JPH069096A - Image forming device - Google Patents

Abstract

PURPOSE:To prevent the breakage of a belt member, in an image forming device having an endless belt member, by preventing the distortion of the image forming device body and the deviation from the deflection control of the belt due to the change with the lapse of hours. CONSTITUTION:The position of a belt 101 is detected by a belt position detecting means 131, and when the deflection of the belt 101 is caused, a corrective roller 106 for retaining the belt 101 is alternately moved by an actuator 110 so as to describe an arc A-A', so that the belt 101 can be moved in a zigzag. The velocity of this zigzag movement is detected on the basis of the signal from a CCD 114 being a belt deflection velocity detecting means, and when the velocity of the zigzag movement of the belt 101 has deviated from a desired range, the amount of movement of the actuator 110 is corrected by a driver.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an image forming apparatus, and an image forming apparatus in which one or both of an image carrying means and a transfer material conveying means are composed of a belt holding mechanism and an endless belt member. In the image forming apparatus, the endless belt member is forcibly applied with a biasing force so that the endless belt member can be reliably driven within a constant movement range.

Further, the present invention has a plurality of image stations, and a color copying machine such as an electrophotographic system or an ink jet system for sequentially transferring a transfer material to each image station by a belt body conveying means to obtain multiple images, The present invention relates to an image forming apparatus such as a color printer.

Further, the present invention is a color image forming apparatus having a heat fixing device and a plurality of image forming means, and more particularly, a transfer material having an unfixed toner image is passed between a fixing roller and a pressure roller which are pressed against each other. The present invention relates to an image forming apparatus having a heat fixing device for fixing the unfixed toner image.

[0004]

2. Description of the Related Art As is well known, various types of image forming apparatuses have been developed which employ an electrophotographic system or an electrostatic recording system in the image forming process. In these various types of image forming apparatuses, a photosensitive drum is used as an image carrying unit, and a charging device, an exposing unit, peripheral devices such as a developing device, and a transfer material conveying mechanism are provided around the photosensitive drum. There is a format. Further, in recent years, in order to further improve the functions of the photosensitive drum and the transfer material transport mechanism, an endless belt member carrying a photoconductor is used instead of the photosensitive drum, and the transfer material transport mechanism also has an endless belt member. An image forming apparatus employing a belt-shaped belt member has been developed. As described above, in the image forming apparatus that uses the endless belt member for the transfer material transport mechanism including the photoconductor, it is possible to improve many functions, but it is unique to the belt mechanism. However, some means for suppressing the deviation of the belt and the occurrence of the snake movement during driving, which is a drawback of the above method, is indispensable. That is, the disadvantages such as deviation and meandering at the time of driving the belt are caused by the mechanical precision of the belt itself, the change in the characteristics of the belt, the transfer material from the transfer material supply mechanism, and the transfer material entering the transfer material transport belt. Since it is generated by various external forces such as the generated vibration of the conveyor belt, it is impossible to suppress the belt deviation or meandering without providing some means. Met.

Conventionally, the following methods have been adopted as means for correcting these problems when the belt is displaced or meandered. (A) A method in which the diameter of the roller member that holds the endless belt member is made larger at the central portion than at both end portions, and the roller member is formed so as to have a crown shape as a whole. (B) A method in which a guide groove is provided in each roller member, and a guide rib is provided in a portion corresponding to the groove on the inner peripheral side of the endless belt member. (C) A method of writing a registration mark on the belt member and optically correcting the relative displacement of the mark by feedback. (D) A method in which a registration mark is written on the belt member and the relative position of the belt holding member is varied based on the relative displacement of the mark. (E) A method of forcibly applying a biasing force to the belt member to intentionally cause the biasing and adjusting the image forming timing according to the amount of the belt shifting.

Conventionally, various types of color image forming apparatuses have been proposed which are equipped with the above-mentioned belt transfer material conveying means. One of them is an image forming apparatus for each color developer. A station is provided, and in each image station, a visible image for each color is formed on the photosensitive drum by a well-known image forming process, these visible images are sequentially transferred to a transfer material supplied from the outside, and are collectively fixed to form a color image. There is an electrophotographic color image forming apparatus for obtaining the above. In this case, the transfer material is placed on a conveyor belt, which is a thin belt member stretched between a driving roller located downstream in the conveying direction from the viewpoint of conveyance and other driven rollers, and sequentially conveyed to each image station. Then, the visible images formed on the respective photosensitive drums are sequentially transferred to this transfer material.

As described above, in the image forming apparatus in which a plurality of image stations are juxtaposed, the images are sequentially transferred onto the same surface of the same transfer material. Difference, that is, there is a problem that color shift occurs and the image quality deteriorates.
Conventionally, proposals have been made to improve color misregistration. However, there are various causes for this color shift, and all of them have not been solved yet.

As one form of color misregistration, color misregistration as shown in FIG. 13 occurs. In FIG. 13, the arrow Z direction is the transporting direction of the transfer material 206, and a uniform deviation occurs from the leading edge of the image in the arrow Z direction over the entire surface (hereinafter, referred to as top margin deviation). The cause is as follows. Accuracy of peripheral surface length of photosensitive drum from exposure position to transfer position of each station (mismatch) Accuracy of interval between stations (mismatch) Mismatch of angular velocity of rotation of each photoconductor Accuracy of moving speed of conveyor belt In order to improve the accuracy of the above, it has been proposed to drive all the photosensitive drums by the same drive source. Furthermore, the exposure timing can be changed for each device by using a digital type exposure means (for example, a laser beam). Therefore, it is also possible to eliminate the top margin shift by adjusting.

Next, similarly to the above-mentioned conventional example, an image carrier on which a well-known image forming process from latent image formation to toner image formation of visible image formation is performed, an endless conveyor belt and a plurality of belt holders. An image forming apparatus comprising: a transfer material transporting unit configured to include a roller, which supports a transfer material that transfers a toner image formed on an image carrier, and transports the transfer material to an image transfer unit facing the image carrier. An image forming apparatus that controls the image carrier to a constant temperature will be described.

The reason why the image carrier is controlled to a constant temperature in this image forming apparatus is to avoid problems due to temperature changes in the toner image forming and transferring steps. A control mechanism for performing this temperature control normally turns on / off current to the heating element through a microcomputer built in the image forming apparatus in response to a detection signal of a temperature detection sensor installed near the image carrier.
The circuit of the temperature control mechanism is operated regardless of ON / OFF of the power switch in order to shorten the rise time of the image forming apparatus when the power switch is turned ON. .

Next, a 4-drum laser beam printer which is an example of a laser beam printer having a plurality of optical scanning means will be described with reference to FIG.

In the printer, four image forming stations are provided around an electrophotographic photosensitive member (hereinafter, referred to as a photosensitive drum) which is a latent image bearing member and which is an image forming unit including a developing device. The image on the photosensitive drum formed by each of the image forming stations is transferred to the transfer material on the conveying means that moves and passes adjacent to the photosensitive drum.

As shown in FIG. 40, magenta, cyan,
Photosensitive drums 1M, 1C, 1Y, and 1K are arranged in the image forming stations Pm, Pc, Py, and Pk that form images of yellow and black, respectively, and the photosensitive drums are rotatable in the arrow directions. Has become. Also,
Around the photosensitive drums 1M, 1C, 1Y and 1K, chargers 2M, 2C, 2Y and 2K and scanning optical devices 3M and 3 are provided.
C, 3Y, 3K and developing devices 4M, 4C, 4Y, 4
K, and cleaners 5M, 5C, 5Y, and 5K are sequentially arranged along the rotation direction of the photosensitive drums, and a transfer unit 406 is arranged below each photosensitive drum. The transfer unit 406 includes a transfer belt 406a, which is a transfer material conveying unit common to each image forming station, and transfer chargers 6M, 6C, 6Y and 6K.

In the printer as described above, the transfer material P supplied from the paper feed cassette 407 serving as the transfer material supply means.
Is supported on the transfer belt 406a and conveyed to each image forming station, and the toner images of the respective colors formed on the respective photosensitive drums are sequentially transferred. When this transfer step is completed, the transfer material P is separated from the transfer belt 406a and is transferred to a fixing device 408, which will be described later, by a transfer belt 409 which is transfer material guiding means, and a full-color image is formed on the transfer material P. To be done.

Next, the fixing device in the above-described full-color image forming apparatus will be described with reference to FIG. 2. Description of the Related Art Conventionally, in a device using a dry powder developer, a heat roller fixing device which holds a transfer material between a fixing roller and a pressure roller and heats and presses an unfixed toner image on the transfer is widely used. Has been. FIG. 41 shows a schematic configuration of such a conventional fixing device. In addition to a fixing roller 411 that is rotatably arranged and a pressure roller 412 that rotates while being in pressure contact with the fixing roller 411, a releasing mold is also provided. It is configured to have a release agent application device 413 and a cleaning device 414 which are agent supply application means.

The fixing roller 411 has a structure in which the surface of a metal cored bar is covered with silicone rubber and fluororubber to a predetermined thickness, and includes a heater 411a such as a halogen lamp as a heating means and rotates in the arrow direction. Freely supported.

A pressure roller 412 is disposed below the fixing roller 411 so as to come into pressure contact therewith, and is pivotally supported so as to be drivenly rotated by the fixing roller 411. The pressure roller 412 is formed by providing a silicone rubber on the surface of a metal cored bar and applying a fluororesin coating on the surface thereof.
Like the fixing roller 411, a heater 412a such as a halogen lamp is provided as a heating means inside. Further, the thermistor 415 is arranged so as to abut on the pressure roller 412, and the heater 4 is connected via a temperature control circuit.
The surface temperature of the fixing roller 411 and the pressure roller 412 is adjusted by controlling the voltage to the heater 11a and the heater 412a.

The releasing agent coating device 413, which is disposed so as to come in contact with and separate from the fixing roller 411, has a releasing agent tank 413 which is a releasing agent container containing silicone oil as a releasing agent.
a, a scooping roller 413b that scoops the release agent from the release agent tank 413a, an application roller 413c that is a rotating body for application that applies the release agent to the fixing roller 411, and to control the application amount of the release agent. Blade 413 which is a regulating member of
and d. The rotatably supported application roller 413c has a sponge rubber surface coated with silicone rubber, and is detachably disposed on the fixing roller 411 to apply a release agent. The blade 413d is fixed to the sheet metal so as to contact the coating roller 413c at a constant angle, and is pressed against the coating roller 413c with a constant pressure. Therefore, the amount of the release agent applied by the pumping roller 413b is equal to that of the blade 4
The transfer material P is adjusted to be constant by 13d and applied from the front end to the rear end of the transfer material P.

Further, a cleaning device 414 is in contact with the fixing roller 411 and the pressure roller 412, and a nickel web 414a is provided on the fixing roller 411 side.
Nomex felt 414b on the pressure roller 412 side
Is pressing and cleaning the rollers.

When the transfer material P is conveyed to the fixing device as described above, the fixing roller 411 and the pressure roller 412 rotate at a constant speed, and the transfer material P moves between the fixing roller 411 and the pressure roller 412. When passing, the unfixed toner T carried on the surface by being pressed and heated at a substantially constant pressure and temperature from both the front and back sides was melted and good fixing was performed.

[0021]

However, each of the above conventional examples has the following problems.

First, the conventional methods for correcting the deviation of the belt shown in (a) to (e) above have the following problems. That is, the above-mentioned method (a) is the most widely used correction means, but the roller member is formed into a crown shape to distort the endless belt member and generate an internal stress difference, thereby making It is necessary to use a belt made of a material having sufficient elasticity in order to suppress the deviation of the belt. Moreover, since the so-called permanent deformation of the belt member due to creep strain is prevented while utilizing the strain generated in the belt member, when using a rubber belt, for example, use a material with low rubber hardness and high elasticity. It is necessary to adopt it, and it is necessary to set the thickness so as to satisfy the mechanical strength. Therefore, when the method (a) is applied to a photosensitive belt or the like, the surface of the belt is distorted, so that the image is deformed, which is not suitable. Since the thickness of the belt must be increased, the transfer current must be set high, which is also not suitable.

Next, in the method (b), since the thrust force generated in the belt member is received by the guide rib end surface, the deviation of the belt member is suppressed. The accuracy of the ribs determines the accuracy of the moving speed control of the belt member. However, it is technically very difficult to attach the guide rib to the inner peripheral side of the belt member with high precision, and therefore the moving speed of the belt member cannot be controlled with high precision, and it is suitable for mass production. Absent.

In the above method (c), since it takes time to perform feedback for adjusting the optical system, it is difficult to give feedback every time an image is formed, and the belt is permanently attached. This problem cannot be solved by this method, which causes deviation of the belt and breakage of the belt.

Next, the above-mentioned method (d) is intended to cause the belt to move substantially straight in the vicinity of the target position, as shown by the chain double-dashed line curve in FIG. There is a problem in that the responsiveness of the belt deviation to the change of the belt and the delicate change of the relative position of the belt do not follow the deviation direction and the deviation degree.

Next, the above method (e) is the same as the above (a) to (a).
It has many advantages over the method (d), and is more realistic in terms of belt deviation control. However,
The above (e) also has the following problems.

First, depending on the environment in which the device is placed,
The device body is twisted. Since this twisting also involves twisting of the belt supporting portion, the belt deviates from the deviation control amount set at the time of assembling the apparatus, and the belt deviates only in one direction, and eventually the belt is broken.

Secondly, due to changes over time, such as the plastic deformation of the belt caused by the durability, the deviation of the belt is changed, and the deviation deviates from the deviation control amount set at the time of assembly as described above, resulting in breakage. It has a problem of deviation of control.

Further, in the conventional example in which the top margin shift as shown in FIG. 13 occurs, there are the following problems. This is a problem of temperature, and in addition to the causes described above, a top margin shift may occur due to a temperature rise in the device and a change in environmental temperature around the device installation.

