JPH09237027A - Electrophotographic printer - Google Patents

Abstract

(57) [Abstract] [PROBLEMS] To prevent a change in the electrical characteristics of each part arranged in an image forming chamber or a large positional deviation between the parts due to a temperature change in a use environment. . An image forming chamber A in which a photoconductor drum 2 and an exposure device 5 are arranged, and a thermal fixing chamber B in which heat fixing devices 8 and 9 are arranged by a partition plate 10 inside a casing 1. In addition to the above, the fan member 11 rotating forward and backward for introducing air into the image forming chamber A or the heat fixing chamber B is attached to the housing 1 or the partition plate 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic printer that forms an image using an electrophotographic system.

[0002]

2. Description of the Related Art A conventional electrophotographic printer, as shown in FIG. 4, has a casing 31 made of a plastic material such as polycarbonate or ABS and a photosensitive drum 32 or LED having a photosensitive layer such as amorphous silicon inside a casing 31. An image forming unit including the array head 33 and the like and a heat fixing device including a heat roller 34 and a pressure roller 35 are arranged, and the LED is formed on the photoconductor layer of the photoconductor drum 31 in the image forming unit. A predetermined electrostatic latent image is formed by irradiating light from the array head 33, and a predetermined toner image is formed by attaching toner to the electrostatic latent image, and then the toner image is recorded on recording paper by the thermal fixing device. It functions as an electrophotographic printer by heat fixing and forming a predetermined image on recording paper.

In such an electrophotographic printer, the heat roller 34 constituting the heat fixing device has a structure in which a heating element such as a halogen lamp is arranged inside a metal cylinder coated with fluororesin. It takes a relatively long time (2 to 3 minutes) to raise the temperature to the temperature (100 to 150 ° C.) necessary for fixing the toner. Therefore, in order to keep the electrophotographic printer ready for use after turning on the manual switch 37, the heat roller 34 is continuously supplied with electric power to keep the heat roller 34 at 100-1.
A temperature of 50 ° C had to be maintained.

In the electrophotographic printer described above,
A cooling fan 36 is attached to the wall surface of the casing 31, and the cooling fan 36 discharges the air in the casing 31 that has become high temperature due to the heat generated by the heat roller 34 to the outside.

[0005]

However, in this conventional electrophotographic printer, the heat generated by the heat roller 34 diffuses through the air into the entire casing 31, so that the inside of the casing 31 is highly accurate. Cannot be cooled to
In addition, the cooling fan 3 is used while the electrophotographic printer is being used so that the components forming the image forming unit do not become hot.
It is necessary to constantly rotate 6 at a high speed, which has a drawback that power consumption becomes large.

Moreover, since the cooling fan 36 is stopped at the same time when the manual switch 37 is turned off, the temperature inside the housing 31 immediately after the manual switch 37 is turned off is due to the dissipation of heat accumulated in the heat roller 34. When the temperature rises rapidly to about 50 ° C and is in such a state,
When the electrophotographic printer is used with the manual switch 37 turned on, the temperature in the housing 31 becomes higher, causing a large positional deviation in each component forming the image forming unit, or the electrical characteristics of each component. It induces the drawback that the value changes drastically.

Further, in such a conventional example, there is a similar problem when the electrophotographic printer is used in an environment of extremely low temperature (room temperature: 5 ° C. or less), and each component in the housing 31 has the same problem. In the meantime, a large positional deviation may occur due to a temperature change, or the electrical characteristics of each component may change significantly.

[0008]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-described drawbacks, and an image forming chamber in which a photosensitive drum and an exposure device are arranged is provided by a partition plate inside the housing, and It is divided into a heat fixing chamber in which a fixing device is disposed, and a fan member that rotates forward and backward to introduce air into the image forming chamber or the heat fixing chamber is attached to the housing or partition plate. It is characterized by being formed.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic view showing an embodiment of an electrophotographic printer of the present invention. 1 is a housing, 2 is a photosensitive drum, 5 is an LED array head as an exposure device, 8 is a heat roller, and 9 is a heat roller. Is a pressure roller, 10 is a partition plate, 11 is a fan member, A is an image forming chamber, and B is a heat fixing chamber.

