JPH08248828A - Printer - Google Patents

Abstract

PURPOSE: To prevent the damage and short, life of a belt, a roller, etc., and the enlargement of a device scale, without requiring a complicated circuit by making the distance from a slidable contact part for performing the heat exchange of a belt to a developing unit longer than the length of the slidable contact part. CONSTITUTION: When the belt 1 is carried, an electrostatic latent image is formed on the belt 1 by a writing head 17 and actualized by the developing unit 18. After that, the belt 1 is heated to raise temperature with the heat of the belt 1 returned to a heating roller 11, in the slidable contact part 15. When the belt 1 passes through a transfer fixing part, the actualized image is transferred and fixed to a paper sheet 20 by the heating roller 11 and a pressure roller 16. The belt 1 heated by the heating roller 11 is carried to the slidable- contact part 15, brought into contact with the belt 1 during movement from the developing unit 18, to be cooled by the heat exchange and further, passed through a pressing roller 14, to be cooled by air, while passing in the air on a long path.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer, and more particularly, to a latent image formed on a dielectric belt, a toner image formed on the belt by a developing device, and the toner image formed on the belt by heat and pressure. The present invention relates to a printer that simultaneously transfers and fixes a recording medium.

[0002]

2. Description of the Related Art In recent years, a printer has been developed in which a toner image is formed on a dielectric belt by a developing device, and the toner image on the belt is simultaneously transferred and fixed on a recording medium by heat and pressure. For example, Japanese Patent Laid-Open No. 4-298777 discloses an endless belt as a transfer member in a printing system. The endless belt moves between an unheated position for picking up toner powder and a heated position where the toner powder is melted and then transferred to a sheet to form a print.

The endless belt is less likely to carry heat, and the portions of the belt that move in the opposite direction between the heated position and the non-heated position are kept close to each other. There is therefore a heat exchange there, which reduces the energy required to bring each part of the belt into thermal equilibrium with that position at each position, reducing the energy loss due to the thermal cycling of the belt. .

Further, as a general method for preventing the meandering of the belt in such a printer, the meandering range is defined 2.
It is known to control the belt so that the belt reciprocates between the sensors by two sensors.

For example, in Japanese Unexamined Patent Publication (Kokai) No. 5-238583, infinite reciprocation within a predetermined range is achieved by displacing the endless film conveying member in the lateral movement motion of the endless film in the widthwise conveying process. The film shift control means for exercising, the means for detecting the shift speed of the film in the width direction, and the means for detecting the shift time during a predetermined distance in the width direction of the film, and the detection information of the detection means. According to the detection information of the detection means, in order to prevent wear at the same place and to prolong the life, the endless film conveyance member has a control means for changing the displacement amount of the endless film transport member. An apparatus for controlling the infinite reciprocating movement range in the width direction of the film is described.

[0006]

However, in a printer in which a latent image and a toner image are formed on one belt and the two images are transferred and fixed to a recording medium by heat and pressure, the following is performed. I have a problem.

That is, the belt, which has become high in temperature in the transfer / fixing section, has a problem that the temperature of the developing device is raised when passing through the developing device to melt and fix the toner in the developing device. Therefore, the temperature of the belt passing through the developing device must be lowered.

The thermal energy carried by the belt from the high temperature part to the low temperature part increases in proportion to the running speed of the belt. As a result, the device has poor thermal efficiency. In order to solve this problem, in the above-mentioned Japanese Patent Laid-Open No. 4-298777, heat exchange is performed by rubbing a belt traveling from a high temperature portion to a low temperature portion and a belt traveling from a low temperature portion to a high temperature portion to exchange heat. The heat energy transferred from the low temperature part to the low temperature part is reduced. This heat exchange is more complete when the belt's lap section is longer.

By the way, in order to keep the temperature from the high temperature portion after passing through the rubbing to a desired temperature (maximum storage temperature of powder toner) or lower without using a special cooling mechanism, the belt rubbing is performed. The fitting section must be long.
However, by lengthening the section of fitting,
The following issues arise. That is: a) Belt wear increases and belt life shortens.

B) The device becomes large. c) The load on the belt drive motor increases. Further, the dielectric layer formed on the flexible conductive belt is more susceptible to mechanical stress than the dielectric layer formed on the hard drum, and the life per unit length is shortened. Will end up. Therefore, the circumference of the belt must be increased in order to prolong the service life.

However, the above-mentioned JP-A-4-29877.
In the structure of the system described in Japanese Patent Publication No. 7, the shape of the entire system becomes large. On the other hand, in a printer in which the belt is always in contact with the heating roller, the belt must always be run to ensure the uniformity of the belt even during non-printing. However, it is generally known that when the belt is run, the belt is biased in one direction, and the end of the belt hits the flange of the roller or the like and is damaged.

As a general method of preventing such belt meandering, a control as shown in FIG. 18 is known. That is, the rollers 2 and 3 around which the belt 1 is wound
Between the meandering correction roller 4 and two sensors 5 and 6 that determine the range of meandering, the belt 1 controls the belt 1 so as to reciprocate between the sensors. It is designed so that it does not come off between 6 and 6.

However, if the two sensors are in a wide range from the beginning, after the latent image is formed on the dielectric belt by the writing head, the belt meanders until it reaches the transfer / fixing section, and the belt widthwise with respect to the paper. The relative position of the image transferred to the recording paper with respect to the paper is displaced due to the shift of the position of. Further, since the writing operation is performed while the belt moves in the width direction, a latent image that is obliquely distorted is formed.

