is fixed to the fixing bottom plate 224, and the upper side plate 221 and the inner side plate 223 are rotatably supported by the lower side plate 222 around pins 225 and 226, respectively. Further, the upper side plate 221 has the fixing roller 227 and the inner side plate 2
Reference numeral 23 supports the pressure roller 228. Upper plate 221
Is fixed to the lower side plate 222 and the inner side plate 223 is supported by a fulcrum 226.
A nip is formed between the fixing roller 227 and the pressure roller 228 by urging clockwise around the center of FIG.

The above-mentioned structure is intended to attach importance to serviceability such as roller replacement. However, only by forming the nip between the fixing roller and the pressure roller, the stay 220 of the frame body to the fixing bottom plate 224 and the lower side plate 222 are formed. , The upper plate 221, the inner plate 223 and several parts are required, and the pin 22 of the fulcrum of rotation is required.
5, 226, fixing, and play of the bearing portion of the pressure roller, it is expected that the nip line formed by the fixing roller and the pressure roller will vary to some extent.

Next, the means for adjusting the fixing nip line, which is the essence of the present invention, will be described. FIG. 19 is a top view of the adjustment unit, and FIG. 20 is a front view of the same. As shown in FIGS. 19 and 20, the frame stay 220 has a pin 229 for positioning the fixing device 215 with respect to the stay 220.
a and 229b are fixed. The pin 229a on the back side is completely fixed to the stay, but the pin 2 on the front side is fixed.
The position of 29b can be adjusted. That is, the pin 229b is fixed to the adjusting plate 230, and the position of the pin 229b on the front side is moved by moving the adjusting plate 230 along the laterally determining long hole 220b provided on the frame stay 220 side. Is determined. In addition to the pin 229b, an elongated hole in the adjustment direction is formed in the adjustment plate 230, and the distance between the reference wall 220c cut and raised from the frame stay 220 and the adjustment plate 230 is adjusted by the adjustment screw 231. After locking the amount with the nut 232, the adjusting plate is fixed to the frame body with the fixing screw 233. The fixed screw 233 may be configured by a step screw so that it can be always moved in the adjustment direction.

On the other hand, a fixing hole is provided on the fixing bottom plate side of the fixing device 215 at a position corresponding to the pin 229a, and the pin 229 is provided.
An elongated hole for adjusting direction is formed at a position corresponding to b, and after fixing the positions of the pins 229a and 229b, the holes of the fixing bottom plate are aligned with the pins 229a and 229b to fix the fixing device to the frame stay 220. Position, that is, the nip line between the fixing roller and the pressure roller is determined. As described above, the above-mentioned adjusting means enables the nip line to be finely adjusted so as to have an angle with respect to the stay of the frame body.

Next, the detection of the line that serves as a reference for adjustment will be described. First, the photosensitive drum 201 and the transfer drum 2
Regarding the nip line with 06, as described in the description of the conventional example, it can be realized by checking the influence on the image of the trailing edge of the recording material that is long in the transport direction. For example,
This is the color shift of the final color in the case of multicolor image transfer. Further, regarding the line of the leading edge of the sheet, the sensors 218 shown in FIG. 17 are provided at a plurality of positions depending on the size of the sheet so that the vicinity of both ends of the sheet can be detected. When the leading edge detection timing of the conveyed sheet differs between the front sensor and the rear sensor, the fixing nip line is adjusted so as to match the approaching direction of the sheet leading edge.

In this embodiment, the adjusting plate, which is the adjusting means for the fixing nip line, is screw-adjusted and then nut-locked and fixed with a screw. However, the adjusting screw is connected to a motor or the like by an electric means. You may drive. In these cases,
For example, the information can be fed back from the paper edge detection sensor to enable automatic adjustment online.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIG. Note that the description of the common points with the fifth embodiment is omitted.

In the fifth embodiment, the adjustment direction of the nip line can be limited to the rotation adjustment within the sheet material conveying surface, but the adjustment direction is set to change the front and back height directions of the nip line. You may. This is, for example,
If the upper curl on the back side tends to be stronger than the front side due to the type of recording material and transfer conditions, you can adjust the height of the back side of the nip line to a position slightly higher than the height on the front side. The leading edge of the sheet into the fixing nip can be facilitated on average over the entire width.

FIG. 21 is a block diagram for performing the above control. The central processing unit (CPU) 241 and the ROM 24 storing the control program for controlling the CPU 241.
2, and a RAM 243 as a main recording device. Further, the CPU 241 has a drive motor 244 that adjusts the rotation of the fixing roller nip line in the horizontal direction in the conveyance plane and a drive motor 245 that adjusts the rotation of the nip line in the conveyance plane in the vertical direction as in the fifth embodiment. Output interface 246 that outputs a control signal to a load such as a recording material type 247 that is input from the operation unit, transfer mode 248, paper size detection 249, and sensor 250 that detects a difference between the front and back positions of the leading end of the sheet material. , Fixing nip line detection sensor 25
An input interface 252 for inputting the detection signal from 1
Connected with.