A rubber roller is usually used as the drive roller for the above-mentioned conveyor belt because the conveyor belt is driven by a frictional force, so that the friction coefficient is large and the conveyor belt is not damaged. However, the coefficient of linear expansion of rubber is much larger than the coefficient of linear expansion of the metal material constituting the device (about 20 times that of iron).

Therefore, when the temperature inside the apparatus rises or the environmental temperature changes, the diameter of the driving roller changes largely as compared with the other elements, and therefore the conveying speed of the recording material changes. As a result, the time required for the transfer material to reach each image station varies depending on the temperature, and as a result, color misregistration occurs. Obviously, the above phenomenon can be solved by using the same material as the metal material for the supporting portion of the photosensitive drum, such as iron, as the material of the driving roller, but if the surface is not sandblasted, sufficient friction force can be obtained. However, there is a problem in that it causes a small scratch on the back side of the belt.

Further, in the above-mentioned conventional apparatus for controlling the temperature of the image carrier, the image carrier and the transport belt of the transfer material transport means are in contact with each other when the apparatus is stopped. Further, the image carrier is usually a cylindrical member, and the temperature is controlled by the heating element to maintain the temperature at the set temperature even when the apparatus is stopped. Since the transport belt is often made of a resin material having low elasticity so that the influence of distortion of the transport belt on the image forming apparatus is reduced, the transport belt contacting the image carrier when the measures are stopped is If it is subjected to a thermal effect for a long time through the contact portion with the circumferential portion of the carrier, permanent deformation easily occurs.

The transfer belt is designed to support the transfer material in a state of being completely adhered thereto by electrostatic attraction and to transfer the transfer material to the image transfer portion. Therefore, the deformation of the transfer belt causes incomplete contact of the transfer material. As a result, the transfer material floats from the transport belt. In such a situation, the floating of the transfer material disturbs the transfer current generated between the image carrier and the transfer material, and the image quality of the image on the transfer material obtained by the transfer is significantly deteriorated, or the conveyor belt is used. In some cases, the corrugation of the transfer material causes the transfer material to jam at the contact portion between the image carrier and the conveyor belt.

Further, even if the transfer material is not jammed or the like is serious, if the conveyor belt is deformed, unevenness in speed may occur when the conveyor belt is driven. In a full-color image forming apparatus that causes deterioration, it becomes a serious problem.

Further, in the fixing device in the above-mentioned conventional 4-drum laser printer, the amount of heat required for fixing is higher than usual as in the case of fixing a transfer material having a large weight per unit area (hereinafter referred to as basis weight). In many cases, the following problems occurred.

In the color image forming apparatus, the toner layer becomes thicker than that of the black and white image forming apparatus due to the multiple transfer of magenta, cyan, yellow and black. Therefore, as described above, both the fixing roller 411 and the pressure roller 412 are used. The heaters 411a and 412a heat the transfer material P from both front and back surfaces, and the temperature inside the rollers and the image forming apparatus is relatively high. However, in general, when fixing a transfer material with a large basis weight, it is necessary to supply a larger amount of heat than plain paper, so the surface temperature of the roller must be set higher, and the life of the roller and the image It had a bad influence on the temperature rise in the forming apparatus.

Therefore, a method has been proposed in which the fixing speed is slowed down and the heat supply time is lengthened. However, when such a method is used, a difference occurs between the image forming speed and the fixing speed in the image station. The transfer material P is the fixing roller 411.
There is a problem that the transfer material P loops due to a speed difference and disturbs an image when it is rushed into the pressure contact portion of the pressure roller 412. Therefore, the transfer material P is transferred to the transfer portion 40.
A method has been proposed in which the speeds of the fixing roller 411, the pressure roller 412, and the conveyor belt 409 are delayed at the time when the sheet passes through all 6 and is placed on the conveyor belt 9. However, in the case of such a method, at least the transfer unit 406 and the fixing device 408 are used.
Therefore, the color image forming apparatus needs to be provided with a plurality of image forming stations as described above, and the entire apparatus becomes large. Therefore, in order to use this method without increasing the size of the apparatus, it is necessary to shorten the distance between the transfer unit 6 and the fixing device 8, and the transfer material size is limited when fixing a transfer material having a large basis weight. There was a problem.

Further, conventionally, since the blade 413d is pressed against the coating roller 413c at a constant angle and pressure, the amount of release agent applied is always kept constant regardless of the type of transfer material or the type of image. In some cases, the release agent was applied in an amount more than necessary. That is, when fixing a transfer material having a large grammage, the fixing property becomes worse than that of a transfer material having a small grammage, and thus a larger amount of the release agent is required. Therefore, the coating amount of the release agent is set to the coating amount necessary for fixing the transfer material having a large basis weight. Therefore, even when a transfer material having a small basis weight is fixed, the release agent is applied at an optimum application amount when fixing a transfer material having a large basis weight, so that the release agent is more than necessary amount. It deteriorated the image quality and accelerated the release agent consumption.

The first object of the present invention is to prevent the deviation of the belt deviation control from the deviation of the belt member due to the twisting of the main body of the image forming apparatus or the change over time in the image forming apparatus having the endless belt member, and the damage of the belt member. An object of the present invention is to provide an image forming apparatus capable of preventing the above.

A second object of the present invention is to provide an image forming apparatus having a plurality of image stations on a belt conveying means to obtain a multiple image, in which temperature rise and environmental temperature in the image forming apparatus are increased. An object of the present invention is to provide an image forming apparatus that does not cause a top margin shift even when a change occurs.

A third object of the present invention is to prevent the transfer belt of the transfer material transfer means for transferring the transfer material to the image transfer portion facing the image carrier from being deformed by heat from the image carrier when the apparatus is stopped. By preventing the transfer, the toner image formed on the image carrier on the transfer material carried on the conveyor belt can be transferred without image quality deterioration due to floating of the transfer material due to deformation of the conveyor belt, resulting in good quality. It is to provide an image by making it possible to easily obtain the image.

A fourth object of the present invention is to increase the temperature inside the apparatus and the apparatus even when the amount of heat required for fixing is large in a color image forming apparatus such as when a transfer material having a large basis weight is used. It is an object of the present invention to provide an image forming apparatus that does not cause an increase in size, defective coating of a release agent, and the like.

[0043]

According to the first invention of the present application,
The first object is to provide at least one image carrier that performs an image forming process from latent image formation to visible image formation, or a transfer material that conveys a transfer material onto which a visible image is transferred on the image carrier. At least one of the conveying means is an image forming apparatus having an endless belt member and a belt holding mechanism having a plurality of rotatable supports that hold the endless belt member, And a belt position detection means for detecting the position of the endless belt member in the direction transverse to the moving direction of the endless belt member and the deviation direction thereof. , The moving means alternately moves the rotatable support body to a first position and a second position in accordance with the output of the belt position detecting means, thereby operating the endless belt member at a constant speed. In an image forming apparatus set to forcibly reciprocate within a surrounding area, belt deviation speed detecting means for detecting reciprocating speed of the endless belt member, and correction of movement amount of the rotatable support member. It is achieved by having a moving amount correcting means for adjusting the moving amount of the rotatable support according to the output of the belt deviation speed detecting means. .

According to the second invention of the present application, the second object is to provide a plurality of image stations on which a visible image is formed and adjacent to the image stations, carry a transfer material, and circulate. A transfer material transporting means, two or more rollers that stretch and hold the transfer material transporting means, and a driving means that drives at least one of the rollers to circulate the transfer material transporting means. In the image forming apparatus described above, the temperature control means detects the temperature of the roller driven by the drive means, and the speed control means that adjusts the rotation speed of the roller.
This is achieved by setting the rotation speed of the roller in accordance with the output of the temperature detecting means.

Further, according to the third invention of the present application, the second object is to provide a plurality of image stations on which a visible image is formed, and adjacent to the image stations, and carry a transfer material in a circular movement. A transfer material transporting means, two or more rollers that stretch and hold the transfer material transporting means, and a driving means that drives at least one of the rollers to circulate the transfer material transporting means. In the image forming apparatus, the image forming apparatus has a temperature detecting means for detecting the temperature of the roller driven by the driving means, and a temperature adjusting means for adjusting the temperature of the roller. This is achieved by setting the temperature of the roller as a function of output.

According to the fourth aspect of the present invention, the third object is to provide at least one temperature-controlled image carrying means for carrying out an image forming process from latent image formation to visible image formation, and the above image carrying means. A transfer material transporting means for transporting a transfer material for transferring a visible image formed on the image carrying means, which is composed of an endless transport belt in contact with the means and a plurality of rotatable belt holding mechanisms. In the image forming apparatus, it is achieved by disposing the conveyor belt so that it can be brought into contact with and separated from the image carrying means, and when the conveyor belt is stopped, the contact of the conveyor belt with the image carrying means is released to bring the conveyor belt into a non-contact state. To be done.

And. According to the fifth invention of the present application, the fourth object is to provide a transfer material supplying means for accommodating the transfer material and supplying the transfer material at any time, and a transfer material conveying means for conveying the transfer material supplied from the transfer material supplying means. A plurality of image forming means arranged in parallel along the transporting direction of the transfer material so as to face the transfer material transporting means and carrying unfixed developer images of different colors on the transfer material; It is rotatably arranged in front of the material conveying means in the conveying direction of the transfer material so as to have a heating means inside so as to be in pressure contact with each other, and to heat and press the unfixed developer image on the transfer material. In an image forming apparatus having fixing means for fixing, an auxiliary heating means for supplying a predetermined amount of heat to the transfer material and the unfixed developer image on the transfer material is provided between at least one adjacent image forming means. By doing It is made.

According to the sixth invention of the present application, the fourth object is to transfer the transfer material, which stores the transfer material and supplies the transfer material at any time, and to convey the transfer material supplied from the transfer material supply means. A plurality of image forming means for carrying the transfer material conveying means and a plurality of image forming means for carrying the unfixed developer images of different colors on the transfer material, which are arranged in parallel along the conveying direction of the transfer material so as to face the transfer material conveying means. And a heating means inside thereof, which is rotatably disposed in front of the transfer material conveying means in the conveying direction of the transfer material and in pressure contact with each other, and heats and pressurizes the unfixed developer image. In the image forming apparatus, the image forming apparatus comprises: a fixing unit for fixing the transfer material on the transfer material; and a transfer material guiding unit arranged between the fixing unit and the transfer material conveying unit for guiding the transfer material to the fixing unit. The means is vertical Alternatively, the transfer material guiding means is arranged so as to be movable in the carrying direction, and the transfer material guiding means is variably arranged so as to have a length in the carrying direction corresponding to the moving amount of the fixing means. Is also achieved.

Further, according to the seventh invention of the present application, the fourth object is to have an image forming means for forming a multicolor or monochromatic unfixed developer image and carrying it on a transfer material, and a heating means inside. Fixing means for rotatably arranging while pressing each other and fixing the image on the transfer material by heating and pressurizing the unfixed developer image, and a releasing agent for supplying and applying a releasing agent to the fixing means. A release agent supply and coating means, the release agent supply and coating means is disposed so as to abut the fixing agent, and the release agent in the release agent storing container. In the image forming apparatus, there is provided an image forming apparatus having a coating rotator for supplying and coating a fixing agent to the fixing means, and a regulating member arranged so as to be in contact with the coating rotator and regulating a supply coating amount of the release agent. The regulation member of the mold agent application and supply means is
A plate-shaped drive unit is provided so as to change the contact angle with respect to the coating rotary member, and a drive unit that variably drives the contact angle of the regulating member, and controls the drive by the drive unit. It is also achieved by having a control means.

[0050]

According to the first aspect of the present invention, the position of the endless belt member during the image forming operation is detected by the belt position detecting means. For example, when the belt is deviated, the belt holding mechanism is rotatable. Since such a support is moved to the first position and the second position alternately by the moving means, the belt reciprocates within a certain movable range, and the deviation and the meandering are prevented. Further, the present invention is
The reciprocating speed of the belt is detected by the belt deviation speed detecting means, and it is detected that the range of the moving amount of the belt deviates from a desired range. At this time, since the movement amount of the rotatable support is corrected by the movement amount correcting means, even if the image forming apparatus body is twisted or the belt or the like is changed with time, the belt piece Surely prevent leaning and meandering.

Further, according to the second aspect of the present invention, the temperature of the driving roller that circulates the transfer material conveying means is detected by the temperature detecting means, and the change in the temperature is transmitted to the speed controlling means of the driving roller. Has been done. Then, for example, when the temperature inside the image forming apparatus rises above a predetermined temperature, the rotation speed of the drive roller is reduced by the speed control means to prevent the occurrence of "color shift".

Further, according to the third invention of the present application, the temperature of the drive roller is detected by the temperature control means as in the second invention, but in the third invention, the change of the temperature is transmitted to the temperature adjusting means. To be done. Then, the temperature adjusting means maintains the temperature of the drive roller at a predetermined temperature and does not change the roller diameter.

According to the fourth aspect of the present invention, the transfer belt can be moved up and down so that the transfer belt can be brought into contact with and separated from the image carrier, or at least one belt of the transfer material transfer means. By making the holding mechanism swingable, the conveyor belt can be brought into contact with and separated from the image carrier, and the tension of the conveyor belt can be changed. Therefore, without releasing the contact of the transport belt with the image carrier for a time period in which thermal deformation due to the contact of the transport belt with the image carrier can be prevented, the transport belt and the Keep the image carrier non-contact.

According to the fifth aspect of the present invention, the auxiliary heating means for supplying a predetermined amount of heat to the transfer material and the unfixed developer image on the transfer material is disposed between at least one adjacent image forming means. For example, when the weight of the transfer material per unit area is large and the amount of heat required for fixing in the fixing means is large, the auxiliary heating means is driven. Then, the transfer material passing between the image forming means receives a predetermined amount of heat from the auxiliary heating means before the original fixing, and the unfixed developer image on the transfer material is easily melted. Then, after the image formation in all the image forming means is completed, when the fixing means is heated at a normal temperature, the unfixed developer image is surely melted and fixed. In this way, even when the amount of heat required for fixing is large, good fixing can be performed without raising the temperature in the fixing unit more than necessary.