Further, if the two sensors are in a narrow range from the beginning, the reciprocating movement of the belt becomes frequent even during non-printing, and the durability of the meandering preventing mechanism and the belt and the like becomes short.

Further, in the above-mentioned JP-A-5-238583, the forward movement speed and the backward movement speed when the belt reciprocates between the two sensors are deviated by a predetermined distance between the two sensors. By the method of obtaining by detecting time, the average speed of the belt moving between the two sensors can be obtained by dividing the distance between two known sensors by the time. When it is desired to move the belt a desired distance, the reciprocating movement range is changed by displacing the meandering correction roller for a time obtained by dividing the desired moving distance by the forward moving speed and the backward moving speed. I'm taking the way.

However, this method has the following problems. That is, it is difficult to directly detect the deviation speed of the belt, and the position information obtained from the position sensor is differentiated with respect to time to calculate the speed, which requires a complicated circuit. In addition, the detected speed is merely an average speed over a predetermined distance, and does not represent the speed at each place in the meantime. Therefore, it was difficult to accurately set the reciprocating range at a certain place to the desired range based on this average speed.

The present invention has been made in order to solve the above problems, and does not damage a belt, a roller, or the like, shortens the service life thereof, does not require a complicated circuit, and does not increase the size of the printer. The purpose is to provide.

[0018]

That is, the present invention is directed to an endless dielectric belt that is conveyed, a writing head that forms an electrostatic latent image on the dielectric belt, and a toner image on the electrostatic latent image. Developing means for forming a toner image, a transfer means for transferring the toner image onto a recording medium by at least heat, a dielectric belt heated to a high temperature by the transfer means, and a dielectric belt from the developing means to the transfer means. From the rubbing part to the developing means. The rubbing part for rubbing the heat exchange part with each other to perform heat exchange, and the length of the rubbing section by the rubbing part is L1. If the path length of the belt in the section is L2, L2
Is longer than L1.

According to the present invention, the printer further comprises a plurality of rollers at a position where the dielectric belt comes into contact with the belt in a section from the rubbing means to the developing means. It is characterized in that it is folded back with a length shorter than L1 to form a belt path in a compact space.

Further, according to the present invention, there is provided an endless dielectric belt to be conveyed, a writing head for forming an electrostatic latent image on the dielectric belt, and a developing means for forming a toner image on the electrostatic latent image. , Heat transfer by transferring transfer means for transferring the toner image onto a recording medium by at least heat, a dielectric belt heated to a high temperature by the transfer means, and a dielectric belt from the developing means to the transfer means. And a meandering correction roller that corrects the meandering of the dielectric belt, a driving unit that drives the meandering correction roller, an electrostatic latent image formed by the writing head, and a toner image formed by the developing unit. The electrostatic latent image is formed by the writing head and the toner image is formed by the developing unit more than the period in which the formation and the transfer of the toner image are not all performed. Control means for controlling the driving means so that the dielectric belt moves within a narrower area in the width direction of the dielectric belt during any one of the transfer of the toner image by the transfer means. And a plurality of sensors for detecting the meandering range of the dielectric belt and inputting the detection result to the control means.

[0021]

In the printer of the present invention, an electrostatic latent image is formed on the dielectric belt passing through the writing head. Next, when the toner image is formed on the dielectric belt when passing through the developing means, the heat of the belt returned from the transfer means when passing through the rubbing portion where the dielectric belt is rubbed to perform heat exchange. It is heated by and the temperature rises. Then, the belt on which the toner image is placed is nipped together with the recording medium when passing through the transfer means, and the toner image is transferred to the recording medium. Then, the belt heated by the transfer means enters the rubbing section, contacts the belt moving from the developing means to the transfer means, is heat-exchanged, and is cooled. Next, the belt exiting the rubbing section is cooled by the air while passing through the air in a long path, and when passing through the developing means, the belt is lowered to a temperature at which it does not affect the toner completely and is lowered to a desired temperature. . After that, the write head is passed in this state, and the above operation is repeated again.

In the printer of the present invention, the printer is further provided with a plurality of rollers at positions where the dielectric belt comes into contact with the belt in a section from the exit of the rubbing section to the entry of the developing means. To be With these plural rollers, the belt can be folded back with a length shorter than L1 to form a belt path in a compact space.

Further, in the printer of the present invention, the electrostatic latent image is formed by the writing head on the conveyed endless dielectric belt. Then, when a toner image is formed on the electrostatic latent image by the developing device, the toner image is transferred to the recording medium by the transfer device by at least heat. The dielectric belt heated to a high temperature by the transfer means is rubbed with the dielectric belt from the developing means to the transfer means at the rubbing portion to perform heat exchange. On the other hand, the meandering correction roller driven by the driving means corrects the meandering of the dielectric belt. Then, the driving unit is operated by the writing head rather than a period in which the electrostatic latent image is not formed by the writing head, the toner image is formed by the developing unit, and the toner image is not transferred by the transfer unit. A narrower range in the width direction of the dielectric belt during a period in which one of the formation of the electrostatic latent image, the formation of the toner image by the developing unit, and the transfer of the toner image by the transfer unit is performed. Is controlled by the control means so that the dielectric belt moves. Detection results are input to the control means from a plurality of sensors that detect the meandering range of the dielectric belt.