When the paper edge detection sensor 249 detects a deviation between the line at the leading edge of the sheet and the fixing nip line, the horizontal adjustment drive motor 244 is driven to correct the deviation.

From the information of the recording material type 247, the mode 248, the paper size 249, etc., for example, the height direction adjustment is performed so as to correspond to the expected situation by comparing with the data of the curl situation of the sheet inputted in advance. Drive motor 245
To drive.

[0095]

As described above, according to the first invention of the present application, by making the position of the metering blade in the axial direction of the coating roller movable, the coating line of the release agent coated on the coating roller can be changed. It is possible to prevent coating unevenness, always realize smooth and uniform release agent application, prevent streaks and unevenness on a transferred image, and achieve a high-quality image.

Further, according to the second aspect of the present invention, since the recording material conveying speed of the fixing means is detected and the fixing means is driven so that the speed is kept at an appropriate value, the diameter of the fixing roller and the rubber hardness are determined. It is possible to fix the dispersion and change of the recording material conveying speed of the fixing roller due to the dispersion of the nip amount, the change with time, and the like comprehensively, and always perform the fixing at the appropriate conveying speed. Therefore, pulling the recording material by the fixing roller,
Alternatively, it is possible to prevent excessive loops and solve problems such as image elongation and rubbing.

Further, according to the third invention of the present application, the recording material conveying speed of the fixing means and the conveying speed of the recording material conveying means are detected and the fixing means is driven so that both speeds become equal. Variations and changes in the recording material conveyance speed of the fixing roller due to variations such as roller diameter, rubber hardness, nip amount, and changes over time can be corrected comprehensively, and fixing can always be performed at an appropriate conveyance speed. Therefore, it is possible to prevent the recording material from being pulled by the fixing roller or to prevent an excessive number of loops, and solve the problems such as image elongation and rubbing.

Further, according to the fourth aspect of the present invention, since the fixing device is attached so that the position of the pressure contact portion of the roller pair can be moved and adjusted, it is possible to stabilize the transportability of the recording material and to fix it on the recording material. An image forming apparatus that does not disturb an image can be provided.

[Brief description of drawings]

FIG. 1 is a sectional view showing a schematic configuration of a device according to a first embodiment of the present invention.

FIG. 2 is a schematic view showing a metering blade moving mechanism in the apparatus shown in FIG.

FIG. 3 is a schematic diagram showing a metering blade movement positional relationship in the apparatus of FIG.

FIG. 4 is a cross-sectional view showing a schematic configuration of a device according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a schematic configuration of a conventional device.

FIG. 6 is a cross-sectional view showing a schematic configuration of an apparatus of Example 3 of the present invention.

FIG. 7 is a diagram for explaining the relationship between the nip width and the recording material conveyance speed in the apparatus shown in FIG.

FIG. 8 is a graph showing the relationship between the nip width and the recording material conveyance speed in the apparatus shown in FIG.

9 is a graph showing the relationship between the amount of swelling of the fixing roller and the amount of change in the nip width in the apparatus of FIG.

10 is a diagram showing a schematic configuration of a rotation driving unit of a fixing roller of the apparatus shown in FIG.

11 is a flowchart showing a flow of operations of a drive control circuit in the apparatus shown in FIG.

FIG. 12 is a cross-sectional view showing a schematic configuration of a device of Example 4 of the present invention.

13 is a diagram showing an example of signals detected by a speed detecting unit of a fixing unit and a speed detecting unit of a recording material conveying unit in the apparatus of FIG.

14 is a flowchart showing a flow of operations of a drive control circuit in the apparatus shown in FIG.

FIG. 15 is a sectional view showing a schematic configuration of a conventional fixing device.

FIG. 16 is a cross-sectional view showing a schematic configuration of a conventional image forming apparatus.

FIG. 17 is a cross-sectional view showing a schematic configuration of a device of Example 5 of the present invention.

FIG. 18 is a cross-sectional view showing a schematic configuration of a fixing device in the device of FIG.

FIG. 19 is a top view showing a mounting portion of the apparatus shown in FIG. 18;

FIG. 20 is a plan view of FIG.

FIG. 21 is a schematic flowchart showing a pressure contact portion adjustment operation control of the fixing device in the sixth embodiment of the present invention.