Further, according to the sixth aspect of the present invention, the fixing means is arranged so as to be movable in the vertical direction or in the transfer material conveying direction, and the transfer material guiding means corresponds to the moving amount of the fixing means. Since the length in the carrying direction is variably arranged, for example, when the weight per unit area of the transfer material is large and the heat amount required for fixing in the fixing means is large, the fixing means is moved downward or forward in the carrying direction. Then, the transfer material guide means is extended accordingly. Then, when the image formation is completed and the rear end of the transfer material has come out of the image forming means, the front end of the transfer material has not yet entered the fixing means.
Therefore, at this time, if the fixing speed of the fixing means is reduced, the transfer material is guided to the fixing means without giving an impact to the transfer material due to the speed difference between the image forming speed and the fixing speed. The transfer material rushed into the fixing means is heated while being conveyed at a slower speed than usual, so that a sufficient amount of heat is received even at a normal fixing temperature to perform good fixing. On the other hand, in the case of plain paper having a small weight per unit area, the fixing means is moved to the original position and the transfer material guiding means is shortened to the original minimum length. Then, in this case, the fixing is performed at a normal speed. Therefore, if the moving area of the fixing unit is secured, good fixing can be performed without increasing the size of the entire apparatus.

Further, according to the seventh invention of the present application, since the regulating member of the releasing agent supplying / coating means is formed in a plate shape and the contact angle with respect to the coating rotator is variable, for example, per unit area of the transfer material. Is large and the amount of heat required for fixing in the fixing means is large, the contact angle of the regulating member is increased. As a result, the amount of the release agent supplied to the fixing unit increases, and even when the amount of heat required for fixing is large and the fixing property tends to deteriorate, the adhesion of the developer to the fixing unit is suppressed and good fixing is performed. On the other hand, in the case of plain paper, the contact angle of the regulating member is reduced. Then, the amount of the release agent supplied to the fixing unit is suppressed, and wasteful consumption of the release agent is prevented.

[0057]

Embodiments 1 to 16 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. In the image forming apparatus according to the present invention, at least one of the image carrying means and the transfer material carrying means included in the apparatus has a belt holding mechanism and an endless belt member. An image forming process from latent image formation to visible image formation is executed in the means, and the transfer material conveying means conveys a transfer material onto which the visible image on the image carrying means is transferred. is there. Since the functions of the above-mentioned means are already well known, detailed description thereof will be omitted.

FIG. 1 is a schematic perspective view showing a first embodiment of an image forming apparatus according to the present invention. In the image forming apparatus of this embodiment, only the transfer material conveying means has a belt holding mechanism and an endless belt member. Although it has a structure, it goes without saying that only the image carrying means may have the same structure or both means may have the same structure. Further, since the color image forming apparatus is provided with the image carrying means at four places, it is not limited to this, and the present invention can be applied to an image forming apparatus having an arbitrary number of image carrying means. is there.

Since the image forming apparatus of FIG. 1 adopts the electrophotographic image forming apparatus process, the rotary polygon mirror 1 is provided on the four uniformly charged photosensitive drums 161 to 164.
A latent image of an image to be copied is formed through the mirror 30 and the reflecting mirrors 141 to 152, converted into a visible image by a developing device (not shown), and an endless belt member (hereinafter simply referred to as a belt) of a transfer material conveying unit. ) 101, it is configured to be transferred onto a transfer material (not shown). The belt 101 includes a driving roller 104, a tension roller 105, and a correction roller 10 that form a belt holding mechanism.
6 and the driven roller 107, and moves in the direction of the arrow Z shown.

Next, the image forming apparatus according to the present invention shown in FIG. 1 will be described in detail with reference to FIG. 2 showing the detailed structure of the belt and the belt holding mechanism which are the gist of the present invention.

Each of the rollers constituting the belt holding mechanism is rotatably supported, and the driving roller 104 and the driven roller 107 are arranged in a corresponding relationship.
Moreover, both are fixed at predetermined positions. A drive motor 108 that drives the drive roller 104 to rotate in the direction of arrow B in the drawing is connected to the rotary shaft of the drive roller 104. The correction roller 106 corrects defects such as deviation and meandering that occur on the belt 101. One end side of the rotation shaft of the correction roller 106 is a pivot bearing 112, and the other end side is a bearing 109. It is supported. The bearing 109 is connected to a rod 111 which is coaxially connected to the operating shaft of an actuator 110 which is a variable adjusting means.
As the operating shaft of 10 reciprocates along the belt 101, as shown by X in FIG.
As indicated by A ', the movement is performed by drawing a slight arc. That is, since the correction roller 106 has the pivot bearing 112 fixed, the other end side (that is, the bearing 109 side) of the pivot roller bearing 112 is actuated by the operation of the actuator 110 as shown by an arrow A-A in FIG. As indicated by ', the bearing 110 is moved in an arcuate direction (direction along the belt 101) in an arcuate manner, whereby the center axis of rotation of the correction roller 106 moves in the direction along the belt 101.
An arbitrary angle can be taken with the original position of 6. In this embodiment, a linear stepping motor is used as the actuator 110, and the correction roller 1
The movement amount of the rotation center axis of 06 can be easily set by changing the number of pulses of the drive command signal (pulse signal) output to the linear stepping motor.

Further, a suitable mark 102 such as a registration mark is provided on the belt 101, and the mark 102 is provided on the belt along a direction transverse to the moving direction of the belt 101. It is detected by the belt position detecting means 131 which detects the sign. In this embodiment,
The belt position detecting means 131 includes an illuminating means 113 for illuminating the belt along a direction transverse to the moving direction of the belt 101, and a CCD (electric charge) for detecting the reflected light from the sign 102 and converting it into an electric signal. Coupling element) array 11
4 and.

In the above structure, the actuator 11
For example, when the rotation center axis of the correction roller 106 is moved from the original position C shown by the dotted line to the position C ′ shown by the solid line in the moving direction of the belt 101 as shown in FIG. However, unlike the case where the correction roller 106 is in the original position, a twist angle is generated between the correction roller 106 and other rollers, so that the winding position of the belt 101 is changed from the position shown by the broken line in FIG. The belt 101 moves to the position shown by the solid line (shown by the distance α), and the belt 101 is biased. On the contrary, when the rotation center axis of the correction roller 106 is moved from the original position C shown by the dotted line in the direction opposite to the moving direction of the belt 101 (this moving direction is the − direction), the correction roller 106 is also moved to the original position. Unlike the case described above, since a twist angle is generated between the roller 101 and another roller, the winding position of the belt 101 shifts from the position shown by the broken line in FIG. 3 to the outside (to the right side) in FIG. The belt 101 is biased in the opposite direction. Therefore, if the position of the belt 101 is always forcibly moved between the maximum offset position in the + direction and the maximum offset position in the − direction of the belt movement range,
That is, when one end of the belt 101 reaches the maximum offset position in the + direction, the correction roller is tilted to move the belt in the − direction, and when the opposite end of the belt 101 reaches the maximum offset position in the − direction. If the belt position is always forcibly moved in a zigzag manner at a predetermined deviating speed such as inclining the correction roller in the opposite direction to move the belt in the + direction, the belt 101 is always moved as shown by the solid line in FIG. It can be driven within a certain range, and accidents such as belt damage can be prevented.

For forced zigzag movement of the belt 101, for example, as shown in FIGS. 5 and 6, the maximum deviation position information in the + direction and the maximum deviation position information in the − direction of the belt movement range are stored in advance. The correction roller is stored in 121, and a predetermined amount of movement of the correction roller about the original position C is −, +.
Direction alternate. That is, when the correction roller 106 is moved S _{1 in the} + direction from the original position, the belt starts moving in the + direction. At this time, the belt position and moving direction are set to CCD.
Array 114 detects. As shown in FIG. 7, this CC
D denotes a large number of light receiving elements a to
k (actually, more light receiving elements are arranged)
As can be easily understood from FIGS. 7A and 7B, the elements a to k for receiving the light reflected from the mark 102 on the belt 101 according to the movement of the belt position are arranged. Since it changes, the belt position can be accurately detected by detecting which element produces the output,
It also serves as a belt deviation speed detecting means for detecting the belt moving direction and the deviation speed (deviation amount / time for one rotation of the belt) by comparing which element the output is generated every other rotation. . Further, the maximum offset position information such as the + direction is read from the memory 121 by the comparison operation circuit 120.
To the position information of the mark 102 on the belt 101 detected by the CCD 114, and the position of the correction roller 106 is kept at S ₁ until the comparison result becomes 0.

As shown in FIG. 6A, when one end of the belt reaches the maximum offset position in the + direction, the comparison operation circuit 1
Since the comparison result of 20 is 0, the driver 123 moves the correction roller 106 in the − direction from the current position by S ₁ + S ₂ , and at the same time, the maximum offset position information in the − direction is read from the memory 121 to the comparison calculation circuit 120. Be done. On the other hand, the belt starts to move in the + direction by turning in the moving direction, as shown in FIG.
As shown in FIG. 5, the comparison calculation result becomes 0, and the driver 123 moves the correction roller 6 in the + direction from the current position by S from the current position in the same manner as when the opposite end of the belt reaches the maximum offset position in the − direction.
₁ + S ₂ is moved, so that the above-described operation is repeated. Thus, as shown in FIG. 4, the belt 101 reciprocates in a zigzag manner between the maximum offset position in the + direction and the maximum offset position in the − direction within the movable range. Then, at this time, the correction roller 106 alternately moves from the original position to + S ₁ (first position) and −S ₂ (second position).

However, if the apparatus main body is twisted or the belt is plastically deformed due to durability, this relationship is broken, and the correction roller 6 is reciprocated even if it is alternately moved between + S ₁ and -S _2. It doesn't move, it only moves in the-direction. Then, at that time, it was confirmed that the deviation speed of the belt was changed as a sign that the zigzag reciprocation control was deviated.

In this embodiment, as shown in FIG. 8, the amount of movement of the correction roller 106 is corrected. When the belt deviation speed is detected and calculated by the belt deviation speed detecting means, as shown by R3 → R4 in FIG. 8, the belt deviation speed (the inclination of the straight line in FIG. 8) is the normal R1 → It is determined that the speed is significantly faster than the speed to R2. At this time,
The correction roller 106, which has been moving between + S ₁ and -S ₂ until now, is moved once in the + direction by S ₁ + S ₂ + ΔS ₁ . This ΔS ₁ is calculated from ΔS ₁ = K · Δv (K ... Coefficient obtained by experiment) with respect to the deviation amount Δv of the deviation speed, and is automatically set in the driver 123 from the deviation amount of the deviation speed. , Are added to the movement amount of the actuator 110.

By this correction, the belt also returns to the normal deviation speed, and this time, as if the original position of the correction roller 106 is apparently shifted by ΔS, + (S ₁ + ΔS ₁ )
And −S ₂ + ΔS ₁ the correction roller 106 repeats its movement. Then, by this correction, deviation of the deviation control is avoided.

Further, the shift of the visible image transferred from each image bearing means (photosensitive drum in this embodiment) to the transfer material (the conveying direction of the belt 101) caused by the forced zigzag movement of the belt position as described above. The positional deviation of each color in the direction substantially perpendicular to the above) is obtained by calculating the deviation speed of the belt 101 based on the deviation amount of the belt 101 read by the CCD 114 and the time required for the belt 101 to make one round, and based on the result, This can be corrected by adjusting the image timing with respect to the image carrying means.

However, since the positional deviation between the photosensitive drums is significantly smaller than the amount of deviation of the belt, the correction may be ignored.

<Second Embodiment> Next, a second embodiment of the present invention will be described with reference to FIGS. 9 and 10. The same parts as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In the above-mentioned embodiment 101, the CCD array and the marker 102 are used as the belt position detecting means and the belt deviation speed detecting means. However, as shown in FIG. 9 and FIG. End face sensors 131a and 131b (normally used groove type photo interrupter or a mechanical sensor by a combination of a lever and a groove type photo interrupter are suitable) are arranged, and end face sensors 131a and 131b are arranged.
By determining which of the two detects the belt end surface,
The belt deviation direction and its position are detected. Further, the belt reciprocates in zigzag, and the end face sensors 131a, 13a
Since 1b alternately detects, the detection time interval T is measured by a timer. The end surface sensors 131a and 131b are
Since the position is fixed, the belt deviation speed is calculated by the following equation using α ₁ and α ₂ in FIG.

Belt deviation speed = (α ₁ + α ₂ ) / T Since the other construction and the correction method are the same as those in the above-mentioned embodiment, the description thereof will be omitted.

With such a configuration, in the above-described embodiment, the belt deviation direction and the deviation speed are not discriminated until the belt makes one round and the marker reaches the CCD, but since the belt end surface is continuous, the maximum. There is an advantage that a delay does not occur in responsiveness near the one-sided position and an advantage that it can be easily configured as compared with the CCD.

In the above embodiment, the case where the present invention is applied to the electrophotographic image forming apparatus has been described, but the present invention can also be applied to the electrostatic recording type image forming apparatus. Further, in the image forming apparatus of the above embodiment, only the transfer material conveying means has the belt holding mechanism and the endless belt member. However, even if only the image carrying means has the same constitution, Both the carrying means and the transfer material carrying means may have a belt holding mechanism and an endless belt member. Further, the present invention is not limited to the color image forming apparatus. Further, it goes without saying that the disposition position of the correction roller, the moving means of the rotation center axis of the correction roller, the moving direction, etc. can be variously changed as necessary.

<Third Embodiment> Next, a third embodiment of the present invention will be described with reference to FIGS. FIG. 11 is a schematic sectional view of an apparatus in which the present invention is applied to an electrophotographic color printer. In this embodiment, four image stations P, namely, first, second, third and fourth image stations P are provided in the printer body 210.
Although a, Pb, Pc and Pd are provided, the present invention is not limited to this, and the present invention can be applied to an image forming apparatus including an arbitrary number of one or more image stations.