In the electrophotographic printer shown in FIG. 1, an image forming chamber A in which a photosensitive drum 2 and an LED array head 5 are arranged by a partition plate 10 is provided inside a housing 1 made of a plastic material such as polycarbonate or ABS. And a heat fixing chamber B in which a heat fixing device composed of a heat roller 8 and a pressure roller 9 is disposed, and a positive member for introducing air into the image forming chamber A or the heat fixing chamber B in the partition plate 17. It has a structure in which a rotating and reverse rotating fan member 11 is attached.

The image forming chamber A is a chamber for forming a predetermined toner image according to an image signal. Inside the image forming chamber A, a photosensitive drum 2 rotatably supported is arranged, and around the photosensitive drum 2. It has a cleaner 3, a charger 4, an LED array head 5, a developing device 6, and a transfer roller 7.

The photosensitive drum 2 is made of amorphous silicon (a) on the outer peripheral surface of a cylindrical substrate made of aluminum or the like.
-Si) is formed by depositing a photoconductor layer made of a photoconductive material such as Si by a well-known plasma CVD method, a sputtering method, or the like, and is rotatable at a predetermined position in the housing 1 (direction of an arrow in the figure). Supported by.

A cleaner 3 arranged around the photosensitive drum 2 is for removing the residual toner on the surface of the photosensitive drum. As such a cleaner 3, for example, a blade made of elastic rubber or a magnetic material is used. A brush or the like is used.

Further, with respect to the rotation direction of the photoconductor drum 2, a charger 4, LE is provided on the downstream side of the cleaner 3.
The D array head 5, the developing device 6, and the transfer roller 7 are sequentially arranged.

The charger 4 is for charging the photoconductor layer of the photoconductor drum 1. As such a charger 4, for example, a corona charger or the like is used.

In the LED array head 5, a large number of light emitting diode (LED) elements are linearly arranged at a linear density of, for example, 300 dpi (dots / inch) on a substrate made of glass epoxy resin or the like, and L
It has a structure in which an imaging lens such as a rod lens array or an aspherical lens is arranged above the ED element.
The ED element selectively emits light based on an image signal, and irradiates the charged photoconductor layer with these lights to form a predetermined electrostatic latent image on the photoconductor layer.

The developing device 6 includes a developing sleeve 6a.
And a developer storage container 6b. The developer in the developer storage container 6b adheres in accordance with the electrostatic latent image on the surface of the photoconductor drum to make it visible. As the developer, for example, a two-component developer such as a conductive magnetic carrier and an insulating toner or a magnetic insulating toner is used.

Further, the transfer roller 7 is arranged so as to face the photoconductor drum 2 with the recording paper p interposed therebetween, and the toner image adhered on the photoconductor drum 2 by the above-described development process is recorded on the recording paper p. It has the function of transferring to.

On the other hand, the thermal fixing chamber B is a chamber for applying heat to the toner image transferred onto the recording paper p to thermally fix the toner on the recording paper p, and the inside thereof is pressed against each other. The heat fixing device is composed of a heat roller 8 and a pressure roller 9 that are rotatably supported in this state.

The heat roller 8 has a structure in which a fluorocarbon resin is coated on the outer circumference of a metal cylindrical body made of aluminum or the like, and a halogen lamp as a heating element is arranged inside the cylindrical body. Radiant heat is continuously applied to maintain the surface of the heat roller 8 at a constant temperature (100 to 150 ° C.) necessary for fixing the toner.

The pressure roller 9 is for transporting the recording paper p in a predetermined direction while urging it toward the heat roller 8 and has a structure in which a fluorine resin or the like is adhered to a metal shaft member. Have

The heat fixing chamber B and the various parts in the image forming chamber A described above are adapted to control the power supply from an external power source by turning on / off the manual switch 15.