[Explanation of symbols]

1a, 1b Pumping roller 2 Application roller 3 Fixing roller 4 Metering blade O Silicone oil (release agent) 101 Fixing roller (fixing means) 102 Pressure roller (fixing means) 106a, 106b, 106c, 106d Photosensitive drum (image bearing) Body) 111a, 111b, 111c, 111d Transfer means 113 Conveying means (Recording material conveying means) 130 Fixing exit sensor (speed detecting means) 132 Detecting means (first speed detecting means) 131 Detecting means (second speed detecting means) ) 176 stepping motor control circuit (drive control means) P recording material 201 photosensitive drum (image carrier) 206 transfer drum (recording material holding means) 206a transfer charger (transfer means) 207 recording sheet (recording material) 215 fixing device 227 Fixing roller (roller pair) 228 Pressure roller (low La vs)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI technical display location G03G 21/00 111

Claims (12)

[Claims] 1. A fixing roller for fixing an unfixed toner image formed on a recording material through a predetermined process onto the recording material, a scooping roller arranged so as to be immersed in a release agent, and A coating roller which is arranged so as to contact the drawing roller and applies a release to the fixing roller, and a metering which is arranged so as to contact the coating roller and regulates the coating amount of the release agent on the coating roller. An image forming apparatus having a blade, wherein the metering blade is arranged so that the axial position of the coating roller with respect to the surface of the coating roller is variable. 2. The image forming apparatus according to claim 1, wherein the position movement of the metering blade in the coating roller axial direction is performed in conjunction with the rotational driving of the coating roller. 3. A recording material of each image carrier having a plurality of image carriers each carrying an unfixed developer image of a different color on its surface, and an endlessly movable surface facing each image carrier. A recording material conveying means for sequentially conveying the recording material to the facing portion, a transfer means for transferring the unfixed developer image onto the recording material at the facing portion, and a recording material on which the unfixed developer image of each color is transferred. An image forming apparatus having a fixing means for nipping and conveying to fix a developer image on the recording material, comprising a speed detecting means for detecting a recording material conveying speed of the fixing means, and a drive control means for the fixing means. The image forming apparatus is characterized in that the drive control means is set to correct the recording material conveying speed of the fixing means to an appropriate value based on the speed detected by the speed detecting means. 4. The image forming apparatus according to claim 3, wherein the speed detecting means is means for measuring a time taken for the recording material to pass through the fixing means. 5. A recording material is provided on each of the image bearing members, which has a plurality of image bearing members each bearing an unfixed developer image of a different color on its surface and an endlessly movable surface facing each image bearing member. A recording material conveying means for sequentially conveying the recording material to the facing portion, a transfer means for transferring the unfixed developer image onto the recording material at the facing portion, and a recording material on which the unfixed developer image of each color is transferred. In an image forming apparatus having a fixing means for sandwiching and conveying and fixing a developer image on the recording material, a first speed detecting means for detecting a recording material conveying speed of the recording material conveying means, and recording by the fixing means. A second speed detecting unit for detecting a material conveying speed and a drive control unit for the fixing unit are provided, and the drive control unit is based on the detection speeds by the first and second speed detecting units. The recording material conveying speed of the recording material conveying means An image forming apparatus characterized in that the speed is set to be equal to the speed. 6. The image forming apparatus according to claim 5, wherein the first speed detecting means is a means for measuring a time taken for the recording material to pass a predetermined position on the surface of the recording material conveying means. 7. The image forming apparatus according to claim 5, wherein the second speed detecting means is a means for measuring the time taken for the recording material to pass through the fixing means. 8. The first speed detecting means is a means for measuring a time taken for the recording material to pass a predetermined position on the surface of the recording material conveying means, and the second speed detecting means is a fixing means for the recording material. The image forming apparatus according to claim 5, wherein the drive control means corrects the recording material conveying speed of the fixing means so that the passing times become equal to each other. 9. An image bearing member carrying a transferred image on a surface thereof,
A recording material holding unit that is arranged to face the image carrier and holds the recording material, and a transfer unit that transfers the transfer image on the image carrier to the recording material on the recording material holding member are in pressure contact with each other. And a fixing device for fixing the transferred image on the recording material by sandwiching and conveying the recording material, the fixing device comprising: An image forming apparatus in which the positions of parts are attached so as to be movable. 10. The recording material holding means is arranged so as to come into pressure contact with the image bearing member, and in the fixing device, the position of the pressure contact portion of the roller pair is relative to the pressure contact portion between the recording material holding means and the image bearing member. The image forming apparatus according to claim 9, wherein the image forming apparatus is movably attached so as to be parallel to each other. 11. The fixing device is arranged such that the position of the pressure contact portion of the roller pair is within the conveyance surface of the recording material guided to the pressure contact portion.
The image forming apparatus according to claim 9, wherein the image forming apparatus is attached so as to be parallel to a front end portion of the recording material. 12. The fixing device is mounted so as to move the position of the pressure contact portion of the roller pair depending on the type and size of the recording material guided to the pressure contact portion and the transfer condition. The image forming apparatus according to item 1.