A paper feed mechanism 213 is provided on one right side of the main body 210 shown in FIG. 11, and a transfer material discharge port 214 is provided on the opposite side, that is, the left side of FIG. In addition, the stationary device 2 is provided inside the discharge port 214.
07 are provided. Further, below the path from the paper feeding mechanism 213 to the fixing device 207 in the main body 210, there is a driven roller means, that is, an idler roller 212, in proximity to the paper feeding mechanism 213, and the fixing device 2
In the vicinity of 07, drive side roller means, that is, drive roller 21
1 are provided respectively, and these rollers 211 and 211 are provided.
A conveyor belt 208 is stretched between the twelve. In addition, below the drive roller 211, the conveyor belt 208 is provided.
An adjusting roller 276 is provided which comes into contact with the conveyor belt 208 from the inner peripheral side thereof and freely adjusts the pulling force of the conveyor belt 208. On the other hand, on the upper side of the path from the idler roller 212 to the drive roller 211, the first, second, third and fourth image stations Pa are arranged in order from the side of the paper feeding mechanism 213 in the vicinity of the conveyor belt 208. , P
b, Pc and Pd are arranged in parallel.

The conveyor belt 208 is frictionally driven in the direction indicated by arrow Z in FIG. 11 by the driving roller 211, carries the transfer material 206 fed through the paper feeding mechanism 213, and carries the above-mentioned image forming stations Pa. , Pb, P
It is sequentially conveyed to c and Pd.

The paper feed mechanism 213 includes a paper feed cassette 251 which is detachable from the main body 210, a rotatable paper feed roller 252 and a paper feed roller 252 which are provided at a mounting portion of the main body 210 to which the paper feed cassette 251 is attached. By body 2
A paper feed guide 253 for guiding the transfer material 206 fed into the sheet 10 and a pair of registration rollers 28 for receiving the transfer material 206 guided by the paper feed guide 253 and sending it to the idler roller 212 side at a predetermined timing.
0, a sensor (not shown) that outputs a predetermined signal when the tip of the transfer material 206 moving in the paper feed guide 253 is detected, and the like. This paper feed mechanism 213 is
The transfer material 206 is placed on the conveyor belt 208 from the idler roller 212 side.

The fixing device 207 receives the transfer material 206 fed from the drive roller 211 side, and receives the transfer material 206 from each image station P.
The visible images transferred on the transfer material 206 at a, Pb, Pc, and Pd are collectively fixed to form a permanent image. Then, the transfer material 206 carrying the permanent image
Is discharged onto the discharge tray 271 that is detachably attached to the copying machine main body 210 at the transfer material discharge port 214.

The image stations Pa, Pb, Pc and Pd have substantially the same structure, and the arrow F shown in FIG.
Photosensitive drums 201a, 201b, which are rotationally driven in the direction
Chargers 215a, 21 for uniformly charging the photosensitive drums, including 201c and 201d, are provided around the photosensitive drums.
5b, 215c and 215d, developing devices 203a, 203b, 2 for developing the electrostatic latent image formed on the photosensitive drum
03c and 203d, transfer material 206 to the developed visible image
Transfer material discharger 204a, 204b, 204
c and 204d, and cleaning means 205a, 205b, 205c and 205d for removing the toner remaining on the photosensitive drum are sequentially arranged in the drum rotating direction. Further, each of the photosensitive drums 201a, 201b, 201c and 2
The imaging lenses 217a, 217b, 21 are provided above 01d.
7c and 217d and laser beam scanner 216
a, 216b, 216c and 216d are provided respectively.

The developing device 203a contains magenta toner, and the developing device 203b contains cyan toner.
The developing device 203c stores yellow toner, and the developing device 203d stores black toner.
The laser beam scanners 216a, 216b, 216
c and 216d are a semiconductor laser, a polygon mirror, and f
A laser beam, which is composed of a θ lens or the like, receives an input of an electric digital pixel signal, and modulates a laser beam corresponding to this signal through the imaging lenses 217a, 217b, 217c and 217d, respectively, and the chargers 215a, 215b, 2
15c and 215d and developing devices 203a, 203b, 2
Between 03c and 203d, the drum surface is exposed by scanning in the drum generatrix direction. The laser beam scanner 216a receives a pixel signal corresponding to a magenta component image of a color image, the laser beam scanner 216b receives a pixel signal of a cyan component image, and the laser beam scanner 216c receives a pixel signal of a yellow component image. , And the pixel signals corresponding to the black component image are input to the laser beam scanner 216d. Further, an adsorption charger (not shown) is provided between the first image forming station Pa and the sheet feeding mechanism 213, and the adsorption charger is a transfer material supplied from the sheet feeding mechanism 213. 20
Corona discharge is performed in order to ensure that 6 is attracted to the conveyor belt 208. On the other hand, between the fourth image station Pd and the fixing device 207, a static eliminator (not shown) is provided almost directly above the drive roller 211, and the static eliminator is attracted to the conveyor belt 208. An alternating current is applied to separate the transfer material 206 present.

In the color printer having the above structure, as shown in FIG.
As shown in FIG. 5, a cut sheet-shaped material is used as the transfer material 206, and when the transfer material 206 is sent out from the paper feed cassette 251 and moves in the paper feed guide 253 of the paper feed mechanism 213, the leading end portion thereof is the sensor. The photosensitive drums 201a, 201b, 201c, and 201d of the respective image stations Pa, Pb, Pc, and Pd start to rotate by a detection signal output from this sensor (not shown). The drive roller 211 is also driven at the same time, and the transport belt 208 is driven in the direction of arrow Z in FIG. When the transfer material 206 is guided by the paper feed guide 253 and placed on the conveyor belt 208, it receives corona discharge from the adsorption charger (not shown) and the conveyor belt 20.
8 is surely adsorbed on.

The photosensitive drum 2 is driven at a predetermined timing based on the driving timing of the registration roller pair 280.
The image forming process for 01a, 201b, 201c, and 201d is sequentially started. That is, a magenta image is formed on the photosensitive drum 201a of the first image station Pa and a photosensitive drum 201b of the second image station Pb is formed.
, A yellow image is formed on the photosensitive drum 201c of the third image station Pc, and a black image is formed on the photosensitive drum 201d of the fourth image station Pd. Since the principle of image formation in these image stations Pa, Pb, Pc and Pd is already well known as the Carlson process, the description thereof will be omitted.

The transfer material 2 is moved by the movement of the conveyor belt 208.
06 is the first to fourth image forming stations Pa to Pd
Of the photosensitive drums 201a to 201d are sequentially conveyed toward the fixing device 207, and the image forming units are formed on the transfer material 206 by the transfer dischargers 204a, 204b, 204c and 204d of the image stations. The visible images of the respective colors formed in step 1 are sequentially transferred so as to be superimposed and the color images are combined. After the transfer material 206 has passed through the fourth image forming station Pd, the transfer material 206 is neutralized by the above-mentioned static eliminator (not shown) to which an AC voltage is applied, and the transfer belt 206 is conveyed.
Separated from 8. The transfer material 206 separated from the transport belt 208 is sent to the fixing device 207, and after the transferred visible image is fixed in the fixing device 207, the transfer material 206 is discharged from the transfer material discharge port 214 to the discharge tray 271. Thus, one image forming cycle is completed.

Next, details of the drive roller portion will be described. In FIG. 12, a thermistor 221 is arranged on the peripheral surface of the drive roller 211 as a temperature detecting means. Figure 1
2 shows the vertical cross section. Drive roller 211
Is composed of a hollow roller base material 211b and a rubber material 211a integrally molded around the hollow base material 211b, and is bridged to the side plates 224a and 224b through bearings 223a and 223b. 225 is integrally attached. Further, the gear 225 is a gear 22 that is integrally attached to the output shaft of the stepping motor 227.
6 is engaged, and when the stepping motor 227 rotates, the drive roller 211 rotates and the conveyor belt 208 moves.

The thermistor 221 is the drive roller 2
A spring 221a urges approximately the center of 11 with a constant pressure.

With the above configuration, the stepping motor 227
The control method of will be described. The stepping motor is a motor that rotates only a predetermined angle when a pulse input is applied to the motor, and the speed can be easily and accurately variably controlled by changing the frequency of the pulse train to be applied.

The gear ratio of the gear is room temperature TH.degree.
The pulse input of fpps is given at (° C.) (3 in this embodiment).
5,000 pps) and the conveyor belt moves at a predetermined conveyor speed
To be set. Where each station interval L₁To
200mm, diameter D of driving roller₁Is 40mm in name,
Made of rubber (coefficient of linear expansion C_G= 20 x 10^-Five/ ° C) and
Then, the support portion of the photosensitive drum is made of iron (coefficient of linear expansion C_S= 1 x 1
0^-Five / ° C), in the conventional example, the above-mentioned temperature is room temperature 20
First image scan when changing 15 degrees from ℃ to 35 ℃
Station Pa magenta and fourth image station Pd
The black color shift amount ΔL is ΔL = L₁× 3 × {(D₂/ D₁)-(1 + C_S× 15de
g)} D₂= D₁× {1 + C_G× 15 deg} (1) Substituting the above values, the amount of color shift is very large.
ΔL = 1.71 mm. Where again C_S≪C_Gso
Therefore, the equation (1) is ΔL ≈ L₁× 3 × D₂/ D₁ D₂= D₁{1 + C_G× 15deg} (2) This is because the drive roller diameter is D depending on the temperature.₁→ D₂Up to
Since the rotation angle is constant, the conveyor belt speed increases.
It is considered that this is a color shift that has occurred.

In this embodiment, this change is corrected by controlling the rotation angle of the drive roller. Pulse motor 21 after correction
When the pulse train input applied to 7 is f ₂ pps, f ₂ is expressed by the following equation.

F ₂ pps = f × D ₁ / D ₂ (3) Substituting the above numerical values for f = 3000 pps, f ₂ = 3000 × 40 / {40 × (1 + 20 × 10 ⁻⁵ ×)
15)} = 2991 pps When the temperature rises by 15 deg, the pulse input applied to the pulse motor is changed from 3000 pps to 2991 pps. As a result, the amount of color misregistration becomes almost zero.

That is, the temperature change is measured by the output of the thermistor 221. Based on the measured value, the frequency of the pulse train applied to the pulse motor is determined by the formula (3) (the formula (1) is modified to reduce the error), and a predetermined pulse train is applied to the pulse motor.

This series of operations is shared by the speed control circuit of FIG. 12, and this control prevents the conventional color misregistration (top margin misregistration).

<Fourth Embodiment> Next, a fourth embodiment of the present invention will be described with reference to FIGS. 14 and 15. The same parts as those in the third embodiment are designated by the same reference numerals and the description thereof will be omitted.

The present embodiment is different from the third embodiment in the structure of the driving roller portion, and is used in the image forming apparatus as shown in FIG. 11 similarly to the third embodiment.

FIG. 14 shows a schematic structure of the drive roller portion of this embodiment. As shown in FIG. 14, a heater 220 as a temperature adjusting means is arranged inside the driving roller 211, and a thermistor 221 as a temperature detecting means is arranged on the peripheral surface. The drive roller 211 includes a hollow roller base material 211b and a rubber material 2 integrally molded around the hollow roller base material 211b as in the third embodiment.
11a, and the side plate 224 via the bearings 223a and 223b.
It is bridged to a and 224b, and a gear 225 is integrally attached to one end thereof to transmit the drive.

The heater 220 is a rod-shaped heater inserted in the hollow portion of the drive roller 211 and does not rotate,
Power is supplied from both ends by power supply units 222a and 222a to generate heat.

The thermistor 221 is the driving roller 2
A spring 221a urges approximately the center of 11 with a constant pressure.

With the above construction, as shown in FIG. 15, the roller temperature is detected by the thermistor 221. If the temperature is lower than the set temperature T ₁ , the heater 220 is energized to drive the drive roller 211.
To heat. When the temperature is equal to or higher than the set temperature, the power supply is stopped. Thus, in this embodiment, the so-called ON
The temperature of the drive roller 211 is controlled to a substantially constant temperature by the / OFF control. As is well known, the accuracy of this type of temperature control can be improved by predictive control in consideration of overshoot, delay, etc., but the description thereof is omitted here.

As described above, if the temperature of the surface of the driving roller is kept constant, the diameter of the driving roller 211 does not largely change as in the conventional case due to the temperature rise in the apparatus and the installation environment of the apparatus.

Therefore, for example, the distance L ₁ between the stations is 200 mm, and the diameter D _{1 of the} driving roller is 40 m.
m, material is rubber (coefficient of linear expansion C _G = 20 × 10 ^-5 / ° C)
And the support portion of the photosensitive drum is made of iron (coefficient of linear expansion C _S = 1 ×
10 ⁻⁵ / ° C.), in the conventional example, the magenta of the first image station Pa and the fourth image station P when the temperature changes by 15 deg from room temperature 30 ° C. to 45 ° C.
The color shift amount ΔL of black of d is as follows.

For example, if the setting is such that ΔL = 0 at 30 ° C., at 45 ° C., the top margin shift occurs as much as expressed by the following equation.

ΔL = L ₁ × 3 × {(D ₂ / D ₁ ) − (1+
C _S × 15 deg)} D ₂ = D ₁ × {1 + C _G × 15 deg} Substituting the above numerical values, the color misregistration amount is very large, and ΔL = 1.71 mm.

However, according to this embodiment, since the driving roller is kept at a constant temperature, there is no top margin deviation due to the diameter change of the driving roller, and the color deviation occurs due to the temperature change of each station interval. When calculated in the same manner, ΔL = L ₁ × 3 (1 × 10 ⁻⁵ × 15) = 0.09, which makes it possible to suppress the color misregistration sufficiently small.

Further, in this embodiment, the heating control is shown, but it goes without saying that the color misregistration can be suppressed in the same manner by cooling control by cold air or the like as a method for keeping the temperature of the driving roller constant.

Further, in view of the nature of the present invention, it is desirable to prohibit the printer operation of the apparatus when the temperature of the driving roller is largely different from the set value.