[0024]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a schematic configuration of a printer according to a first embodiment of the present invention. A dielectric endless belt 1 is stretched between a heating roller 11 and a non-heating roller 12. The belt 1 is conveyed in the direction of the arrow in the figure, and a rubbing portion 15 as a heat exchange portion is formed between the pressure rollers 13 and 14 provided near the heating roller 11 and the non-heating roller 12. There is.

On the heating roller 11, there is provided a pressure roller 16 which constitutes a transfer and fixing section together with the heating roller 11. On the other hand, around the non-heating roller 12, the writing head 17 for forming a latent image on the belt 1.
And a developing device 18 that attaches toner to the latent image to visualize the latent image. The non-heating roller 12, the writing head 17, and the developing device 18 constitute an image forming unit.

Here, in the printer having the above-mentioned configuration, a model of fitting will be described. The conditions of the first model are shown below. 1) Air temperature inside the machine 40 ° C. 2) Belt peripheral speed of 250 mm / sec. 3) Belt material is polyimide i) Heat capacity per unit volume of polyimide is 1.5
4 * 10.6 J / ° C / (m * m * m) ii) As thermal resistance per unit length of polyimide 6.15 ° C / W * m iii) As thermal resistance at contact between polyimide and polyimide 0 0.0074 ℃ / w / (m * m) …… Experimental value iv) 0.164 ℃ / W / (m * m) …… Experimental value v) Belt as thermal resistance in contact between air and polyimide Thickness is 75 microns 4) Toner has a melting temperature of 120 ° C and a maximum storage temperature of 5
0 ° C 5) Belt temperature 200 ° C at point A in the figure 6) Belt temperature 50 ° C at point C in the figure.

FIG. 2 is a diagram showing the temperature distribution of the belt when the length of the fitting portion 15 is 300 mm in the first model. Here, before heating means the temperature distribution of the belt conveyed from the non-heating roller 12 side to the heating roller 11, and after heating means the temperature distribution of the belt conveyed from the heating roller 11 side to the non-heating roller 12. ing.

Further, FIG. 3 shows A in FIG. 1 in the case where the length of the fitting portion in FIG. 2 is changed by 50 mm and from 100 mm to 600 mm in 100 mm steps.
It is a figure showing the temperature of the point, B point, C point, and D point.

Further, FIG. 4 shows that the polyimide belt 1 heated to 100 ° C. is 250 mm in air at 40 ° C.
/ Sec. It is a figure showing the belt temperature with respect to the passage distance when passing at the speed of.

FIG. 5 is a view in which FIG. 4 is made easier to see.
FIG. 4 is a diagram showing a belt traveling distance required for cooling to 50 ° C. with a point P (50 ° C., 4215 mm) in FIG.

By the way, what is noticed in the printer having the configuration shown in FIG. 1 is the temperature at the point D and the temperature at the point B. What is meant by (temperature at point A-temperature at point D) is
The heating roller 11 represents the thermal energy applied to the belt 1, that is, the temperature at which the belt 1 is heated. The meaning of (temperature at point B-temperature at point C) represents the thermal energy taken by the non-heating roller 12 from the belt 1, that is, the temperature at which the belt 1 is cooled.

As shown in FIG. 3, these temperature differences increase as the length of the fitting portion 15 decreases. next,
The length of the rubbing portion 15 which does not require the non-heating roller 12 to cool the belt 1 is obtained from FIG.

This means that (temperature at point B-temperature at point C) is 0
It means the length of the rubbed part 15 which becomes ℃, about 600mm
Becomes At this time, (temperature at point A-temperature at point D) is about 9
° C. This temperature does not decrease even if the contact of the belt 1 is made longer than this. This is because the heat radiated from the belt 1 to the air is equivalent to the heat roller 11
Is being replenished.

Therefore, the length of the lapped portion 15 is made as short as possible within a range in which the temperature difference between the points A and D can be tolerated.
For example, if the length of the rubbed portion 15 is about 300 mm, (temperature at point A-temperature at point D) is about 12 ° C.,
(Temperature at point B-temperature at point C) is about 4 ° C. Therefore, normally, the non-heating roller 12 should cool the belt 1 by about 4 ° C.

In the present invention, this cooling is performed by the non-heating roller 12
Instead of the above, the belt 1 is cooled by passing it through a long path in the air. The length of the path required is about 1 m, as shown in FIG.

That is, in the case of only the rubbed portion, the length of the rubbed portion 15 needs to be 600 mm, whereas when the length of the rubbed portion 15 is 300 mm, the length of the non-rubbed portion is It means that at least about 1m is required.

Since the non-rubbed portion of about 1 m can be made compact as in the third and fourth embodiments described later, the entire apparatus can be made small, and the total belt length is long. Therefore, the life can be extended.

Next, the operation of the printer thus configured will be described. When the rollers and the like are driven by a drive system (not shown), the belt 1 is conveyed in the direction of the arrow shown in the drawing, and the writing head 17 first forms an electrostatic latent image on the belt 1. Then, the developing device 18 visualizes the electrostatic latent image on the belt 1 by attaching toner to the toner. After that, when passing through the lapping section 15, the belt 1 is heated by the heat of the belt 1 returned from the heating roller 11,
The temperature rises.

