JPH0743729Y2 - Image forming device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an image forming apparatus used in a printer, a copying machine or the like.

(Prior Art) Conventionally, when forming an image in a printer or a copying machine, an electrophotographic recording method based on the Carlson method is generally used ("Basics and Applications of Electrophotographic Technology", edited by The Institute of Electrophotography (1988). Issued on June 15th by Corona) (See P28, 46, 47).

FIG. 3 is a conceptual diagram of an image forming apparatus using the electrophotographic recording method of the Carlson method.

In the figure, the image on the original read by the optical means is first exposed by the exposure device 3 of the photosensitive drum 2 charged by the corona discharge of the corona discharger 1 to form an electrostatic latent image. The electrostatic latent image is developed by the developing device 4, then transferred onto the recording medium 8 by the transfer device 5, and fixed by the fixing device 6 to form an image.

Since the photosensitive drum 2 is repeatedly used, the residual toner after the transfer is cleaned by the cleaning device 7.

However, in the above-mentioned conventional image forming apparatus, since the transfer process by the electrostatic action is used, the transfer rate is poor, and the process of cleaning the residual toner on the photosensitive drum 2 after the transfer is required. Maintenance work is required to discard the toner collected here.
Then, when the toner is discarded, there is a problem that the body and clothes are soiled and the toner is scattered inside and outside the apparatus.

In addition, there are many processes from the formation of the electrostatic latent image to the fixing of the toner image on the recording medium 8, which not only complicates the apparatus but also increases the size thereof. Therefore, an image forming apparatus that does not require a cleaning device on the photosensitive drum 2 and can be downsized is provided.

FIG. 4 is a schematic configuration diagram of an image forming apparatus that does not require a cleaning device on the photosensitive drum.

In the figure, a drum-shaped electrostatic latent image carrier 101 constituted by providing a photoconductive layer 101b on a conductive support 101a is rotated at a constant peripheral speed in a direction of an arrow by a driving unit (not shown).
Reference numeral 102 denotes an endless development target, which is stretched between the electrostatic latent image carrier 101 and the pressure roll 103. The object to be developed 102 has an insulating property and is formed into a film shape.
It moves in the direction of the arrow due to the frictional force with 101.

Next, the operation of the image forming apparatus having the above configuration will be described.

First, the electrostatic latent image carrier 101 is uniformly and uniformly charged by using the charging device 104 provided so as to face its surface. Then, the developing object 102 comes into close contact with the electrostatic latent image carrier 101 and moves at a constant speed between the charging process and the exposure process.

Next, the exposure device 105 transmits light through the object 102 to be developed and irradiates the electrostatic latent image carrier 101 with light corresponding to an image signal to form an electrostatic latent image.

The developing device 106 is a member to be developed that is in close contact with the electrostatic latent image carrier 101.
The toner 10 is disposed on the toner carrier 107 so as to face the toner carrier 102.
8 is adsorbed and conveyed in the direction of the arrow, and is attached onto the development target 102 corresponding to the electrostatic latent image formed on the electrostatic latent image carrier 101. At this time, electric force lines associated with the electrostatic latent image formed on the electrostatic latent image carrier 101 are generated in the space between the toner bearing member 107 and the developed member 102 penetrating the developed member 102. For this reason, the charged toner 108 on the toner carrier 107 adheres to the object 102 to be developed by electrostatic force and is developed to form a toner image.

After that, the development target 102 separated from the electrostatic latent image carrier 101 is conveyed to a transfer / fixing unit including a pressure roll 103 and a heat generation roll 113. The development target 102 on which the toner image is formed and the final recording support 114 sent from the paper feed cassette 120 via the paper feed roll 115 are overlapped here, and heated and pressed.
The heat of the heat-generating roll 113 melts the toner 108 on the development target 102 via the final recording support 114, penetrates the fibers of the final recording support 114 by the pressure action, and the transfer and the fixing are simultaneously performed.