<Fifth Embodiment> Next, a fifth embodiment of the present invention will be described with reference to FIGS. FIG. 16 is a vertical sectional view showing the image forming apparatus of the present invention. In this example,
Electrophotographic laser beam color printer (L
This is applied to a BP device).

The LBP apparatus generally has a plurality of image forming stations juxtaposed to each other and uses modulated laser light as a light source to form toner images of three colors, for example, magenta, cyan and yellow, in an electrophotographic process. However, a toner image of each color is transferred onto a transfer material one after another, and a full color image is obtained by using a subtractive color mixing method. Such an LBP device is well known to those skilled in the art. Detailed description is omitted.

With reference to FIG. 16, the configuration and operation mode of the LBP device of this embodiment will be described. In this embodiment, LBP
The apparatus 1 includes three image forming stations I, II and II.
Below the image forming stations I, II, and III, there is arranged a transfer material conveying means 39 having a conveyor belt 26 for conveying the transfer material, and an outlet portion of the conveying means 39. In order to thermally fix the image on the transfer material on the transfer material, a fixing unit 56 including a pair of heat rollers 56a and 56b is arranged. Each image forming station I, I
I and III are means for forming an image, for example, an image carrier rotating at a constant speed, in the present embodiment, electrophotographic photosensitive drums 11, 12, 13 and chargers 14, 15, 16,
Developing devices 17, 18, 19 and transfer chargers 20, 21, 2
2, and cleaners 23, 24, 25.

The image signals input to the respective image forming stations I to III are composed of three kinds of image signals obtained by color-separating the original recording image into red, blue and green components, and the image signals of the respective color components are continuous. And is transferred to the image forming station.

Further, the image signal is input in the order of red, blue and green components at a certain fixed interval. When an image signal is input to the LBP device 1 from an external device, the image signal of the green component sent first is the image station I.
Is input to the laser scanner 2.

The laser scanner 2 irradiates the rotating polygon mirror with the laser light 5 modulated and emitted from the built-in laser diode based on the image signal of the green component to bring it into a parallel scanning state, and then the folding mirror 8 The image is projected and imaged on the surface of the photosensitive drum 11 which is rotating at a constant speed via, and scanning is performed in the direction perpendicular to the rotating direction of the photosensitive drum 11. By the operation of the laser scanner 2 as described above, the charger 1
At 4, the latent image of the green component of the recorded image is formed on the surface of the photosensitive drum 11 that is uniformly charged.

The latent image formed on the photosensitive drum 11 is developed with magenta toner filled in the developing device 17 and visualized. The magenta toner image on the photosensitive drum 11 obtained by the development is transferred onto the transfer material 46 placed on the transfer belt 26 and conveyed by the action of transfer electrolysis applied by the transfer material charger 20.

When the image signal of the green component is completed, the image signal of the red component is input to the laser scanner 3, and the same process as described above is performed, and the image is formed on the photosensitive drum 12 by the cyan toner in the developing device 18. A cyan toner image is formed. The cyan toner image is transferred onto the magenta toner image on the transfer material 46 conveyed from the direction of the photosensitive drum 11 by the conveying belt 26 so as to be superposed.

When the red component image signal ends, the blue component image signal that is subsequently input is input to the laser scanner 4, and a yellow toner image is formed on the photosensitive drum 13 through the same process as described above. It The yellow toner image is transferred so as to be superposed on the cyan toner image on the transfer material 46 which is carried by the carrying belt 26 in the direction of the photosensitive drum 12.

By the above operation, the toner images of magenta, cyan, and yellow are transferred onto the transfer material 46 in a multi-layered state, and then the transfer material 46 is sent to the fixing means 56 by the conveyor belt 26.

The temperature of the photosensitive drums 11, 12, 13 is detected by the temperature sensors 71, 72, 73. The microcomputer in the LBP device 1 compares the detected temperature with the set temperature to detect the temperature of the photosensitive drums 11, 12 ,. The heaters 74, 75, and 76 built in 13 are subjected to ON / OFF control to maintain a constant temperature. This temperature control is in operation even when the power switch of the device 1 is turned off in order to shorten the rise time of the LBP device 1.
That is, it is in the operating state unless the current supply is cut off by pulling out the outlet of the device 1.

Now, the transfer material 4 conveyed to the fixing means 56.
6 is heated rollers 56a and 56b in the fixing means 56.
While passing through the gaps, heat and pressure are applied to the toner images of the respective colors, and the toners of the respective colors are melted and subjected to subtractive mixing, thereby forming a full-color image and the transfer material 46.
Fixed on the surface of.

Here, each of the image forming stations I to II.
If the toner image of I is not transferred to the same position of the transfer material 46 at all times, color shift will occur in the obtained image and the image quality will be significantly deteriorated.
Is controlled so that the rotational peripheral speed of the photosensitive drum 11, the conveying speed of the conveying belt 26 and the conveying speed of the conveying belt 26 are matched with each other with extremely high accuracy. An encoder is provided on the rotation shaft, and the wow and flutter can detect the rotation speed of each member.

Next, the transfer material conveying means 39 of the LBP device 1
Will be described in more detail.

The transfer material 46 cut into a standard size is
It is loaded in the cassette 45. The cassette 45 is LBP
When mounted in the device 1, the cassette 45 pushes the cassette detection switch 47 and transmits a cassette mounting signal to the microcomputer in the LBP device 1.

When the cassette 45 is mounted on the LBP device 1, the transfer material 46 comes into pressure contact with the feed roller 48. When the feed roller 48 rotates, the transfer material 46 is pulled out of the cassette 45 due to the difference between the frictional force between the feed roller 48 and the transfer material 46 and the frictional force between the transfer materials 46. The transfer material 46 is conveyed while being sandwiched between the registration rollers 49, and the leading end portion of the transfer material 46 irradiates the photo sensor 51 from the lamp 50 along the optical path between the lamp 50 and the photo sensor 51 provided for detecting the transfer material leading end. It is sent out until the light is blocked. When the front end of the transfer material blocks the optical path from the lamp 50 to the photo sensor 51, the registration roller 49 stops rotating with the transfer material 46 being nipped.

When the latent image is formed on the surface of the photosensitive drum 11 by the operation of the laser scanner 2, the timing is adjusted so that the magenta toner image obtained by developing the latent image can be transferred, and then the registration roller is again formed. 49 rotates and sends the sandwiched transfer material 46 onto the conveyor belt 26.

The conveyor belt 26 is made of a transparent or translucent resin material such as polyurethane, and the surface thereof is charged by using the adsorption charger 33 during operation so that the transfer material 46 can be stably conveyed. Then, the transfer material 46 is transferred onto the conveyor belt 26.
Electrostatically adsorb. Further, the transfer belt 46 and the transfer material 46 are pressed by the driven roller 34 and the pressing roller 52 so that the transfer material 46 sent out from the registration roller 49 is favorably electrostatically adsorbed on the transfer belt 26 without waviness. It

Developing devices 17 and 1 containing toners of respective colors
Lamps 27, 29, and 31 are provided at the bottoms of 8 and 19, respectively, so that approximately parallel light can be projected onto the surface of the conveyor belt 26. On the other hand, the lamps 27, 2 of the conveyor belt 26
Photodiodes 28, 30, and 32 are provided inside the portions projected by the light sources 9 and 31, respectively, so that the amount of light emitted from the lamps 27, 29, and 31 passing through the conveyor belt 26 can be detected.

A transfer material 46 in which toner images of respective colors are successively superposed from the photosensitive drums 11, 12, 13 are transferred.
Is separated from the surface of the conveyor belt 26 by the action of the separation claw 36, enters the fixing unit 56 through the conveyor path 53, and is then discharged to the tray 60 after the image is fixed.

On the other hand, the conveyor belt 26 from which the transfer material 46 has been separated is cleaned and discharged by the conductive blade 37 for the toner and paper dust adhering to the surface.

The above-mentioned members of the lamps 27, 29, 31, the photodiodes 28, 31, 32, the conveyor belt 26, the adsorption charger 33, the driven roller 34, the drive roller 35, the separation claw 36, and the conductive blade 37 are as follows. The transfer material conveying means 39 is assembled on the frame 38.

The transport means 39 is supported by the rollers 41 provided on the lifter frame 40 via the frame 38. The lifter frame 40 is supported by the cam 43, and the height of the lifter frame 40 can be changed as shown in FIGS. 16 and 17 by rotating the cam 43 by the rotation of the cam shaft 42. The cam shaft 42 is connected to the position sensor, and it is possible to detect the position of the lifter frame 40 based on the signal output state from the position sensor. Further, the cam shaft 42 is connected to a drive source via a clutch mechanism controlled by a microcomputer in the LBP device 1.

The lifter frame 40, the rollers 41, the cams 42, the cams 43, etc. constitute an elevating means 44 for changing the height position of the conveying means 39. The elevating means 44 and the conveying means 39 are set so that the conveying belt 26 and the surfaces of the photosensitive drums 11, 12, 13 are brought into contact with each other when the conveying means 39 is held at the highest position by the elevating means 44, as shown in FIG. Has been done.

Next, as shown in FIG. 17, the transport unit 3
By slightly lowering the 9th position, the conveyor belt 26 and the respective photosensitive drums 11, 12, 13 are brought into non-contact with each other.

In this embodiment, the elevating means 44 during image formation.
By raising the conveying means 39 by
The above-mentioned image forming process is carried out with each of the photosensitive drums 11, 12, and 13 in contact with each other. However, since the time during which the photosensitive drums 11 to 13 are in contact with one place on the conveyor belt 26 is a minute time, A large amount of the temperature-controlled heat of the drums 11 to 13 is not received at one place where the conveyor belt 26 is located.

However, during non-image formation, that is, when the photosensitive drums 11 to 13 and the conveyor belt 26 are in contact with each other in a stopped state, as described above, for example, the power switch of the apparatus 1 is turned off. Even the photosensitive drums 11 to 1
3 is under temperature control. Therefore, at night or the like when there is no user, one place where the conveyor belt 26 is present continues to receive the heat of the photosensitive drums 11 to 13.

In addition, the conveyor belt 26 may be made of a resin material having a low elastic modulus in order to avoid a problem such as a positional deviation of an image which is influenced by the elasticity of the conveyor belt 26. When the position portion is softened and deformed due to the heat effect of time, it is difficult for the softened and deformed portion to return to its original state due to elasticity, and permanent deformation is likely to occur. When such a process is repeated, the transport belt 26 becomes a wavy state, the transfer material 46 to be electrostatically attracted onto the transport belt 26 does not come into close contact, and the transfer material 46 floats on the transport belt 26. The photosensitive drum 1 is transported while being supported by
Since the toner is formed in the process of transferring the toner images formed on the rollers 1 to 13, the transfer current generated between the transfer chargers 20, 21 and 22 and the photosensitive drums 11, 12 and 13 facing the transfer chargers is disturbed. Occasionally, the toner image may not be normally transferred onto the transfer material 46.

Alternatively, if the transfer material 46 floats at its tip, a jam of the transfer material may occur at the contact portion between the photosensitive drums 11 to 13 and the conveyor belt 26. In addition, even if this is not the case, the conveyor belt 26
Waviness caused uneven transport speed, and each station I,
In II and III, a color shift may occur between the toner images transferred onto the transfer material 46, and in any case, the image quality of the obtained image is significantly deteriorated.

In this embodiment, at the time of non-image formation, as shown in FIG. 17, the conveying means 39 is lowered by the elevating means 44 so that the conveying belt 26 is moved to the photosensitive drums 11 to 1.
3 is in a non-contact state with the photosensitive drum 11
It is possible to prevent the transfer belt 26 from being deformed by the heat of 13 to 13 and to stably and satisfactorily transfer the transfer material 26 and transfer the toner image onto the transfer material during image formation. The temperature of the photosensitive drums 11 to 13 during non-image formation is set so that the conveyor belt 26 is not deformed by heat.

Next, using the flowchart of FIG.
The operation control of the image forming apparatus in this embodiment will be described. First, the user turns on the power switch of the LBP device 1.
When N, the fixing unit 56 is moved to a warm-up state such as heating. At this time, the photosensitive drums 11 to 13 have already been maintained at a predetermined temperature by being temperature-controlled regardless of whether the power switch is ON or OFF. Is in a state. Next, in response to a copy start signal from the user, the elevating means 44 raises the transfer material conveying means 39 (conveying unit UP),
The conveyor belt 26 is brought into contact with the photosensitive drums 11 to 13.

After that, the transfer material 46 is fed by the feed roller 48, and is conveyed to the conveying means 39 by the registration roller 49 at a predetermined timing, electrostatically adsorbed on the conveying belt 26 and conveyed, and then the transfer material 46 is conveyed. Transfer the toner image to
The operation of fixing and discharging the paper is as described above.

In this embodiment, the transfer material detecting sensors 50, 5
The microcomputer in the apparatus 1 determines whether or not the transfer material 46 is conveyed based on the detection signals from 1, 54, 55, 57 and 58. When the occurrence of a jam of the transfer material is determined and detected, the operation is performed. The jam is displayed on the board. When the microcomputer determines that the set number of copies set by the user has been successfully completed, the transport means 3
9 is lowered by the elevating means 44 (transport unit DOWN
N), the conveyor belt 26 is brought into non-contact with the photosensitive drums 11 to 13.

By repeating the above operation, the conveying belt 26 is not affected by the heat from the photosensitive drums 11 to 13 for a long time, so that the deformation due to the heat is prevented. However, if the interval between the copies is relatively short, the raising and lowering of the conveying means 39 will be a loss time, so during the time when the conveying belt 26 does not deform even if it receives heat, the route is shown by the dotted line in FIG. The descending operation of the control means 39 may be performed by the timer control, and the same descending operation can be obtained.

In the above, the conveyance belt 26 is prevented from being deformed by raising and lowering the conveying means 39.
A similar descent can also be obtained by moving up and down on the ~ 13 side, which may be done.