Next, when the belt 1 to which the toner image is attached passes through the transfer / fixing portion, it is nipped together with the paper 20 as a recording medium by the heating roller 11 and the pressure roller 16 to form the toner image on the paper 20. At the same time, it is transferred and fixed. Then, the belt 1 heated by the heating roller 11
Is conveyed again to the lapping unit 15, contacts the belt 1 which is moving from the developing device 18 to the heating roller 11, and is heat-exchanged and cooled. However, at this time, the belt temperature is not yet completely lowered.

In this way, the belt 1 exiting the rubbing section 15, that is, passing through the pressing roller 14, is cooled by air while passing through the air in a long path. As a result, when the toner passes through the developing device 18, the temperature drops to a temperature at which the toner is not completely affected and then drops to a desired temperature.

In this way, the above operation is repeated again. Next, a second embodiment of the present invention will be described. In the second embodiment, the temperature at the point A, which is the condition of the first model in the above-mentioned first embodiment, is 200 ° C.
That was 150 ° C.

FIG. 6 corresponds to FIG. 3 in the first embodiment and is a graph showing the temperature at both ends of the belt with respect to the length of the lapped portion 15 when the point A is 150 ° C. The length of the rubbing portion 15 that does not require the non-heating roller 12 to cool the belt 1 can be obtained from FIG. This means the length of the rubbed portion 15 where (temperature at point B-temperature at point C) is 0 ° C., and the value is about 500 mm. At this time (A
The temperature of the point-the temperature of the point D) is about 6.82 ° C.

Within a range in which the temperature difference between points A and D is allowable,
The length of the lapping section 15 is made as short as possible. For example,
Assuming that the length of the rubbed portion 15 is about 300 mm, (temperature at point A-temperature at point D) is about 8.3 ° C, and (temperature at point B-temperature at point C) is about 2.6 ° C. Is. Therefore, normally, the non-heating roller 12 should cool the belt 1 by about 2.6 ° C.

In the second embodiment, the length of the path required for cooling the belt 1 is about 4 as shown in FIG.
It becomes 90 mm. That is, in the case of only rubbing, the length of the rubbing portion 15 needs to be 500 mm, while
When the length of the rubbed portion 15 is 300 mm, the length of the non-rubbed portion needs to be at least about 490 mm.

Since this non-rubbed portion of about 490 mm can be made compact as in the third and fourth embodiments described later, the entire apparatus can be made small, and the total belt length is long. Therefore, the life can be extended.

Next, a third embodiment will be described.
In the embodiments described below, the same components are designated by the same reference numerals, and the description thereof will be omitted. If the belt having the length of the value obtained by the above-described first embodiment is extended as it is, there is a possibility that the device becomes large. Therefore, in this third embodiment, for example,
As shown in FIGS. 7 and 8, a plurality of rollers are used to fold the non-rubbed portion of the belt 1 into a bellows shape to make it compact.

That is, in FIG. 7, the heating roller 11
A bellows portion 21 ₁ that folds the belt 1 after being heated by a plurality of rollers into a bellows shape is provided between the pressing roller 14 and the non-heating roller 12. In this case, the belt ₁ in the bellows portion 21 ₁ is conveyed in a direction substantially parallel to the rubbing portion 15.

Reference numerals 22 and 23 are cleaners and erasers for removing the toner and charges remaining on the belt 1. Further, in FIG. 8, the pressing roller 14 and the non-heating roller 1
The belt 1 in the bellows portion 21 ₂ provided between the two is conveyed in a direction intersecting the rubbing portion 15.

The form of these bellows parts 21 ₁ and 21 ₂ is
It can be selected according to the configuration of the entire apparatus. In this way, the bellows portions 21 ₁ and 21 ₂ are attached to the non-rubbed portion of the belt 1.
The size of the entire apparatus can be reduced by providing the.

Next, a fourth embodiment will be described. In the fourth embodiment, the non-rubbed portion of the belt having the length obtained by the second embodiment described above is spirally folded to be compact.

As shown in FIG. 9, a spiral portion 24 for spirally folding the belt 1 after being heated by the heating roller 11 by a plurality of rollers is provided between the pressing roller 14 and the non-heating roller 12. There is.

As described above, the size of the entire apparatus can be reduced by providing the spiral portion 24 in the non-rubbed portion of the belt 1 so as to make it compact. Next explained is the fifth embodiment of the invention.

In the fifth embodiment, two meandering range detecting sensors are used in the construction of the first embodiment described above. This meandering range detection sensor may be either a transmissive type or a reflective type.

The transmissive sensor is composed of a light emitting element, a light receiving element, and a space through which an object to be detected can enter and exit. Light emitted from the light emitting element goes straight and is on the opposite side through a space through which the object to be detected can enter and exit. It is arranged so as to reach the light receiving element.
Therefore, when there is no detection object between the light emitting element and the light receiving element, the light receiving element is in a state of receiving light, while when there is a detection object between the light emitting element and the light receiving element, the light receiving element does not receive light. It becomes a state.

On the other hand, the reflection type sensor is composed of a light emitting element, a light receiving element and a space through which an object to be detected can enter and exit, and the light emitted from the light emitting element is an object to be detected in a space where the object can enter and exit. It is arranged so that it is reflected and the reflected light reaches the light receiving element. Therefore, if there is an object to be detected in the space, the light receiving element is in a state of receiving light, and if not, the light receiving element is in a state of not receiving light.

