JP3364536B2 - Airflow control method in copier - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air flow control method in an electrophotographic copying machine.

[0002]

2. Description of the Related Art In an electrophotographic copying machine (including image forming means for facsimiles and printers), a toner that is charged by being agitated in a developing device is usually used as an image carrier (hereinafter referred to as a photoconductor). It is developing the electrostatic latent image formed on the surface. The charge amount of the toner fluctuates depending on how the charge is applied to the toner and the developing method.

Generally, in the one-component development, since there is no carrier in the two-component development, the toner has a low charge amount. Further, in the case of using one-component development, in which the flight development is performed in which the development is performed while keeping a gap with the photoconductor, the charge amount of the toner is further reduced to facilitate the flight of the toner.

[0004]

However, while the toner having a low charge amount as described above has an advantage that it is easy to develop, it has a weak binding force to the photoconductor and the transfer material, and the toner of the transfer material is weak. Vibration and rampage due to transport,
There is a demerit in that it is easy to move, such as being attached to a member that is electrically charged.

Therefore, in a copying machine using such a toner, immediately after the transfer material passes through the transfer portion, when the transfer material passes through the joint of the guide plate, when the transfer material enters the fixing portion, and When the posture of the transfer material changes, the toner is easily separated from or moved from the transfer material, which causes toner scattering in the machine. In particular, in the case of a copying machine using an electrostatic transfer belt as the transfer / transport member, the transport force of the transfer material is large, so that the toner is largely scattered near the entrance of the fixing device.

The scattered toner pollutes the inside of the copying machine,
Further, the air flows for cooling the inside of the machine and is discharged to the outside of the machine while adhering to a member downstream of the flow path. Therefore, in this type of copying machine, toner is scattered not only inside the machine but also outside the machine.

The scattered toner in this machine adheres mainly to the vicinity of the entrance of the fixing device where the toner often scatters, especially to the outer cover of the fixing device. This fixing device is often operated by the user when a paper jam of the transfer paper occurs,
It is not preferable in terms of operation and appearance that toner adheres to the outer cover of the fixing device. In addition, the outer cover of the fixing device is often provided with a warning message such as "high temperature caution" to call the user's attention when operating, and the scattered toner is strongly attached to the outer cover. In that case, the warning display may not be readable and the safety for the user may be reduced.

The present invention has been made in view of the above points, and an object thereof is to keep scattered toner at a scattering position so as to reduce contamination inside the machine due to the scattered toner and suppress an increase in temperature inside the machine. An object of the present invention is to provide a method for controlling an air flow in a copying machine, which is capable of performing the above.

[0009]

To solve the above problems, the present invention provides, in claim 1, an image forming means for forming a toner image on an image carrier, a transfer means for transferring a toner image onto a transfer material, An electrophotographic copying machine having a cleaning means for collecting the toner image remaining on the image carrier and a fixing means for fixing the toner image transferred to the transfer material by heat, an outer cover of the fixing means, The image carrier has a cooling unit for generating an air flow for cooling the image carrier, and a heat exhaust unit for discharging heat generated by the air carrier for cooling the image carrier and the fixing unit out of the apparatus. A partition member is provided to cover the outer cover for eliminating the air flow between the fixing member and the transfer material passing portion to the fixing device, and the partition member covers the air flow containing the scattered toner that has cooled the image carrier. Exhaust along the outside of By discharging heat toward the exhaust heat means between the heat the outer cover and the partition member for generation of the fixing means, scattering bets cooling the image carrier
The heat generated by the air flow including the nozzle and the fixing unit is diverted to the vicinity of the heat discharging unit.

According to the second aspect of the present invention, an exhaust heat passage is provided for guiding the heat near the cleaning means from above the cleaning means to the heat exhausting means.

[0011]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 shows a sectional view of a copying machine equipped with the air flow control means of the present invention. In FIG. 1, a digital optical system 5 that uses a laser diode as an optical system to scan in a main scanning direction by a polygon scanner is used. This digital optical system is installed in an integral housing in order to avoid contamination of the mirror and the like due to scattered toner. Therefore, above the cleaning device 2, the discharging lamp 3, the charging device 4, the developing device 6 and the transfer device 7, which are necessary for forming the toner image centered on the photoconductor 1, are sufficient for heat radiation processing. There is no such space.

In FIG. 1, a photosensitive member 1 which has passed through a cleaning device 2, a charge eliminating lamp 3 and a charger 4 and is uniformly charged.
A latent image is formed by the optical system 5. This latent image is then developed by the developing device 6. As the developing system of this embodiment, non-contact developing using a one-component developer is used. Then, the toner image is transferred onto the transfer material by the transfer device 7. As the transfer device 7 in this embodiment, a transfer belt in which a bias is applied to a medium resistance belt is used.

The transfer material electrostatically adsorbed on the transfer belt is conveyed to the fixing device 9 and the transferred toner is fixed. At the transfer material transfer portion from the transfer belt to the fixing device 9, the posture of the transfer material is disturbed, so that the toner scattering as described above easily occurs. That is, the point indicated by reference numeral 12 in FIG. 1 is the place that is the main source of toner scattering.