<Sixth Embodiment> Next, a sixth embodiment of the present invention will be described with reference to FIGS. In addition, the same parts as those of the fifth embodiment are designated by the same reference numerals and the description thereof will be omitted.

FIG. 19 is a schematic vertical sectional view showing a transfer material conveying means in the embodiment 5 of the image forming apparatus of the invention.
In FIG. 19, the transfer belt 26 of the transfer material transfer unit 39
The state indicated by the alternate long and short dash line indicates the time of image formation, and the transport belt 26 wound around the drive roller 35, the driven roller 34, and the guide rollers 36a and 36b is not the same as the transport belt 26 of the driven roller 34. By pushing the driven roller 34 to the outside by the cam 80 provided on the side opposite to the contact side,
The photosensitive drums 11 to 13 in a stretched state so as not to come loose.
Is in contact with.

At the time of image formation, the conveyor belt 26 conveys a transfer material (not shown) that has been sent upstream and placed thereon by electrostatically adsorbing and supporting it, and at the contact portion with the photosensitive drums 11 to 13. Transferring the toner images of the respective colors formed on the photosensitive drums 11 to 13 onto the transfer material is the same as in the fifth embodiment.

Then, at the time of non-image formation, the cam 80 pushing the driven roller 34 to the outside is rotated inward by 180 degrees from the position indicated by the one-dot chain line to the position indicated by the solid line, and the conveyor belt 26 is also inclined from the position indicated by the one-dot chain line. Move to the position of the solid line retracted inward. As a result, the conveyor belt 26 is loosened and brought into a non-contact state in which it is separated from the photosensitive drums 11 to 13, so that the conveyor belt 26 is not affected by the temperature-controlled heat of the photosensitive drums 11 to 13 as described above. .
As a result, also in this embodiment, it is possible to prevent permanent deformation of the conveyor belt 26 due to heat.

FIG. 20 shows a flow chart of device operation control in this embodiment. In the present embodiment, the steps of raising (conveying unit UP) and lowering (conveying unit DOWN) the transfer material conveying means 39 in the flowchart of FIG. Others are the same.

According to the present embodiment, in addition to the above-mentioned effects, by holding the conveying belt 26 around the driven roller 34, the driving roller 35 and the like in a tensioned state at the time of image formation, these rollers 34, 35 are held. Deformation due to the pressing force at the contact portion with the like can be prevented at the same time as releasing the contact of the conveying belt 26 with the photosensitive drums 11 to 13 because the conveying belt 26 is loosened and the pressing force is released at the time of non-image formation. There is a merit that will be possible.

In the above, the photosensitive drum 1 of the conveyor belt 26 is
Although only the driven roller 34 is moved in order to bring it into contact with or separate from the driving rollers 1 to 13, the driving roller 35 may be moved, or both of them may be moved. Further, although the driven roller 34 is moved by the mechanism of the cam 80, the conveying belt 26 and the photosensitive drums 11 to 13 can be brought into contact state or non-contact state, and the conveying belt 26 is stretched in the contact state to make non-contact state. Any mechanism may be used as long as it can be loosened.

<Seventh Embodiment> Next, a seventh embodiment of the present invention will be described with reference to FIG. In this embodiment, auxiliary heaters 10M, 10C, 10 serving as auxiliary heating means after each image forming station serving as image forming means of the conventional apparatus shown in FIG.
Y and 10K are arranged. The auxiliary heater 10
M, 10C, 10Y, and 10K keep the transfer material P warm by being maintained at a temperature that does not melt the toner transferred onto the transfer material P in each image forming station.

In the image forming apparatus having such a structure,
When the transfer material P is sent from the paper feed cassette 407, the first image is formed on the transfer material P in the first image forming station Pm. Next, the transfer material P is sent to the second image forming station Pc, but the toner of the first image formed on the transfer material P is not melted by the auxiliary heater 10M provided between Pm and Pc on the way. It is warmed to a certain degree. Then, when the transfer material P reaches the second image forming station, the second image is formed on the transfer material P, and then heated by the auxiliary heater 10C to such an extent that the toner on the transfer material P is not melted. After that, the auxiliary heater 10Y is formed after the third image formation, and the auxiliary heater 10K is formed after the fourth image formation.
The toner on the transfer material P is warmed to such an extent that it is not melted, and finally the fixing device 408 fixes the toner. Here, in the process up to fixing, the unfixed toner image on the transfer material P has four auxiliary heaters 10M, 10C, 10Y, 1
It has been warmed to some extent by 0K. Therefore, the fixing device can perform sufficient fixing without requiring a large amount of heat as in the conventional case. In addition, when a transfer material having a large basis weight that requires a larger amount of heat than usual is used, or even when fixing is performed at a high speed, it is not necessary to set the roller surface temperature to be extremely high. Does not excessively raise the temperature or shorten the life of the roller.

<Embodiment 8> Next, an embodiment 8 of the invention will be described with reference to FIG. In addition, the same parts as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted. This embodiment differs from the first embodiment in that the auxiliary heater 10M is provided only between the first image forming station Pm and the second image forming station Pc.

In such an image forming apparatus, as in the first embodiment, while the first image is formed on the transfer material P and is sent to the second image forming station Pc, the transfer material P is an auxiliary heater. The toner is heated by 10M to such an extent that the toner does not melt. After that, the second, third, and fourth images are sequentially formed on the transfer material P, and are fixed by the fixing device 408.

In this embodiment, unlike the seventh embodiment, only one auxiliary heater is provided after the first image forming station Pm for the following reason.

Generally, in a color image forming apparatus, since the toner layer becomes thick due to multiple transfer, heaters are provided in the fixing roller 411 and the pressure roller 412 respectively to supply heat from both the front and back surfaces of the transfer material P. Although many methods are used, when fixing a color image in this heating method, heat is supplied from the fixing roller 411 so that the fourth, third, second, and first toner layers are sequentially arranged in order from the top. You will receive the amount of heat. Heat is also supplied from the pressure roller 412, but most of it is taken by the transfer material P. In particular, a transfer material having a large grammage has a strong tendency that the upper toner layer is sufficiently melted when fixing is performed, but the lower toner layer is apt to be insufficiently melted and peeled off from the transfer material. There was a case where it ended up.
Therefore, in this embodiment, the amount of heat supplied is minimized by previously transmitting heat to the first toner layer, which is the most difficult to transfer heat, by the auxiliary heater 10M after image formation. In this embodiment, the fixing property tends to be slightly worse than in the first embodiment, but good results can be obtained as compared with the conventional example. Become Further, the cost can be suppressed to the necessary minimum as compared with the first embodiment.

<Ninth Embodiment> Next, a ninth embodiment of the present invention will be described with reference to FIGS. In addition, the same parts as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted. In this embodiment, the output level of the digital pixel signal for each pixel is integrated by the video count method during copying to control the number of auxiliary heaters to be lit.

FIG. 23 is a diagram showing a schematic structure of this embodiment. An image signal input from the reader is A / D converted, and the output level of the digital signal is integrated for each pixel to obtain a video count number. This video count is CP as shown in Fig. 24.
The auxiliary heater is turned on by U, and the auxiliary heater is turned on accordingly. Here, in the color image forming apparatus, since the toner layer is thick due to the multiple transfer and the heat is most difficult to be transferred to the lowermost toner layer (first image), 10 M is supplied when one auxiliary heater is lit, and 2 M when two auxiliary heaters are lit. Is 10
When M and 10C are three, 10M, 10C and 10Y are turned on respectively.

As described above, when the amount of image information is small and the amount of heat required for fixing is small, the auxiliary heater is not turned on, and the number of auxiliary heaters to be turned on increases as the amount of image information increases. Good fixing can be achieved by supplying only a limited amount of heat, and effective supply of heat can be performed.

<Embodiment 10> Next, Embodiment 10 of the present invention.
Will be described with reference to FIGS. 25 and 26. The same parts as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 25, reference numeral 416 denotes a conveyor belt which is a transfer material guiding means, and is divided into a plurality of small belt units, which collectively form one large belt unit. As shown in FIG. 26, each small belt unit is immovable with respect to the moving direction (arrow A) of the transfer material (hereinafter referred to as a stationary belt unit).
416a, 416c, 416e and 416g, and those movable in the direction of the arrow A (hereinafter, movable belt units) 416b, 416d and 416f. The ends of the movable belt units 416b, 416d, 416f on the side of the fixing device 408 are fixed to the side of the fixing device 408 movably arranged in the direction of arrow A, and the direction of the fixing device 408 in the direction of arrow A is fixed. It moves in the direction of arrow A along with the movement. The ends of the movable belt units 416b, 416d, 416f on the transfer belt 406a side are axially supported on the metal rod 417 in the width direction (arrow B) of the transfer material. Is a stationary belt unit 416a, 416c, 416e, 4
It is adapted to move in the elongated hole portion H by being guided by the elongated hole portion H formed in the side surface portion of 16 g extending in the direction of arrow A. The length of each belt unit 416 in the direction of arrow A is larger than half the length of the maximum transfer material size in the vertical direction and smaller than the length of the maximum transfer material size in the vertical direction, and the movable belt units 416b, 416d, 416f. The maximum length of the belt unit when is moved to the front in the direction of the arrow A is larger than the maximum transfer material size.

In a color image forming apparatus provided with such a conveyor belt unit, when forming an image on plain paper, normally, the machine speed Vp and the conveyor belt 416 and the speed Vf of the fixing device 408 are driven at the same speed. Therefore, the metal rod 417 is at the position of point C in FIG. 25, and the length of the belt unit 416 in the arrow A direction is the minimum. If a transfer material that is longer than the distance between the transfer part and the fixing part is sent in this state, the image is disturbed due to the speed difference between the transfer part and the fixing part even if the transfer material is present on the transfer part and the fixing part at the same time. There is no. Since image formation is usually performed in this state, the size of the entire image forming apparatus can be small.

Next, when an image is formed on a transfer material having a large basis weight, the fixing unit requires a larger amount of heat, so the speed of the fixing unit is slowed down and the fixing time is lengthened. However, the shortest length of the belt unit 416 in the direction of arrow A is larger than half the length of the maximum transfer material size in the vertical direction and smaller than the length of the maximum transfer material size in the vertical direction. If the speed Vf of the fixing unit is slowed down, a difference occurs between the speed Vf and the machine speed Vp, which causes a problem that the image is disturbed when the maximum transfer material size is fixed. Therefore, when fixing a transfer material having a large basis weight, the metal rod 417 is manually or automatically moved to the position of point D as shown in FIG. Then, the movable belt unit 416
b, 416d, 416f and the fixing device 408 are moved by half the maximum transfer size, and the lengths of the transfer section and the fixing section are longer than the maximum length of the transfer material in the vertical direction. In this state, if an image of a transfer material having a large basis weight and a maximum transfer material size is formed, the image is formed at the machine speed Vp until the transfer material P leaves the transfer portion, and the transfer material P is completely transferred. When the transfer material P comes out, in other words, the transfer material P is immovable belt units 416a, 416c,
416e and movable belt units 416b, 416d, 4
The speed Vf of each belt unit and the fixing device 8 can be simultaneously delayed by a speed varying device (not shown) when all of them are placed on 16f. As a result, the aircraft speed V
Disturbance of the image due to the difference between p and the fixing unit speed Vf does not occur, and even when a large amount of heat is required for fixing, such as when using a transfer material having a large basis weight and a maximum transfer material size,
Good fixing became possible. Even in this case, the size of the apparatus can be reduced because only the part where the fixing device 408 is provided is projected without increasing the size of the entire apparatus.

<Embodiment 11> Next, an embodiment 11 of the present invention.
Will be described with reference to FIGS. 27 and 28. The same parts as those of the tenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 27, 416g and 416h are conveyor belts, and the conveyor belt 416g is longer than half of the maximum transfer material size in the vertical direction and smaller than the maximum length of the maximum transfer material size in the vertical direction. Also, the conveyor belt 4
In 16g, the end portion on the transfer belt 406a side is movable up and down, and the rotation speed of the belt is the same as the machine speed Vp. On the other hand, the conveyor belt 416h is larger than the maximum length of the transfer material in the longitudinal direction, and the angle between the conveyor belt 416h and the conveyor belt 416g is 60 ° or more, and the end portion on the transfer belt 6a side can be moved left and right. There is. Further, each of the conveyor belts 416h and 416g is connected to a suction means (not shown) so that the transfer material P can be sucked. Further, the fixing device 408 can be moved up and down by a guide plate (not shown).

In a color image forming apparatus provided with such two conveyor belts, usually, when forming an image on plain paper, the fixing device 408 is arranged on the upper portion as shown in FIG. 27, and the transfer belt of the conveyor belt 416g. The end portion on the 406a side is lowered and the transfer belt 406h of the conveyor belt 416h is lowered.
The end portion on the a side is moved to the fixing device 408 side. That is, in the case of plain paper, the transfer material P is guided to the conveyor belt 416g side. If plain paper that is longer than the distance between the transfer unit and the fixing unit is fed in this state, even if the transfer material P is present at the transfer unit and the fixing unit at the same time, the machine speed Vp and the fixing speed Vf.
Since they are the same, no image distortion occurs.

Next, when an image is formed on a transfer material having a large basis weight, the fixing device 408 is manually or automatically moved downward as shown in FIG. Along with this, a conveyor belt 416 is moved by a conveyor belt position varying device (not shown).
The transfer belt side end of g is raised upward, and the conveyor belt 41
The end portion of the 6h side of the transfer belt 406a is the transfer belt 406.
Automatically move to side a. That is, in the case of a transfer material having a large basis weight, the fixing device 408 moves downward and the transfer material P is guided to the transport belt 416h. In this state, if an image of a transfer material having a large basis weight and a maximum transfer material size is formed, the image is formed at the machine speed Vp until the transfer material P leaves the transfer portion, and then the transfer material P is conveyed by the conveyor belt. You are led to 416h. The conveyor belt 416h is initially rotated at the same speed as the machine speed Vp, and when the transfer material P is completely removed from the transfer section, in other words, when the transfer material P is completely placed on the conveyor belt 416h, the conveyor belt 416h.
And the speed Vf of the fixing device can be simultaneously delayed by a speed varying device (not shown), and transfer of the maximum transfer material size having a large basis weight without causing image disturbance due to the difference between the machine speed Vp and the fixing speed Vf. Even when a large amount of heat is required for fixing, such as when using a material, good fixing is possible.