The partition plate 10 arranged between the image forming chamber A and the heat fixing chamber B is for cutting off heat conduction between the image forming chamber A and the heat fixing chamber B. .5
Low thermal conductivity material of W / m · k or less, for example, 1 to 2 m depending on plastic materials such as polycarbonate and ABS
It is formed with a thickness of m. In addition, this partition plate 10
Is preferably formed of a low heat conductive material having a conductivity of 0.2 to 0.5 W / m · k.

Further, on the wall surface of the partition plate 10, there are provided a window portion 10a to which the fan member 11 is attached, and an opening portion 10b for conveying the recording paper p from the image forming chamber A to the heat fixing chamber B. doing.

The fan member 11 can rotate in both forward and reverse directions, and the temperature in the image forming chamber A is set to a predetermined temperature (28 to 28) suitable for forming a toner image.
It maintains the temperature at 32 ° C).

The fan member 11 is an AC (not shown).
Driven by a motor or a DC motor, the temperature inside the image forming chamber A is a predetermined reference temperature (first reference temperature:
When the temperature is higher than 30 to 31 ° C.), the positive air rotates to create a flow of air that directs the outside air into the heat fixing chamber B via the image forming chamber A, and the temperature in the image forming chamber A is the same as the first temperature. The second reference temperature (26-
When the temperature is lower than 27 ° C., the air in the heat fixing chamber B is introduced into the image forming chamber A by rotating in the reverse direction. When the rotation of the fan member 11 is reversed, for example, when a DC motor is used, the positive and negative electrodes of the power source connected to the DC motor may be reversed.

In order to operate the fan member 11 as described above, the motor includes a drive circuit 12a and a comparison circuit 12b, and a temperature detecting element 13 such as a thermistor arranged at a predetermined position in the image forming chamber A. Are connected, and the output voltage of the temperature detecting element 13 is compared with the reference voltage corresponding to the first reference temperature and the second reference temperature by a comparison circuit 12b using an operational amplifier. Is higher than the first reference voltage corresponding to the first reference temperature, the drive circuit 12a is driven to drive the fan member 11 in the forward direction (air in the image forming chamber A is sent into the heat fixing chamber B). Direction), and while the output voltage of the temperature detection element 13 is lower than the second reference voltage corresponding to the second reference temperature, the drive circuit 12a is driven to reverse the fan member 11. Controls to rotate in direction (a direction to send the air in the heat fixing chamber B into the image forming chamber A). still,
The drive circuit 12a and the comparison circuit 12b are connected to the external power source through the above-mentioned manual switch 15, and the fan member 11 is not operated after the switch 15 is turned off.

At this time, on the wall surface of the casing 1, a window portion 1a having a one-way valve 14 attached at a position close to the image forming chamber A is provided.
And a window portion 1b is provided at a position close to the heat fixing chamber B, and when the air in the heat fixing chamber B is introduced into the image forming chamber A, the air existing in the image forming chamber A is removed. Window 1a
When the air in the image forming chamber A is introduced into the heat fixing chamber B, the air in the heat fixing chamber B is discharged to the outside through the window 1b. The one-way valve 14 is attached to the housing 1 via a spring member (not shown),
It opens only when air moves between the image forming chamber A and the heat fixing chamber B.