Here, an example in which a transmissive sensor is used as the meandering range detecting sensor will be described with reference to FIG. At least one of the two sensors (the sensor 26 in this example) is an analog output sensor, and outputs an analog signal corresponding to the position when the belt 1 blocks the analog sensor. .

FIG. 10A shows three states depending on the difference in the relationship between the sensor 26 and the belt 1, and the state of the analog output value of the sensor 26 in each state. When a narrow range reciprocating movement command is received, the belt 1 is moved to the sensor side of this analog output, and this analog signal is compared at two levels. Here, as shown in FIG. 10 (c), when the analog signal is between these two levels, the output is held, and when the analog signal is higher than the two levels, the output is set to a high level. Next to
Further, when the analog signal is lower than the two levels, the output of the Schmitt trigger circuit, whose output is reset and becomes low level, is passed through, and the state of the meandering correction roller 4 is controlled by the output state of the Schmitt trigger circuit.

FIG. 11 is a block diagram showing an example of the control means of the meandering correction roller 4. In the figure,
A signal from the analog output sensor 26 is input to the R (reset) terminal of the flip-flop 28 via the Schmitt trigger circuit 27. A signal from an ON / OFF output sensor 29 is supplied to the S (set) terminal of the flip-flop 28. The Q output of the flip-flop 28 is supplied to one input terminal of the AND circuit 31. The other input terminal of the AND circuit 31 is connected to the knot circuit 3
A range designation signal is supplied via 2.

The output of the Schmitt trigger circuit 27 is also supplied to one input terminal of the AND circuit 33 via the knot circuit 30. The range designation signal is supplied to the other input terminal of the AND circuit 33.

Further, the output of the knot circuit 30 is supplied to the S terminal of the flip-flop 34. The output of the knot circuit 32 is supplied to the R terminal of the flip-flop 34, and the transition end signal is output from the Q terminal.

The outputs of the AND circuits 31 and 33 are supplied to the OR circuit 35. Then, the output of the OR circuit 35 is supplied to the meandering correction roller 4 via the meandering correction roller drive circuit 36.

The meandering correction roller drive circuit 36 operates to set the meandering correction roller 4 to the state X ₂ when the input signal is at a high level, as shown in FIG. Similarly, when the input signal of the meandering correction roller drive circuit 36 is at the low level, the meandering correction roller 4 is set to the state X ₁
Works as if set to. Specifically, the meandering correction roller drive circuit 36 is composed of a solenoid driver, and the meandering correction roller 4 is held in the state X ₂ by a spring (not shown). Then, a solenoid (not shown) is pulled to set the state to X ₁ .

In the fifth embodiment, the positions of the sensors 26 and 29 are fixed. In such a structure, the range specifying signal is at the low level in the case of a wide range of reciprocating movement operation. Therefore, as the input signal of the meandering correction roller drive circuit 36, the output signal of the flip-flop 28 is selected, and when the belt 1 hits the sensor 29, the meandering correction roller 4 causes the belt 1 to move to the sensor 26 side. Flip to.

When the belt 1 hits the sensor 26, the meandering correction roller 4 is reversed, and the belt 1 detects the sensor 29.
Will move to the side of. In such a state,
When the range designation signal becomes high level, the output of the Schmitt trigger circuit 27 is selected as the input signal of the meandering correction roller drive circuit 36. Therefore, the operation of the meandering correction roller 4 is controlled only by the sensor 26.

The state of the meandering correction roller 4 under the control based on the output of the sensor 26 at this time is shown in FIG. Further, when the belt 1 is applied to the sensor 26 for the first time after the range designation signal becomes high level, the transition end signal becomes high level for the first time. Therefore, the fact that the belt 1 has completed moving to the vicinity of the sensor 26 is notified. That is, a range designation signal is output from a controller (not shown) that controls the entire printer, and a transition end signal is input to the controller that controls the entire printer.

Next explained is the sixth embodiment of the invention. The sixth embodiment has the same structure as the second embodiment, as shown in FIG. 13 and FIG.
It uses one sensor. Then, as shown in FIG. 13, the position of at least one sensor (sensor 29 in this case) of the two sensors is variable so that the distance between the two sensors can be widened or narrowed. It was made possible.

FIG. 14 is a block diagram showing an example of the control means of the meandering correction roller 4. In the figure,
The outputs of the sensors 26 and 29 are supplied to the R terminal and the S terminal of the flip-flop 28, respectively. Then, the Q output of the flip-flop 28 is supplied to the meandering correction roller 4 via the meandering correction roller drive circuit 36.

The flip-flop 34 has an S terminal for the output of the sensor 26 and an R terminal for the knot circuit 32.
A range movement signal is supplied via. In addition, the Q output serves as a transition end signal. Further, the range designation signal is supplied to the sensor moving actuator 38 via the driver 37.

In such a structure, when the range designation signal is at the low level, that is, when the reciprocating movement operation instruction is in a wide range, the sensor moving actuator 38 causes the sensor 2 to move.
In order to displace 9 to a position far from the sensor 26, the belt 1 performs reciprocating movement over a wide range.

On the other hand, when the range designation signal becomes high level, the sensor moving actuator 38 displaces the sensor 29 closer to the sensor 26, so that the belt 1 reciprocates within a narrow range.