On the other hand, a small amount of toner 1 is left on the developed material 102 after transfer and fixing.
Although 08 may remain, it is removed by the fixing cleaner 118 provided so as to press the pressure roll 103.
At this time, the state of the toner 108 is still in the molten state in the fixing portion, so that the residual toner can be easily removed.

On the other hand, the electrostatic latent image carrier 101 is the object to be developed 1 after the development process.
After separated from 02, the entire surface is irradiated with light by the static elimination lamp 119, which is a static elimination unit, to remove the residual charges. In this way, the electrostatic latent image carrier 101 is repeatedly used.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional image forming apparatus, when a plurality of sheets of recording are performed, the electrostatic latent image carrier 101 and the pressure roll on which the developed object 102 is stretched are stretched. 103, tension roll 111
Of the electrostatic latent image carrier 101 and the pressure roll 103 depending on the processing accuracy, manufacturing accuracy, and assembly accuracy when assembling the image forming apparatus.
Parallelism between the pulling roll 111 and the pulling roll 111 decreases, and
Depending on the accuracy of the length of 02 and the like, the development target 102 that is in close contact with the electrostatic latent image bearing member 101 may shift in the longitudinal direction of the electrostatic latent image bearing member 101 and meander.

Various methods have been proposed to prevent this meandering. For example, the endless belt is stretched by forming flanges at both ends of one or more rollers among the plurality of rollers on which the endless belt is stretched, or forming perforation holes at the edges of the endless belt. One or more of the multiple rollers have a sprocket to prevent meandering, or a ring-shaped guide groove is provided at one end of the roller and a guide is provided inside the endless belt to prevent meandering. (See JP-A-63-75779).

However, when the flange is used, both ends of the endless belt are easily damaged, and when the sprocket is used, the perforation holes are easily damaged, which makes it difficult to replace the endless belt.

Further, there is a method of preventing the meandering by providing restriction members at both ends of the endless belt (see Japanese Patent Publication No. 64-978), but the manufacturing cost is high and it is not easy to replace the endless belt.

In addition, there is a method of preventing a meandering by attaching a Tyco type crown to one or more of a plurality of rollers on which the endless belt is stretched, but it is effective when the endless belt is stretchable. In the case of the developed object 102 used in the image forming apparatus, if an elastic material is used, the image will be disturbed.

On the other hand, there has been proposed a method of using a yawing roll in addition to a plurality of rollers on which an endless belt is stretched (JP-A-57-673 and JP-A-58-21413). reference). This method is effective and practical for correcting the meandering of the developed object 102 having a wide width and a thickness of several hundreds μm or less as in an image forming apparatus.

FIG. 5 is a diagram showing an image forming apparatus using a yawing roll.

In the figure, a yawing roll 121 is arranged downstream of the electrostatic latent image carrier 101 and upstream of the pressure roll 103. A solenoid (not shown) and a recovery spring (not shown) are provided at one end of the yawing roll 121.
Is arranged so as to be able to swing in the CD direction around the shaft end side where the shaft is not connected.

FIG. 6 is a diagram showing the direction in which the yawing roll is moved.

As shown in the figure, when the wrapping angle of the development target 102 wound around the yawing roll 121 is θ, the yawing roll 121 is placed in the normal direction CD to the bisector AB of the wrapping angle. To move.

FIG. 7 is a perspective view of a main part of a conventional image forming apparatus.

In the figure, 122 is a solenoid, 123 is a pin, 124 is a restoring spring, and 125 and 126 are sensors. The shaft of the solenoid 122 is connected to the shaft end of the yawing roll 121 by a pin 123. The solenoid 122 is arranged so as to be able to move the yawing roll 121 in the EF direction (corresponding to the CD direction in FIG. 5), and the restoration spring 124 is provided for the restoration operation of the solenoid 122. It is arranged so that it can be restored when it is needed.