As described above, the partition plate 10 is provided inside the housing 1.
The image forming chamber A and the heat fixing chamber B are divided by each other, and the partition plate 17 is attached with the fan member 11 which rotates forward and backward for introducing air into the image forming chamber A or the heat fixing chamber B. Therefore, when the temperature in the image forming chamber A is higher than the first reference temperature, the fan member 11 is normally rotated to introduce the air in the image forming chamber A into the heat fixing chamber B, and When the temperature in A is lower than the second reference temperature, the fan member 11 is rotated in the reverse direction so that the air in the heat fixing chamber B is introduced into the image forming chamber A.
Even if the heat generated by each component arranged in the image forming chamber A is gradually accumulated and the temperature in the image forming chamber A rises, if the temperature in the image forming chamber A exceeds the first reference temperature, The fan member 11 operates and the image forming chamber A is externally supplied until the temperature inside the image forming chamber A reaches a temperature (28 to 32 ° C.) suitable for image formation.
Even when the cool air is continuously introduced into the interior of the image forming room and the electrophotographic printer is used in an extremely low temperature environment (room temperature: 5 ° C. or less), the temperature in the image forming room A is suitable for image formation ( The warm air (temperature: 50 to 60 ° C.) in the heat fixing chamber B can be continuously introduced into the image forming chamber A until the temperature reaches 28 to 32 ° C.). As a result, the temperature inside the image forming chamber A is always maintained at a temperature suitable for image formation, the electrical characteristics and the like of each of the components housed therein can be kept substantially constant, and the temperature changes in the operating environment. It is possible to effectively prevent the occurrence of a large positional deviation.

Further, in this case, since the partition plate 10 is arranged between the image forming chamber A and the heat fixing chamber B, the temperature in the heat fixing chamber B rapidly rises immediately after the manual switch 15 is turned off. Even when the manual switch 15 is turned on again in this state, the temperature in the heat fixing chamber B is difficult to be transmitted to the image forming chamber A side, and the temperature in the image forming chamber A does not become high.

Moreover, since the partition plate 10 effectively blocks the heat generated by the heat roller 8 from attempting to diffuse into the entire housing 1, the diffusion of heat from the heat roller 8 is prevented. The cooling fan 11 can be stopped inside B to cool the inside of the housing 1 with high accuracy, and the cooling fan 11 does not need to be constantly rotated at a high speed, and the cooling fan 11 operates according to the temperature state in the image forming chamber A. By doing so, it becomes possible to save power consumption.

Thus, the electrophotographic printer described above is
(1) First, while rotating the photoconductor drum 1 in the image forming chamber A in the direction of the arrow in FIG. 1, the photoconductor layer is charged by the charger 4, and (2) the charged photoconductor layer is then formed. L
The ED array head 5 irradiates light to form a predetermined electrostatic latent image on the photoconductor layer of the photoconductor drum 1 based on the image signal. (3) Next, the electrostatic latent image on the photoconductor drum surface is developed by the developing device 6. Toner is attached to the latent image, (4) the toner attached to the photosensitive drum 1 is then transferred to the recording paper p by the transfer roller 7, and (5) finally, the recording paper p is opened in the opening 10b of the partition plate 10. The toner transferred onto the recording paper p via the heat fixing chamber B is heat-fixed by the heat fixing device (8, 9), and a predetermined image is formed on the recording paper p to form an electrophotographic printer. Function. (Other Embodiment) Next, another embodiment of the present invention will be described with reference to FIG.

The electrophotographic printer of this embodiment is different from that of the above-described embodiment in that, in the above-described embodiment, a fan member capable of rotating in the normal and reverse directions is attached to a partition plate, but in the present embodiment, In the first embodiment, the fan member 11 capable of rotating in the normal and reverse directions is attached to the wall surface of the housing 1 in which the heat fixing chamber B is provided, and the duct portion D communicating with the attachment portion of the fan member 11 is provided in the image forming chamber A and the heat fixing chamber. The partition plate 10 between B is provided so as to bypass the partition plate 10.

The duct portion D is divided into two passages, the passage 20a leading to the image forming chamber A and the passage 20b leading to the outside, inside the tip of the fan member 11, and one passage by the switching valve 21. By closing the fan member 1
The opening 1c of the heat fixing chamber B to which No. 1 is attached is connected to one of the paths 20a and 20b.