<Embodiment 12> Next, Embodiment 12 of the present invention.
Will be described with reference to FIGS. 29 and 30. The same parts as those of the tenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In FIG. 29, 416i, 416j, 41
6k is a conveyor belt, and the conveyor belt 416i is longer than half the length of the maximum transfer material size in the vertical direction and smaller than the length of the maximum transfer material size in the vertical direction.
The end portion on the transfer belt 406a side is movable up and down. The rotation speed of the conveyor belt 416i is the same as the machine speed Vp. On the other hand, the conveyor belt 416
j and 416k are belts having the same length as the conveyor belt 416i, and are arranged in a dogleg shape as shown in FIG. 29 so that the respective belts rotate independently. The end portion on the 406a side is movable left and right. Reference numeral 418 denotes a conveyance guide which is used to smoothly convey the transfer material P from the conveyance belts 416j to 416k.
It is located between 16j and 416k. Further, each of the conveyor belts 416j and 416k is connected to a suction unit (not shown) so that the transfer material P can be sucked. Further, the fixing device 408 can be slightly moved up and down by a guide plate (not shown).

In a color image forming apparatus provided with such a conveyor belt, when an image is normally formed on plain paper, as shown in FIG. 29, the transfer belt 4 of the conveyor belt 416j is used.
The end on the 06a side is lowered, and the end on the transfer belt 406a side of the transport belt 416j is moved to the fixing device 408 side. That is, in the case of plain paper, the transfer material P is the transfer belt 4
It will be led to the 16j side. If plain paper that is longer than the distance between the transfer section and the fixing section is sent in this state,
Even if the transfer material P is present at the transfer portion and the fixing portion at the same time, since the machine speed Vp is equal to the fixing speed Vf, the image disturbance does not occur.

Next, when an image is formed on a transfer material having a large basis weight, the fixing device 408 is manually or automatically moved slightly downward as shown in FIG. Along with this, a conveyor belt position changing device (not shown) is used to convey the conveyor belt 4.
The end of 16i on the transfer belt 406a side is raised, and the end of the conveyor belt 416j on the transfer belt 406a side is automatically moved to the transfer belt 406a side. That is, in the case of a transfer material having a large basis weight, the transfer material P is the transfer belt 41.
You will be led to 6j. The transfer material P guided to the conveyance belt 416j is conveyed by the conveyance guide 418 to the conveyance belt 4
16k and then to the fixing device 408 by the conveyor belt 416k. In this state, if an image of a transfer material having a large basis weight and a maximum transfer material size is formed, the image is formed at the machine speed Vp until the transfer material P leaves the transfer portion, and then the transfer material P is conveyed. Belt 416
j and 416k. Conveyor belts 416j and 4
At the beginning, 16k was rotating at the same speed as the aircraft speed Vp,
When all of the transfer material P is removed from the transfer section, in other words, when all of the transfer material P is placed on the transfer belts 416j and 416k, the transfer belts 416j and 416k and the fixing device 4 are set.
The speed Vf of 08 is simultaneously delayed by a speed varying device (not shown), and the fixing device 408 performs fixing.
As a result, even when a large amount of heat is required for fixing such as when using a transfer material having a large basis weight and a maximum transfer material size without causing image disturbance due to a difference between the machine speed Vp and the fixing speed Vf, it is preferable. Fixation is possible.

<Embodiment 13> Next, Embodiment 13 of the present invention.
Will be described with reference to FIGS. 31 to 33. The same parts as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, as shown in FIG. 31, the blade 4
A cam 413e is attached to 13d, and a coating roller 413c
The angle with respect to is variable. By adopting such a configuration, the coating roller 41 of the blade 413d
The contact angle with respect to 3c can be set as shown in FIGS. 32 (a) and 32 (b). When the angle between the blade 413d and the coating roller 413c is small as shown in FIG. 32 (a) and the antinode portion of the blade 413d is in contact with the coating roller 413c, the mold release slips past the blade 413d. The amount of agent increases and the amount of application increases. As shown in FIG. 32B, the blade 413d and the coating roller 41
When the angle with 3c is large and the part of the blade 413d is in contact with the coating roller 411c, the amount of the release agent scraped off by the blade 413d increases,
The coating amount is small.

FIG. 33 shows a control diagram of this embodiment.
In FIG. 33, the amount of release agent applied is controlled to be variable between a color image and a monochrome image. Generally, a color image has a thicker toner layer than a black-and-white image, so that the fixing property tends to be deteriorated. Therefore, at the time of fixing, the fixing roller 411
Since the amount of toner adhered to the toner is larger than that of a black-and-white image, it is necessary to apply a large amount of release agent, and the blade is brought into contact as shown in FIG. Further, in the case of a black and white image, the toner layer is thin, so the amount of release agent applied may be small.
The blade is brought into contact as shown in (b).

As described above, by changing the contact angle of the blade between the color image and the black-and-white image, it is possible to change the amount of the release agent applied, and only when a large amount of heat is required for fixing as in the case of a color image. Not only that, the optimum amount of the release agent can be applied to a black and white image.

<Embodiment 14> Next, Embodiment 14 of the present invention.
Will be described with reference to FIGS. 34 and 35. In addition, the same parts as those of the seventh embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, a transfer material thickness detecting device as shown in FIG. 34 is provided in the paper feeding section to read the basis weight of the transfer material and control the coating amount of the release agent according to the basis weight. Then
The mold release agent is applied to a transfer material.

As shown in FIG. 34, the transfer material thickness detecting device includes a registration roller 419 that is axially supported and a registration roller 420 that is vertically movable and is pressed against the registration roller 419 by a spring 421 from above. Have When the transfer materials P having different basis weights pass between the two registration rollers 419 and 420, the position of the registration roller 420 is changed and the potentiometer 423 is moved by the clutch 422.
Then, the thickness of the transfer material P is detected.

When the basis weight of the transfer material exceeds a certain standard, the amount of heat required for fixing is larger than that for plain paper, but the fixing amount tends to be poor because the amount of heat applied during fixing is constant. Therefore, the amount of toner that adheres to the fixing roller during fixing also increases, and it is determined that a large amount of release agent needs to be applied, as shown in FIG. Further, in the case of an ordinary transfer material or a transfer material having a small basis weight, the amount of the release agent applied may be small.
The blade is brought into contact as shown in 2 (a).

By changing the contact angle of the blade in accordance with the basis weight of the transfer material as described above, it becomes possible to change the coating amount of the release agent, and the optimum release agent can be selected according to the thickness of the transfer material. Fixing can be performed with the amount of the agent applied.

<Embodiment 15> Next, Embodiment 15 of the present invention.
Will be described with reference to FIGS. 32 and 36 to 39. The same parts as those of the thirteenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the image information amount is read by the video count method at the time of copying, the release agent application amount is controlled according to the information amount, and the release agent application suitable for the image information is performed. It is a thing.

The video count system is configured to integrate the output levels of digital pixel signals for each pixel and predictably supply the required toner amount. FIG. 36 is a schematic configuration diagram of the apparatus of this embodiment, in which the input image signal from the reader is A /
D conversion is performed, and the digital pixel signal is integrated with the output level for each pixel to obtain the video count number. As shown in FIG. 37, the CPU converts the video count number into the required toner amount,
The amount of release agent applied is controlled accordingly.

In this embodiment, as shown in FIG. 38, when the image information amount is larger than a certain reference amount, the toner amount required for the image is large and the toner amount adhered to the fixing roller 411 after fixing is large. Therefore, it is determined that a large amount of release agent needs to be applied, and the blade is brought into contact as shown in FIG. 32 (b). When the amount of image information is smaller than a certain reference amount, the amount of toner required for the image is not small and the blade is brought into contact as shown in FIG.

By changing the contact angle of the blade in accordance with the amount of image information as described above, it becomes possible to change the coating of the release agent, and the fixing can always be performed with the optimum coating amount of the release agent.

<Embodiment 16> Next, Embodiment 16 of the present invention.
Will be described with reference to FIG. The same parts as those of the fifteenth embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the amount of release agent applied is controlled to be variable between a color image and a black-and-white image, and the cleaning ability of the roller surface is changed according to the amount applied. .

As described in the seventh embodiment, the amount of the release agent applied can be varied between the color image and the black-and-white image. As a result, the image quality can be improved and the oil can be efficiently consumed. . However, since the amount of release agent applied is variable, the amount of toner that adheres to the roller surface tends to increase when the amount of release agent applied is small. Although the amount of adhered toner tends to decrease, the cleaning ability of the cleaning member on the roller surface is always constant here, which means that efficient cleaning is not performed in the thirteenth embodiment. Therefore, in this embodiment, a variable pressure device is further provided on the cleaning member on the roller surface to make the pressing pressure on the roller surface variable, or a variable winding device is provided on the cleaning member on the roller surface to wind the cleaning member. Optimal cleaning was performed by varying the amount taken. That is, as shown in FIG. 39, when the amount of the release agent applied is small (when the amount of toner attached to the roller surface is large), the pressing pressure of the cleaning member is increased or the winding amount is increased to perform cleaning. Increase. On the other hand, when the amount of the release agent applied is large (when the amount of toner attached to the roller surface is small), the pressing pressure of the cleaning member is weakened, or the winding amount is reduced to weaken the cleaning effect. In this embodiment, by adopting such a configuration, it is possible to perform efficient cleaning, and as a result, it is possible to extend the life of the roller.

In this embodiment, the color image and the black-and-white image are controlled differently as in the case of the thirteenth embodiment, but the same effects can be obtained by using the fourteenth and fifteenth embodiments. .

[0189]

As described above, according to the first invention of the present application, at least one of the image carrying means and the transfer material carrying means is constituted by an endless belt member and a belt holding mechanism, and a belt support member is provided. Image formation in which the correction roller, which is one of the above, is alternately moved to the first position and the second position, and the belt member is forcibly reciprocated in the direction transverse to the belt movement direction to perform the belt deviation control. In the device,
Since the deviation speed of the belt is detected to correct the movement amount of the correction roller, deviation from the deviation control due to twisting of the apparatus or change with time can be prevented, and damage to the belt member can be prevented. .

Further, according to the second aspect of the present invention, there is provided a transfer material conveying means for sequentially conveying the transfer material to a plurality of image stations by the belt body carrying the transfer material and circulatingly moving, and driving the above belt body. Since temperature detection means for detecting the temperature of the roller and speed control means for adjusting the rotation speed of the drive roller are provided, the speed of the drive roller is controlled by the temperature of the drive roller so that color misregistration (top margin deviation) does not occur. It is possible to prevent color misregistration from occurring by using a roller of any material and provide a high-quality image.

Further, according to the third invention of the present application, there is provided a transfer material transporting means for sequentially transporting the transfer material to a plurality of image stations by means of the belt material which carries the transfer material and circulates. Since the detection means for detecting the temperature of the drive roller and the temperature control means for adjusting the roller temperature are provided to control the roller temperature so as to be kept constant, the diameter of the drive roller depends on the temperature rise in the device and the installation environment temperature of the device. Therefore, even if a roller made of any material is used, the top margin shift (color shift) can be prevented from occurring and a high quality image can be provided.

Further, according to the fourth aspect of the present invention, the entire transfer material conveying means constituted by a plurality of rotatable belt holding mechanisms such as an endless conveying belt and rollers for holding the same can be raised or lowered, or at least. By making one belt holding mechanism swingable, the conveyor belt can be brought into contact with and separated from the image carrier, and the contact between the conveyor belt and the image carrier can be made during non-image formation and when the conveyor belt is stopped. Since it is released to make it non-contact, it is possible to avoid being affected by heat for a long time from the temperature-controlled image carrier, and it is possible to prevent deformation of the conveyor belt due to heat, so transfer to the conveyor belt. The toner image on the image carrier can be transferred onto the transfer material by supporting the material without causing the material to float, and a good quality image can be easily prepared with the transfer material without deterioration of the image quality due to the floating of the transfer material. Can Kill.

Further, according to the fifth invention of the present application, the auxiliary heating means for supplying a predetermined amount of heat to the transfer material and the unfixed developer image on the transfer material is disposed between at least one adjacent image forming means. The fixing temperature in the fixing unit can be set low even when the amount of heat required for fixing is large, such as when the weight per unit area is large, when forming a color image, or when forming an image at high speed. In addition, it is possible to prevent the temperature rise in the apparatus and extend the life of the fixing unit.

Further, according to the sixth aspect of the present invention, the fixing means is arranged so as to be movable in the vertical direction or the transfer material conveying direction, and the transfer material guide means corresponds to the moving amount of the fixing means. Since the length in the carrying direction is variably arranged, it is possible to provide a small-sized image forming apparatus that performs good fixing even when a large amount of heat is required for fixing.

Further, according to the seventh invention of the present application, since the regulating member of the releasing agent supplying / coating means is formed in a plate shape and the contact angle with respect to the coating rotator is made variable, a large amount of heat is required for fixing. Good fixing can be performed even in the case of, and wasteful consumption of the release agent can be suppressed in the normal case.

[Brief description of drawings]

FIG. 1 is a schematic perspective view showing an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a detailed configuration of a belt and a belt holding mechanism in the apparatus shown in FIG.

FIG. 3 is a diagram for explaining the movement of a correction roller in the apparatus shown in FIG.

FIG. 4 is a diagram showing a relationship between a movement amount of a correction roller and a movement range of a belt in a normal case in the apparatus shown in FIG.

5 is a block diagram showing a schematic configuration of a control unit of a correction roller moving actuator in the apparatus of FIG.

FIG. 6 is a diagram showing a state in which the belt in the apparatus of FIG. 1 is offset.