Further, the yawing roll 121 is swung about the shaft end side where the shaft of the solenoid 122 is not connected.

When a voltage is applied to the solenoid 122, the shaft is attracted by the magnetic force, and the yawing roll 121 is moved in the F direction in the figure. As a result, the development target 102 moves in the direction H in the figure due to the frictional force between the yawing roll 121 and the development target 102. Further, when no voltage is applied to the solenoid 122, the shaft is attracted by the force of the recovery spring 124, and the yawing roll 121 is moved in the E direction in the figure.
As a result, the frictional force between the yawing roll 121 and the development target 102 causes the development target 102 to move in the G direction in the figure. In this way, the meandering of the development target 102 can be corrected by the yawing roll 121, the solenoid 122, and the restoration spring 124.

The position of the developed object 102 is detected by the two sensors 125 and 126.
Done by The positions of the two sensors 125 and 126 may be on either the inner or outer surface of the loop of the development target 102, and as long as there is no reflection on the periphery of the development target 102 other than the development target 102. You can place it anywhere.

FIG. 8 is a block diagram of a control circuit for operating the yawing mechanism.

In the figure, 127A and 127B are comparators, 128 is a flip-flop, and 129 is a power supply. The comparators 127A and 127B compare the output voltage of the light receiving part of the sensors 125 and 126 with the reference voltage.If the reference voltage is set to 3V, if the output voltage of the sensors 125 and 126 is 3V or less, 0V becomes 3V. In the above cases, 5V is output.

The output of the comparators 127A and 127B is the flip-flop 1
28, the flip-flop 128 outputs 0V or 5V depending on the states of the two input signals. When the output signal of this flip-flop 128 is 5V, the power supply 129 is a solenoid.
A voltage is applied to 122 to operate solenoid 122.

For example, in FIG. 7, the development target 102 moves in the direction G in the figure, and the development unit 102 is detected by the light receiving portion of the sensor 125. When the output voltage of the sensor 125 exceeds 3V, the voltage from the power supply 129 to the solenoid 122 is increased. Is applied, the yawing roll 121 is moved in the F direction by the solenoid 122,
Moves in the H direction. Then, when the development target 102 moves to a position in the H direction, the development unit 102 is detected by the light receiving portion of the sensor 126 on the opposite side, and when the output voltage of the sensor 126 exceeds 3V, the development target 102 is added to the solenoid 122. The voltage that was being supplied is cut off. As a result, the restoring spring 124 moves the yawing roll 121 in the E direction, and
02 moves in the G direction again. By repeating this series of operations, the meandering of the development target 102 is controlled within a predetermined range.

As described above, by moving the yawing roll 121 in the direction C or D shown in FIG. 5 (FIG. 5), a frictional force is generated between the yawing roll 121 and the development target 102, and the development target
102 meandering can be corrected. However, when recording is performed for a long time using this device, the final recording support 114
There are several diagonal black streaks. Then, finally, the development target 102 is cut and the image recording becomes impossible.

This is for the purpose of correcting the meandering of the development target 102, and the development target 102
By tilting the yawing roll 121 with respect to the wrinkle, wrinkles are generated only before and after the yawing roll 121 of the development target 102, that is, between the electrostatic latent image carrier 101 and the yawing roll 121, and between the yawing roll 121 and the pressure roll 103. This is because.

Since the pressure roll 103 and the heat-generating roll 113 are in pressure contact with each other when the developed object 102 has wrinkles, the wrinkles of the developed object 102 are fixed. Then, since the toner 108 adheres to the tip of the wrinkle regardless of the electrostatic latent image, several diagonal black streaks are generated in the non-image portion of the final recording support 114. Further, if the recording is continued for a long time as it is, the fixed wrinkles are repeatedly pressed against each other at the transfer / fixing portion, so that the creases are cracked and the developed object 102 is damaged.