The switching valve 21 is connected to the comparison circuit 12b and the temperature detecting element 13 via the switching circuit 22, and the output voltage of the temperature detecting element 13 is higher than the first reference voltage corresponding to the first reference temperature. When it is higher or lower than the second reference voltage corresponding to the second reference temperature, the switching valve 21 is operated by driving the switching circuit 22 so as to close the path 20b communicating to the outside, and the temperature detection element 13 is operated. When the output voltage is between the first reference voltage and the second reference voltage, the switching valve 21 is switched to the switching circuit 2
It is operated so as to block the path 20a by the driving of No.2.

Further, the fan member 11 is similar to the above-described embodiment, when the output voltage of the temperature detecting element 13 is higher than the first reference voltage corresponding to the first reference temperature, the driving circuit 1
The air in the image forming chamber A is introduced into the heat fixing chamber B by positive rotation by 2a, and the output voltage of the temperature detecting element 13 is the second
When the voltage is lower than the second reference voltage corresponding to the reference temperature, the drive circuit 12a rotates in the reverse direction to introduce the air in the heat fixing chamber B into the image forming chamber A.

When the temperature in the image forming chamber A is maintained at a temperature between the first reference temperature and the second reference temperature, the switching valve 21 closes the path 20a leading to the image forming chamber A. The fan member 11 is rotated to evacuate the heat fixing chamber B.

The present invention is not limited to the above-described embodiments and examples, and various modifications and improvements can be made without departing from the gist of the present invention. For example, as shown in FIG. In the electrophotographic printer of the above embodiment, a heat insulating material 25 made of foamed polystyrene, sponge or the like may be attached to the inner wall of the image forming chamber A, or the number of windows formed in the image forming chamber A may be increased. in this case,
In addition to the same effects as those of the above-described embodiment, the heat retaining effect in the image forming chamber A is further improved by the heat insulating action of the heat insulating material 25.

In the electrophotographic printers of the above-described embodiments and examples, a laser scanner or the like may be used as the exposure device arranged in the image forming chamber A.

[0041]

According to the electrophotographic printer of the present invention, the temperature inside the image forming chamber is maintained at a temperature suitable for image formation, and the electrical characteristics of the respective parts disposed therein can be kept substantially constant. At the same time, it is possible to effectively prevent a large positional deviation between the components due to the temperature change of the use environment.

According to the electrophotographic printer of the present invention,
Immediately after turning off the power switch, even if the power switch is turned on again when the temperature inside the thermal fixing chamber rises sharply, the temperature inside the thermal fixing chamber is difficult to be transmitted to the image forming chamber side. The temperature inside the image forming chamber does not become high.

Further, according to the electrophotographic printer of the present invention,
The partition plate effectively blocks the heat generated by the heat fixing device from trying to diffuse into the entire housing, and the heat diffusion can be stopped in the heat fixing chamber to cool the inside of the housing with high accuracy. Need not be constantly rotated at high speed, and the power consumption can be saved by operating the cooling fan according to the temperature condition in the image forming chamber.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing an embodiment of an electrophotographic printer of the present invention.

FIG. 2 is a diagram schematically showing another embodiment of the electrophotographic printer of the present invention.

FIG. 3 is a diagram schematically showing another embodiment of the electrophotographic printer of the present invention.

FIG. 4 is a diagram schematically showing a conventional electrophotographic printer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Housing 2 ... Photosensitive drum 5 ... LED array head 8 ... Heat roller 9 ... Crimping roller 10 ... Partition plate 11 ... Cooling fan 13 ... Temperature detection element

Claims (1)

[Claims] 1. A partition plate divides the inside of the housing into an image forming chamber in which a photosensitive drum and an exposure device are arranged, and a thermal fixing chamber in which a thermal fixing device is arranged.
An electrophotographic printer, characterized in that the casing or the partition plate is formed by attaching a fan member that rotates forward and backward to introduce air into an image forming chamber or a heat fixing chamber.