FIG. 7 is a diagram showing a relationship between a CCD forming a belt position detecting means in the apparatus of FIG. 1 and a mark on the belt.

8A and 8B are diagrams for explaining correction control of the movement amount of the correction roller in the apparatus in FIG.

FIG. 9 is a perspective view showing a schematic configuration of a second embodiment device of the present invention.

10 is a block diagram showing an example of a control circuit of an actuator for moving a correction roller of the apparatus shown in FIG.

FIG. 11 is a cross-sectional view showing a schematic configuration of a device of Example 3 of the present invention.

FIG. 12 is a sectional view showing a schematic configuration of a drive roller of the apparatus shown in FIG.

FIG. 13 is a diagram for explaining “color shift” in a conventional example corresponding to Examples 3 and 4.

FIG. 14 is a sectional view showing a schematic configuration of a drive roller of Example 4 of the present invention.

15 is a diagram showing a method of controlling the temperature of the drive roller of the apparatus shown in FIG.

FIG. 16 is a cross-sectional view showing a schematic configuration of a device of Example 5 of the present invention.

FIG. 17 is a vertical cross-sectional view showing that the transfer material carrying unit provided in the apparatus of FIG. 16 is in a lowered state.

FIG. 18 is a flowchart showing operation control of the apparatus shown in FIG. 16;

FIG. 19 is a vertical cross-sectional view showing a schematic configuration of a transfer material conveying unit in an apparatus according to a sixth embodiment of the present invention.

20 is a flowchart showing the operation control of the apparatus shown in FIG.

FIG. 21 is a cross-sectional view showing a schematic configuration of a device according to a seventh embodiment of the present invention.

FIG. 22 is a cross-sectional view showing a schematic configuration of an apparatus of Example 8 of the present invention.

FIG. 23 is a block diagram showing a schematic configuration of a control means according to a ninth embodiment of the present invention.

FIG. 24 is a diagram showing the relationship between the amount of image information and the number of driven auxiliary heating means in the control means of FIG. 23.

FIG. 25 is a perspective view showing a schematic configuration of an apparatus according to Example 10 of the present invention.

FIG. 26 is a partially enlarged perspective view showing a transfer material guide unit of the apparatus shown in FIG. 25.

FIG. 27 is a cross-sectional view showing the position of a normal transfer material guide unit of the apparatus according to the eleventh embodiment of the present invention.

FIG. 28 is a cross-sectional view showing the position of the transfer material guide means when the amount of heat required for fixing is large in the apparatus of FIG. 27.

FIG. 29 is a view showing the position of a normal transfer material guide unit of the twelfth embodiment of the present invention.

FIG. 30 is a diagram showing the position of the transfer material guide means when the amount of heat required for fixing is large in the apparatus shown in FIG. 29.

FIG. 31 is a cross-sectional view showing the schematic configuration of an apparatus of Example 13 of the present invention.

32A is a cross-sectional view showing a state of a transfer material guide unit when a large amount of heat is required for fixing in the apparatus shown in FIG. 31;
FIG. 31B is a sectional view showing a state of a normal transfer material guide unit in the apparatus shown in FIG. 31.

FIG. 33 is a flowchart showing a control procedure of a transfer material guide unit of the apparatus shown in FIG. 31.

FIG. 34 is a perspective view showing a schematic configuration of a unit for detecting the weight per unit area of a transfer material in Example 14 of the present invention.

FIG. 35 is a flow chart showing a control procedure of the transfer material guide unit in Embodiment 14 of the present invention.

FIG. 36 is a block diagram showing a schematic configuration of a control means of a transfer material guiding means in Embodiment 15 of the present invention.

FIG. 37 is a diagram showing the relationship between the image information amount and the required developer amount in Embodiment 15 of the present invention.

FIG. 38 is a flowchart showing the control procedure of the transfer material guide unit in Embodiment 15 of the present invention.

FIG. 39 is a flowchart showing the control procedure of the transfer material guide unit in Embodiment 16 of the present invention.

FIG. 40 is a cross-sectional view showing a schematic configuration of a conventional device.

41 is a sectional view showing a schematic configuration of a fixing device of the apparatus of FIG. 40.

[Explanation of symbols]

101 belt (endless belt member) 104 driving roller (belt holding mechanism (rotatable support)) 105 tension roller (belt holding mechanism (rotatable support)) 106 correction roller (belt holding mechanism (rotatable support) (Body)) 107 driven roller (belt holding mechanism (rotatable support)) 110 actuator (moving means) 114 CCD (belt position detecting means, belt deviation speed detecting means) 120 comparison calculation circuit (belt deviation speed detecting means) 121 Memory (Belt deviation speed detecting means) 123 Driver (movement amount correcting means) 131, 131a, 131b Belt position detecting means 206 Transfer material 208 Conveying belt (transfer material conveying means) 211 Driving roller (roller) 221 Thermistor (temperature detecting means) 227 Stepping motor (driving means) P , Pb, Pc, Pd Image station 1 LBP device 11, 12, 13 Photosensitive drum 20, 21, 22 Transfer charger 26 Conveyor belt 34 Driven roller 35 Drive roller 39 Transfer material conveying means 43, 80 Cam 44 Elevating means 406a Transfer material Belt (transfer material conveying means) 407 Paper feeding cassette (transfer material supplying means) 408 Fixing device (fixing means) 410K, 410Y, 410C, 410M Auxiliary heater (auxiliary heating means) 411a, 412a Heater (heating means) 413a Release agent Tank (release agent storage container) 413c Coating roller (coating rotating body) 413d Blade (regulating member) 416 Conveying belt (transfer material guiding means) Pk, Py, Pc, Pm Image station (image forming means)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Internal reference number for FI Technical indication G03G 15/00 102 110 7369-2H 15/01 114 B 15/20 109 21/00 H04N 1/29 J 9186-5C

Claims (21)

[Claims] 1. At least one image carrying means for performing an image forming process from latent image formation to visible image formation, or a transfer material carrying means for carrying a transfer material onto which a visible image is transferred on the image carrying means. At least one of the means is an image forming apparatus having an endless belt member and a belt holding mechanism having a plurality of rotatable supports for holding the endless belt member, wherein A moving means for forcibly moving the relative position between the supports, and a belt position detecting means for detecting the position and the deviation direction of the endless belt member in the direction transverse to the moving direction of the endless belt member, The moving means alternately moves the rotatable support body to the first position and the second position according to the output of the belt position detecting means, and moves the endless belt member within a certain operating range. In an image forming apparatus that is set to forcibly reciprocate, the belt deviation speed detecting means for detecting the reciprocating speed of the endless belt member and the moving amount of the rotatable support are corrected. An image characterized by having a movement amount correcting means, wherein the movement amount correcting means is set so as to correct the movement amount of the rotatable support body according to the output of the belt deviation speed detecting means. Forming equipment. 2. An image forming device is provided with an adjusting device for adjusting an image forming timing on the image carrying device, and the image forming timing is adjusted on the basis of outputs of the belt position detecting device and the belt deviation speed detecting device. The image forming apparatus according to claim 1. 3. The belt position detecting means and the belt deviation speed detecting means are composed of at least two belt end surface detecting means arranged at both ends of the endless belt member and a time measuring means for alternately detecting the end surfaces. The image forming apparatus according to claim 1. 4. A plurality of image stations on which a visible image is formed, a transfer material conveying means which is provided adjacent to the image stations and which carries a transfer material and circulates, and the transfer material conveying means. In an image forming apparatus including two or more rollers for holding the rollers and a driving means for driving at least one of the rollers to circulate the transfer material conveying means, a roller driven by the driving means is provided. It has a temperature detection means for detecting a temperature and a speed control means for adjusting the rotation speed of the roller, and the speed control means controls the rotation speed of the roller according to the output of the temperature detection means. An image forming apparatus characterized by being set. 5. The image forming apparatus according to claim 4, wherein the driving unit is a stepping motor. 6. A plurality of image stations on which a visible image is formed, a transfer material conveying means which is provided adjacent to the image stations and carries a transfer material to circulate and move the transfer material conveying means. In an image forming apparatus including two or more rollers for holding the rollers and a driving means for driving at least one of the rollers to circulate the transfer material conveying means, a roller driven by the driving means is provided. It has a temperature detecting means for detecting the temperature and a temperature adjusting means for adjusting the temperature of the roller, and the temperature adjusting means is set so as to control the temperature of the roller according to the output of the temperature detecting means. An image forming apparatus characterized by the above. 7. A temperature-controlled at least one image carrying means for carrying out an image forming process from latent image formation to visible image formation, an endless conveyor belt in contact with the image carrying means and a plurality of rotatable members. In an image forming apparatus comprising a transfer material conveying means configured to convey a transfer material for transferring a visible image formed on the image carrying means, the conveying belt being in contact with the image carrying means. An image forming apparatus, which is installed so as to be detachable so that when the conveyor belt is stopped, the contact of the conveyor belt with the image holding means is released to make the conveyor belt non-contact. 8. The image forming apparatus according to claim 7, wherein the transfer belt is movable up and down so that the transfer belt can be brought into contact with and separated from the image carrying means. 9. At least one belt holding mechanism of the transfer material conveying means is made swingable so that the conveying belt can be brought into contact with and separated from the image carrying means, and the tension of the conveying belt is changed. The image forming apparatus according to claim 7. 10. The carrier belt is released from contact with the image carrier means for a time period in which thermal deformation due to contact of the carrier belt with the image carrier means can be prevented. The image forming apparatus according to any one of claims 7 to 9, wherein the image forming device is not in contact with the image carrying unit. 11. A transfer material supply means for accommodating the transfer material and supplying the transfer material at any time, a transfer material transfer means for transferring the transfer material supplied from the transfer material supply means, and a transfer material along a transfer direction. A plurality of image forming means arranged in parallel so as to face the transfer material conveying means and carrying unfixed developer images of different colors on the transfer material; and a transfer material conveying direction rather than the transfer material conveying means. Image formation provided with a fixing unit that has a heating unit inside and is rotatably arranged in pressure contact with each other, and that fixes the unfixed developer image on the transfer material by heating and pressurizing the image. In the image forming apparatus, an auxiliary heating means for supplying a predetermined amount of heat to the transfer material and the unfixed developer image on the transfer material is disposed between at least one adjacent image forming means. 12. A control means for controlling the driving of the auxiliary heating means, wherein the control means is set such that the larger the heat quantity required for fixing in the fixing means, the larger the heat quantity supplied by the auxiliary heating means. The image forming apparatus according to claim 11, wherein the image forming apparatus is provided. 13. The control means of the auxiliary heating means is connected to a detection means for detecting the amount of image information formed by the image forming means, and the larger the amount of image information detected by the detection means is, the fixing is performed. The image forming apparatus according to claim 12, wherein the image forming apparatus is set so that it is determined that a large amount of heat is required. 14. A transfer material supplying means for accommodating the transfer material and supplying the transfer material at any time, a transfer material conveying means for conveying the transfer material supplied from the transfer material supplying means, and a transfer material along a transfer direction. A plurality of image forming means arranged in parallel so as to face the transfer material conveying means and carrying unfixed developer images of different colors on the transfer material; and a transfer material conveying direction rather than the transfer material conveying means. A fixing unit that has a heating unit inside and is rotatably arranged in pressure contact with each other, and that fixes the unfixed developer image on the transfer material by heating and pressurizing it, and the fixing unit. In an image forming apparatus provided with a transfer material guide means for guiding the transfer material to the fixing means, which is disposed between the transfer material conveying means, the fixing means moves in the vertical direction or in the transfer material conveying direction. Arrange freely An image forming apparatus is characterized in that the transfer material guiding means is variably arranged so as to have a length in the carrying direction corresponding to a moving amount of the fixing means. 15. A driving means for the fixing means and the transfer material guide means, and a control means for the driving means, wherein the control means moves downward or forward as the amount of heat required for fixing in the fixing means increases. 15. The image forming apparatus according to claim 14, wherein the moving amount of the fixing unit and the extending amount of the transfer material guiding unit are set to be large. 16. A means for detecting the weight per unit area of the transfer material is connected to a control means, and the control means judges that the larger the weight detected by the detecting means is, the larger the amount of heat required for fixing is. The image forming apparatus according to claim 15, wherein the image forming apparatus is set as follows. 17. An image forming means for forming a multi-colored or monochromatic unfixed developer image and supporting it on a transfer material, and a heating means inside thereof, which are rotatably arranged while being in pressure contact with each other,
A fixing means for fixing the unfixed developer image on the transfer material by heating and pressurizing, and a releasing agent supplying and applying means for supplying and applying a releasing agent to the fixing means.
The releasing agent supply / applying means is arranged so as to contact the releasing agent containing container for containing the releasing agent and the fixing means, and supplies the releasing agent in the releasing agent containing container to the fixing means. An image forming apparatus having a coating rotator to be coated and a regulating member arranged so as to abut the coating rotator to regulate the amount of the release agent applied and coated. The member is formed in a plate shape and is arranged so that the contact angle with respect to the coating rotating body can be varied. Driving means for variably driving the contact angle of the regulating member, and driving by the driving means An image forming apparatus comprising: a control unit that controls the image forming apparatus. 18. The image forming apparatus according to claim 17, wherein the control unit is set to increase the contact angle of the regulating member as the amount of heat required for fixing in the fixing unit increases. 19. A unit for detecting the weight of the transfer material per unit area is connected to a control unit, and the control unit determines that the larger the weight detected by the detecting unit, the larger the amount of heat required for fixing. The image forming apparatus according to claim 18, wherein the image forming apparatus is set to make a determination. 20. The image forming apparatus according to claim 18, wherein the control unit is set so as to determine that a multicolor image requires a larger amount of heat for fixing than a monochrome image. 21. A means for detecting the amount of image information formed by the image forming means is connected to the control means, and the control means requires more fixing as the amount of image information detected by the detecting means increases. The image forming apparatus according to claim 18, wherein the image forming apparatus is set so as to determine that the amount of heat is large.