Further, the transition end signal is output when the belt 1 hits the sensor 26 for the first time after the range designation signal becomes high level. Next, a seventh embodiment of the present invention will be described.

In the seventh embodiment, as shown in FIG. 15, three sensors are used. In this case, one sensor 26 is provided on the left side in the belt conveying direction X, and two sensors (sensor 29 and sensor 39) are provided on the right side in the belt conveying direction X. One of the sensors on the right side in the belt conveyance direction X is a wide range sensor (29).
The other is used as a narrow range sensor (39).

The number of sensors may be two on the left side in the belt conveyance direction X and one on the right side in the belt conveyance direction X. FIG. 16 is a block diagram showing an example of the control means of the meandering correction roller 4 according to the seventh embodiment.

The AND circuit 31 has a narrow range of sensors 3
9 is supplied with the range designating signal, and the AND circuit 33 is supplied with the range designating signal via the output of the sensor 29 in a wide range and the knot circuit 32. AND circuits 31 and 33
Is output to the OR circuit 35, and the output of the OR circuit 35 is input to the S terminal of the flip-flop 28.

At the R terminal of the flip-flop 28,
The output of the sensor 26 is input. Then, the Q output is supplied to the meandering correction roller 4 via the meandering correction roller drive circuit 36.

The output of the sensor 26 is supplied to the S terminal and the output of the knot circuit 32 is supplied to the R terminal of the flip-flop 34. The Q output is the transition end signal.

In such a structure, the sensor 29 and the sensor 26 are selected when the range designation signal is at the low level. Then, the reciprocating movement of the belt 1 is performed between the sensor 26 and the sensor 29.

When the range designation signal becomes high level, the sensor 39 and the sensor 26 are selected. in this case,
The reciprocating movement of the belt 1 is performed between the sensor 39 and the sensor 26.

The transition end signal is output when the belt 1 is applied to the sensor 26 after the range designation signal becomes high level. Next, an eighth embodiment of the invention will be described.

FIG. 17 is a block diagram of a printer according to the eighth embodiment. In the figure, from the controller 40 for the entire printing, the belt peripheral speed at the time of printing, the peripheral speed higher than the belt peripheral speed at the time of printing, the peripheral speed lower than the belt peripheral speed at the time of printing, stop, 4 The types of states are designated to the belt drive motor speed control circuit and the motor 41 which can be set by two signal lines of the speed designation signal. Further, a range designation signal and a transition completion signal are supplied between the controller 40 and the meandering prevention device 42 of the entire print.

If there is no print request, the controller 40 for the entire print causes the belt drive motor speed control circuit and the motor 41 to perform the reciprocating movement of the belt at the same time. , The main motor driving the belt is driven at a low speed.

When a print request is issued from the host computer 43 to the controller 40 of the printer as a whole, the range designation signal goes high while the range of the reciprocating movement is changed from a wide range to a narrow range. After that, until the transition end signal becomes high level, the speed of the main motor is switched to a speed faster than the speed at the time of printing to perform the transition promptly.

Then, after waiting for the transition end signal to become high level, the main motor is driven at the printing speed to notify the host computer 43 side of the printable state,
Start printing.

In the eighth embodiment, the three speeds described above, that is, the belt peripheral speed during printing, the peripheral speed higher than the belt peripheral speed during printing, and the belt peripheral speed during printing are used. Of the lower peripheral speeds, the highest speed may be the one in which the maximum voltage is applied to the main motor and the speed control is not performed.

The above description is based on the embodiments, but the present invention includes the following inventions in this specification. (1) An endless dielectric belt that is conveyed, a writing head that forms an electrostatic latent image on the dielectric belt, and a developing unit that forms a toner image on the electrostatic latent image.
Transfer means for transferring the toner image onto a recording medium by at least heat, a dielectric belt heated to a high temperature by the transfer means, and a dielectric belt from the developing means to the transfer means are rubbed together for heat exchange. Having a rubbing part to be performed,
Let L1 be the length of the section to be rubbed by the rubbed section, and let L2 be the length of the belt path in the section from the dielectric belt exiting the rubbed section to entering the developing means. Is longer than L1.

The embodiment relating to the present invention is, for example, the first,
The second, third and fourth embodiments correspond. (2) In the printer according to (1) above, a plurality of rollers are further provided at a position where the dielectric belt comes into contact with the belt in a section from the rubbing section to the developing means.
2. The printer according to claim 1, wherein the plurality of rollers are folded back with a length shorter than the length L1 to form a belt path in a compact space.

The embodiments relating to the present invention correspond to, for example, the third and fourth embodiments. (3) An endless dielectric belt that is conveyed, a writing head that forms an electrostatic latent image on the dielectric belt, and a developing unit that forms a toner image on the electrostatic latent image.
Transfer means for transferring the toner image onto a recording medium by at least heat, a dielectric belt heated to a high temperature by the transfer means, and a dielectric belt from the developing means to the transfer means are rubbed together for heat exchange. A rubbing section to be performed, a meandering correction roller for correcting the meandering of the dielectric belt, a driving means for driving the meandering correction roller, an electrostatic latent image formation by the writing head, and a toner image formation by the developing means. Of the electrostatic latent image formed by the writing head, the toner image formed by the developing unit, and the toner image transferred by the transfer unit than the period in which the transfer unit does not transfer the toner image. A control means for controlling the driving means so that the dielectric belt moves in a narrower range with respect to the width direction of the dielectric belt during a period in which any one of them is performed; Printer, characterized in that it comprises a plurality of sensors for inputting the detection result to the detected said controlling means meandering scope of the dielectric belt.