The present invention solves the problems of the conventional image forming apparatus described above, prevents the yawing roll that corrects the meandering of the developing material from generating wrinkles on the developing material, and records a stable image for a long time. It is an object of the present invention to provide an image forming apparatus capable of performing the above.

(Means for Solving the Problems) Therefore, in the image forming apparatus of the present invention, the electrostatic latent image bearing member and the development target on which the sheet-shaped film is formed in an endless shape are partially contacted with each other. Then, a developing device is provided so as to face the above-described object to be developed, which is closely adhered to the electrostatic latent image carrier on which the electrostatic latent image is formed, and corresponds to the electrostatic latent image on the electrostatic latent image carrier. In an image forming apparatus for forming a toner image on a development target, one end is axially supported and the other end is swingably disposed in a longitudinal direction of the development target. ing.

Further, the yawing roll is arranged so as to slide with respect to the development target, and the disposition position is upstream of the electrostatic latent image carrier and downstream of the transfer / fixing unit.

(Operation) According to the present invention, since the yawing roll is swingably arranged so as to slide with respect to the development target as described above, by swinging the yawing roll, It is possible to generate a frictional force between the developing bodies and move the developing body laterally.

Further, the yawing roll is disposed at the upstream side of the electrostatic latent image carrier and the downstream side of the transfer / fixing unit. Wrinkles may be generated on the developed material that has passed through the yawing roll due to straightening, but since there is no transfer unit on the downstream side, the developed material is not pinched and fixed by the transfer unit roll. .

(Example) Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention.

In the figure, an electrostatic latent image carrier 101 formed in a drum shape.
Is rotated at a constant peripheral speed in the direction of the arrow by a driving means (not shown). This electrostatic latent image carrier 101 is a conductive support 101a.
With the photoconductive layer 101b provided thereon, any of a selenium photoconductor, an organic photoconductor, a zinc oxide photoconductor, an amorphous silicon photoconductor, and the like can be used. In this embodiment, a positive charge type organic photoconductor in which a charge transport layer and a charge generation layer are laminated in order on the conductive support 101a is used as the photoconductive layer 101b.

Reference numeral 102 denotes an endless development target, and the development target 102 is stretched around an electrostatic latent image carrier 101, a pressure roll 103, and a pulling roll 111. The development target 102 moves in the direction of the arrow due to the frictional force of the electrostatic latent image carrier 101. Then, the development target 102
The pulling roll 111 is provided with a tensioning mechanism for applying an appropriate tension to the development target 102 so that the electrostatic latent image carrier 101 moves at the same speed.

The developed material 102 used here is required to have translucency adapted to the wavelength of the light source at the time of exposure, insulating property at the time of development, and heat resistance at the time of transfer / fixing. Films made of materials such as polyimide, polyetherimide, polyethersulfone, and polyetheretherketone are used.

Next, the image forming process in this embodiment will be described.

First, the electrostatic latent image carrier 101 is uniformly and uniformly charged by the charging device 104 as a charging means provided so as to face the surface thereof. A corona charger, which is generally shown, is used as the charging device 104, but a brush charger or the like can also be used. The developing object 102 comes into close contact with the electrostatic latent image carrier 101 between this charging process and the next exposure process.

In the exposure process, light corresponding to an image signal is transmitted through the development target 102 by the exposure device 105 serving as an exposure unit to irradiate the electrostatic latent image carrier 101 to form an electrostatic latent image. As the exposure device 105, in addition to the combination of the LED array and SELFOC lens (trade name) used here, any combination of a laser and an image forming optical system can be used.

Next, the developing device 106 is provided so as to face the object to be developed 102 that is in close contact with the electrostatic latent image carrier 101. This developing device 106
The toner 108 is adsorbed on the toner carrier 107, conveyed in the direction of the arrow in the figure, and developed on the developed object 102 that is in close contact with the electrostatic latent image formed on the electrostatic latent image carrier 101. In this embodiment, reversal development is used, and the conductive support 1 of the electrostatic latent image carrier 101 is used.
A bias potential is applied between 01a and the toner carrier 107.