The embodiment relating to the present invention is, for example, the fifth,
The sixth, seventh and eighth embodiments correspond. (4) The printer according to (3), wherein the plurality of sensors are sensors that detect the positions of both ends of the dielectric belt.

The embodiment relating to the present invention is, for example, the fifth,
The sixth, seventh and eighth embodiments correspond. (5) The printer according to (3) or (4) above further includes a Schmitt trigger circuit, and at least one of the plurality of sensors that detects the position of one end of the dielectric belt is the end of the recording medium. It is composed of an analog output sensor that outputs part position information as an analog value.The analog output value of the analog output sensor is converted to a digital value via the Schmitt trigger circuit and input to the control means, and the static electricity generated by the writing head During a period in which the formation of the electric latent image, the formation of the toner image by the developing unit, and the transfer of the toner image by the transfer unit are not all performed, the detection results of the plurality of sensors are input to the control unit, and the write head is input. A period in which any one of the formation of an electrostatic latent image by means of, the formation of a toner image by the developing means, and the transfer of the toner image by the transfer means is being performed. In the printer according to (3) or (4), the detection result of only the analog output sensor is input to the control means.

The embodiment relating to the present invention corresponds to, for example, the fifth embodiment. (6) In the printer according to (3) or (4) above, further, at least one of the plurality of sensors for detecting the position of one end of the dielectric belt is moved in the width direction of the dielectric belt. And a driver for driving the moving actuator. The electrostatic latent image is formed by the write head, the toner image is formed by the developing unit, and the toner image is transferred by the transfer unit. The dielectric belt is in a period in which one of the formation of the electrostatic latent image by the writing head, the formation of the toner image by the developing unit, and the transfer of the toner image by the transfer unit is performed, rather than the non-existing period. The control means controls the moving actuator so that a sensor for detecting the position of one end of the moving body approaches the dielectric belt. The printer according to (3) or (4).

The embodiment relating to the present invention corresponds to, for example, the sixth embodiment. (7) Among the plurality of sensors, there are a plurality of sensors for detecting at least one end position of the dielectric belt, and the plurality of sensors are arranged with their positions displaced in the width direction of the dielectric belt. While the electrostatic latent image is formed by the write head, the toner image is formed by the developing unit, and the toner image is not transferred by the transfer unit, the detection result of the sensor farther from the dielectric belt is displayed. Input to the control means, the dielectric belt during a period in which one of the formation of an electrostatic latent image by the write head, the formation of a toner image by the developing means, and the transfer of the toner image by the transfer means is performed. The detection result of the sensor closer to is input to the control means. (3)
Alternatively, the printer according to (4).

The seventh embodiment corresponds to the embodiment relating to the present invention. (8) The printer according to any one of (3) to (7), further includes a controller for the entire printer, a belt drive motor that drives the dielectric belt in the transport direction, and a drive of the belt drive motor. The controller of the whole printer has a speed control means for controlling the speed, and gives the control means a range designating signal designating a range in which the dielectric belt is moved in the width direction of the dielectric belt, and the control means Indicates to the controller a transition end signal indicating that the movement of the moving range of the dielectric belt has ended within the range designated by the controller, and the controller designates a narrow range in the range designation signal and Indicates that the peripheral speed of the dielectric belt is higher than the printing speed, the speed designation signal is sent to the speed control means. When the range designating signal designates a narrow range and the transition end signal indicates the end of the transition, the controller causes the speed control means to set the peripheral speed of the dielectric belt to the printing speed. To the speed control means so that the peripheral speed of the dielectric belt is slower than the printing speed when the range designating signal designates a wide range. (3) to (7), characterized in that
The printer according to any one of 1.

The eighth embodiment corresponds to the embodiment relating to the present invention. (9) When the meandering prevention device is performing a belt reciprocating movement in a narrow range, the peripheral speed of the dielectric belt is set to a printing speed, and the meandering preventing device causes the belt reciprocating movement in a wide range to a narrow belt. While shifting to reciprocating movement, the peripheral speed of the dielectric belt is made faster than the speed at the time of printing, and the meandering prevention device shifts from narrow belt reciprocating movement to wide belt reciprocating movement. A belt drive circuit is further provided for controlling the peripheral speed of the dielectric belt to be slower than the speed at the time of printing when the belt reciprocates in a wide range over a wide range. The printer according to 3).

The eighth embodiment corresponds to the embodiment relating to the present invention. According to the configuration of (1), the belt passes through the compact space and is cooled by the air. Further, the non-rubbed portion, which is longer than the rubbed portion, is formed so that the belt can be made longer, so that the life of the belt can be extended.

Further, according to the above configuration (2), the belt is folded by using a plurality of rollers to form the bellows portion, and the belt is cooled by the bellows portion, so that the apparatus can be made compact. it can. Further, since the belt of the bellows portion has a long length in contact with air, it has an effect of natural cooling, and the heat of the transfer fixing portion applied to the belt is not transmitted to the developing device.