With the above-described configuration, lines of electric force associated with the electrostatic latent image formed on the electrostatic latent image carrier 101 are generated in the space between the toner carrier 107 and the developer 102 penetrating the developer 102. For this reason,
The charged toner 108 on the toner carrier 107 adheres to the object 102 to be developed by electrostatic force and is developed to form a toner image. As the developing device 106, any one of a two-component magnetic brush developing device, a one-component magnetic brush developing device, a one-component non-magnetic developing device and the like can be used.

When the electrostatic latent image carrier 101 and the development target 102 are separated, AC
The corona charger 112 removes the charges on the development target 102, and prevents the toner image from being disturbed due to the discharge at the time of separation.

After that, the development target 102 separated from the electrostatic latent image carrier 101 is conveyed to a transfer / fixing unit including a pressure roll 103 and a heat generation roll 113.

On the other hand, the final recording support 114 contained in the paper cassette 120.
(Generally, paper is used.) Is taken out by the paper feed roll 115 and sent to the paper feed roll 116 whose rotation is stopped, and the skew of the final recording support 114 is corrected. Here, the paper feed roll 116 is activated, the final recording support 114 is sent to the transfer / fixing section, and the development target 102 on which the toner image is formed is formed.
It is piled up and heated and pressurized. And the heating roll 113
Of the heat is transmitted through the final recording support 114 to melt the toner on the development target 102, and is permeated between the fibers of the final recording support 114 by a pressing action to transfer and fix onto the final recording support 114. Are done at the same time. Final record support 114 transferred and fixed
Is delivered to the outside of the apparatus by the paper discharge roll 117.

On the other hand, although a small amount of toner 108 may remain on the developed object 102 after the transfer / fixing, a fixing cleaner 118 provided so as to press-contact the developed object 102 on the pressure roller 103.
Are removed by. At this time, the toner 108 can be easily removed because the molten state in the fixing portion is still continuing.

In addition, the electrostatic latent image carrier 101 is a member to be developed 1 after the development process.
Separated from 02, the entire surface is irradiated with light by the static elimination lamp 119 which is the static elimination means, and the residual charges on the electrostatic latent image carrier 101 are removed. In this way, the electrostatic latent image carrier 101 is repeatedly used.

Here, the yawing roll 121 is the electrostatic latent image carrier 101.
Is arranged on the upstream side of the pull roll 111 and on the downstream side of the pull roll 111.

FIG. 2 is a schematic configuration diagram of an image forming apparatus showing a second embodiment of the present invention.

The position of the yawing roll 121 in FIG.
Has been changed to the upstream side of. Here, the case where the yawing roll 121 is provided downstream of the electrostatic latent image carrier 101 in FIG. 5 and upstream of the pressure roll 103 and the case where the yawing roll 121 is upstream of the electrostatic latent image carrier 101 in FIG. When the yawing roll 121 is provided downstream of the pressure roll 103 and the pulling roll 111, and when the electrostatic latent image carrier 101 and the pulling roll 111 shown in FIG.
The object to be developed 10 when continuous printing is performed for a long time at three types of arrangement positions when the yawing roll 121 is provided downstream of
FIG. 9 shows the results obtained by examining the wrinkle generation state 2 and the meandering correction state of the development target 102.

As shown in the figure, the meandering of the development target 102 can be corrected regardless of the position of the yawing roll 121.
However, regarding wrinkling of the developed object 102 and fixing of the wrinkles, the yawing roll 121 is used upstream of the electrostatic latent image carrier 101 and downstream of the pressure roll 103 (see FIG. 1). , FIG. 2) can be suppressed.

In the case of the conventional image forming apparatus shown in FIG. 5, a yawing roll is used.
Immediately downstream of 121, there are a heat-generating roll 113 and a pressure roll 103 for pressing and constraining the developed material 102. The narrow pressure generated by the heat-generating roll 113 and the pressure roll 103 causes the rolling member such as the pulling roll 111 and the electrostatic latent image carrier 101 shown in FIGS.
A stronger binding force than the binding force given to 102 is given to the development target 102. Therefore, even if the developing target 102 is moved in the longitudinal direction by the yawing roll 121 to correct the meandering of the developing target 102, the developing target 1 is affected by the pressure roll 103.
It is difficult to move 02 in the longitudinal direction. This causes it to be inferior to the other two methods in correcting meandering.

When the wrinkled object to be developed 102 enters between the heat generating roll 113 and the pressure roll 103 arranged in pressure contact with the heat generating roll 113, the wrinkle is pressed and fixed by the pressure.

On the other hand, in the case of FIGS. 1 and 2, the yawing roll is used.
Immediately downstream of 121 is a pulling roll 111 or an electrostatic latent image carrier.
101 rolling elements are arranged. These are the development target 102
Since the restraining force applied to the developing member 102 is not so strong, the to-be-developed member 102 is easily moved in the longitudinal direction by the yawing roll 121. Further, it is stretched around a pulling roll 111. The development target 102 moves in the direction of the arrow due to the frictional force of the electrostatic latent image carrier 101. Then, since there is no member disposed in pressure contact with the pulling roll 111 or the electrostatic latent image carrier 101 so that the developed object 102 moves at the same speed as the electrostatic latent image carrier 101, this occurs. I am not fixed.

The present invention is not limited to the above embodiment,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) As described in detail above, according to the present invention, the electrostatic latent image is formed by the structure in which the electrostatic latent image carrier and the endless developed member are partially in contact with each other. In an image forming apparatus that forms a toner image corresponding to an electrostatic latent image of a developing object that is closely adhered to an electrostatic latent image bearing member, the position of a yawing roll that corrects the meandering of the developing object is set to the electrostatic latent image bearing member. Since it is placed upstream of the body and downstream of the pressure roll, wrinkles do not occur on the developed object,
You can record stable images for a long period of time,
In addition, the life of the developed object becomes longer.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus showing an embodiment of the present invention, FIG. 2 is a schematic configuration diagram of an image forming apparatus showing a second embodiment of the present invention, and FIG. 3 is an electronic photograph by the Carlson method. FIG. 4 is a conceptual diagram of an image forming apparatus using a recording method, FIG. 4 is a schematic configuration diagram of an image forming apparatus that does not require a cleaning device on a photosensitive drum, and FIG. 5 is an image forming apparatus using a conventional yawing roll. FIG. 6 is a view showing the direction in which the yawing roll is moved, FIG. 7 is a perspective view of a main part of a conventional image forming apparatus, FIG. 8 is a control circuit block diagram for operating the yawing mechanism, and FIG. The figure is a comparison diagram of wrinkles and meandering of the object to be developed. 101 ... Electrostatic latent image carrier, 101a ... Conductive support, 101b
...... Photoconductive layer, 102 ・ ・ ・ Development target, 104 …… Charging device, 10
5 ... Exposure device, 106 ... Developing device, 107 ... Toner carrier, 108 ... Toner, 111 ... Pull roll, 114 ... Final recording support, 121 ... Yawing roll.

Claims (1)

[Scope of utility model registration request] 1. An electrostatic latent image bearing member on which an electrostatic latent image is formed by disposing an electrostatic latent image bearing member and a development target having a sheet-like film formed in an endless shape so as to partially contact with each other. An image forming apparatus for forming a toner image corresponding to the electrostatic latent image on the electrostatic latent image carrier on the developing object by providing a developing device so as to face the object to be developed that is closely adhered to (A) A yawing roll pivotally supported is slidably arranged with respect to the object to be developed, and (b) the arranged position is located upstream of the electrostatic latent image carrier. An image forming apparatus characterized by being located downstream of the transfer / fixing unit.