According to the above configurations (3) to (8), it is possible to prevent the belt from meandering in one direction and finally riding on the flange of the roller or the like to damage the belt. In the meantime, by reducing the meandering width, it is possible to reduce the distortion of the surface image and reduce the variation in the printing position on the paper. Further, since the number of belt reciprocations per unit time is reduced during non-printing, the durability of the mechanism for driving the correction roller can be extended.

According to the above configuration (9), the shift to the printable state can be performed more quickly, and the number of belt reciprocating movements during non-printing per unit time can be further reduced. The life of the correction roller drive mechanism and the belt can be further extended.

[0098]

As described above, according to the present invention, it is possible to provide a printer which does not damage a belt, a roller or the like and shortens the life thereof, does not require a complicated circuit, and does not increase the size of the apparatus. You can

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a first embodiment of a printer according to the present invention.

FIG. 2 is a characteristic diagram showing a temperature distribution in the printer having the configuration shown in FIG. 1 when a fitting length of a fitting portion is 300 mm.

FIG. 3 is a characteristic diagram showing both-end temperatures with respect to a fitting length when point A in FIG. 1 is 200 ° C.

FIG. 4 shows that the belt of FIG. 1 is 250 mm / in air at 40 ° C.
sec. FIG. 6 is a characteristic diagram showing the belt temperature with respect to the passing distance when passing at a speed of.

FIG. 5 is a graph in which the point P in the characteristic diagram of FIG.
It is a characteristic view showing the belt running distance required for cooling to 0 ° C.

FIG. 6 shows a point A of FIG. 1 of 150 ° C. in the second embodiment.
FIG. 6 is a characteristic diagram showing a temperature at both ends with respect to a fitting length in the case of.

FIG. 7 is a diagram showing a configuration example of a printer according to a third embodiment of the present invention.

FIG. 8 is a diagram showing another configuration example of the printer according to the third embodiment of the present invention.

FIG. 9 is a diagram showing a configuration example of a printer according to a fourth embodiment of the present invention.

FIG. 10 is a diagram for explaining an example in which a transmissive sensor is used as the meandering range detection sensor in the fifth embodiment of the present invention.

FIG. 11 is a block diagram showing an example of a control system of a meandering correction roller in a fifth embodiment.

FIG. 12 is a diagram illustrating a printer according to a fifth embodiment.

FIG. 13 is a diagram illustrating a printer according to a sixth embodiment of the present invention.

FIG. 14 is a block diagram showing an example of a control system of a meandering correction roller in a sixth embodiment.

FIG. 15 is a diagram illustrating a printer according to a seventh embodiment of the present invention.

FIG. 16 is a block diagram showing an example of a control system of a meandering correction roller according to a seventh embodiment.

FIG. 17 is a block diagram of a printer according to an eighth embodiment of the present invention.

FIG. 18 is a diagram illustrating a conventional belt meandering prevention mechanism.

[Explanation of symbols]

1 ... Belt, 4 ... Meandering correction roller, 11 ... Heating roller,
12 ... Non-heating roller, 13, 14 ... Pressing roller, 15 ...
Lapping section, 16 ... Pressure roller, 17 ... Writing head, 18 ... Developing device, 20 ... Paper, 21 ₁ , 21 ₂ ... Bellows section, 24 ... Swirl section, 26, 29 ... Sensor, 27 ... Schmitt trigger circuit, , 28, 34 ... Flip-flops,
30, 32 ... Not circuit, 31, 33 ... AND circuit, 3
5 ... OR circuit, 36 ... Meandering correction roller drive circuit.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location G03G 21/20 G03G 21/00 534

Claims (3)

[Claims] 1. An endless dielectric belt that is conveyed, a writing head that forms an electrostatic latent image on the dielectric belt, a developing unit that forms a toner image on the electrostatic latent image, and the toner. A transfer means for transferring an image to a recording medium by at least heat, a dielectric belt heated to a high temperature by the transfer means, and a dielectric belt from the developing means to the transfer means are rubbed together to perform heat exchange. And a length of a section of the rubbing by the rubbing section is L1, and a length of a belt path in a section from the exit of the rubbing section to the developing means of the dielectric belt. , L2 is longer than L1. 2. The printer according to claim 1, further comprising a plurality of rollers at a position where the dielectric belt comes into contact with the belt in a section from when the dielectric belt comes out of the rubbing section to when it enters the developing means. 2. The printer according to claim 1, wherein the roller is folded back with a length shorter than L1 to form a belt path in a compact space. 3. An endless dielectric belt that is conveyed, a writing head that forms an electrostatic latent image on the dielectric belt, a developing unit that forms a toner image on the electrostatic latent image, and the toner. A transfer means for transferring an image to a recording medium by at least heat, a dielectric belt heated to a high temperature by the transfer means, and a dielectric belt from the developing means to the transfer means are rubbed together to perform heat exchange. An aligning portion, a meandering correction roller for correcting the meandering of the dielectric belt, a driving means for driving the meandering correction roller, an electrostatic latent image formed by the writing head, and a toner image formed by the developing means. The electrostatic latent image is formed by the writing head, the toner image is formed by the developing unit, and the transfer operation is performed more than the period when the transfer unit does not completely transfer the toner image. Control means for controlling the driving means so that the dielectric belt moves within a narrower range in the width direction of the dielectric belt during any one of the transfer of the toner image by A printer having a plurality of sensors for detecting a meandering range of a dielectric belt and inputting a detection result to the control means.