On the other hand, in this type of copying machine, fans 10 and 11 are installed as cooling devices for preventing an increase in temperature inside the copying machine. The suction side fan 10 is located on the front side of FIG. 1 with respect to the paper passing portion, and the discharge side fan 11 is located on the back side of the side wall of the main body structure from the paper passing portion (FIG. 2). Here, a vent hole is formed in the side plate of the main body structure in the portion through which the air flow passes.

The suction side fan 10 is, as shown in FIG.
The outside air is taken in, divided by a duct, and the cool air is sent to the charger 4, the photoconductor 1, the cleaning device 2, and the polygon scanner motor. Of these, the flow 18 sent to the charger 4 is used for ozone treatment, and the flow 14 around the photoconductor and the flow 16 toward the polygon scanner motor are used for mechanical cooling. In addition, the discharge side fan 11 includes heat of the fixing device 9, heat of the polygon scanner motor, heat around the photoconductor, and further of a mechanical drive motor and a control board disposed on the back side with the side plate of the main body structure separated. Exhausting heat such as heat.

Here, as the air flow control method of the present invention, the partition plate 13 is directed upward from the upper guide shape of the fixing inlet portion.
a is provided. Furthermore, a partition plate 13b is provided to divide the space above the fixing device 9 into two parts, that is, the upper part and the lower part. As a result, the airflow drawn into the discharge side fan 11 is the flow 15 from the fixing device 9.
And a flow 16 for cooling the polygon scanner motor directly from the suction fan. The flow 14 for cooling around the photoconductor merges with the flow 16 for cooling the polygon scanner motor after cooling the cleaning unit and the transfer unit.
Therefore, the flow including the scattered toner from the photoconductor 1 is guided to the discharge side fan 11 without hitting the fixing device 9.

Therefore, according to the present embodiment, the scattered toner carried by the flow 14 (16) from the photoconductor 1 is less likely to adhere to the fixing device 9. Further, in this embodiment,
Since the flow passage cross-sectional area of the air flow from the photoconductor 1 is substantially reduced, the flow velocity is reduced, and the scattered toner discharge side fan 1
The movement to 1 is reduced, and the scattered toner can be retained at the toner scattering occurrence point.

However, in the embodiment shown in FIG. 1, the flow 14 (16) from around the photosensitive member causes a decrease in the flow rate, so that the exhaust heat around the photosensitive member, particularly at the cleaning device 2 is sufficiently exhausted. It will not be done. Therefore, in the second embodiment of the present invention, as shown in FIGS. 3 and 4, a path (flow path 17) for exhausting heat from above the cleaning device 2 is secured, and the heat of the cleaning unit is passed through this flow path 17. The heat around the photoconductor is discharged by releasing the heat.

By the way, the side plate of the main body structure is provided with holes along the side projection shape of the fixing device 9 in addition to the ventilation holes for air flow processing described above. This hole is a hole for supplying power to the fixing device 9 via the drawer connector, and the drawer connector is arranged on the inner side of the fixing device 9. For this reason,
In this copying machine, if the drive motor located on the inner side of the side plate of the main body structure and the heat exhausting means arranged on the inner side of the side plate of the main body structure for exhausting heat from the control board, the heat from the fixing unit and around the photosensitive member The flow containing the toner moves to the inner side of the side plate of the main body structure through the hole of the drawer connector section described above. Therefore, as a third embodiment of the present invention, the heat generated by the drive motor and the control board is sent to the fixing device 9 side through the hole of the drawer connector section by the above-described discharging side fan 11, and the fixing device 9 is fixed. Is exhausted together with the exhaust heat (i.e., exhausted through the flow path indicated by arrow A in FIG. 2).

By controlling the air flow in the copying machine as described above, it is possible to reduce the toner scattering inside and outside the copying machine even in the copying machine using the toner which is easily scattered.

Experiments carried out based on the above-mentioned embodiment will be described below. In the experiment, a copying machine having a digital optical system in which light from a laser diode is scanned by a polygon motor was used. In the experiment, two items of (1) confirmation of the state of toner scattering inside the machine and (2) confirmation of temperature rise inside the machine were examined with and without air flow control of the present invention.

When the air flow inside the machine is designed only for cooling inside the machine (when the air flow control of the present invention is not performed), the toner scattering is caused by the upper casing of the fixing unit, the main body structure side plate (transfer paper passing side), the fixing unit. End connector part Polygonal motor cooling duct It becomes severe at five places of the exhaust port to the inside and outside air. This is due to the flow mainly considering internal cooling.

The flow designed for the purpose of cooling the inside of the machine was aimed at the flow as shown in FIG. That is, the airflow from the toner scattering position is smoothly discharged to the outside.

In addition to this, the actual flow is as shown in FIG. 6, and the scattered toner adheres to the upper casing of the fixing unit by the flow B that has cooled the cleaning portion. The blowout of the front fan 10 causes the scattered toner to be drawn into the flow, so that the toner is attached to the sheet passing side of the main structure side plate (D, J). Besides, a flow occurs on the side opposite to the photoconductor of the fixing unit, and a flow on the inner side of the machine is generated (G, H, I). The rear side plate of the fixing unit has a hole because the joint portion of the drawer connector is located on the rear side of the rear plate. The flow on the back side of the fixing unit passes through the hole for the drawer connector (E) and does not pass through the hole for discharging heat provided above the fixing unit and the discharge unit, and the heat on the back side of the rear plate is reached. Is passing through the exhaust side fan from the hole for exhausting heat (F).

Therefore, the air flow control according to claim 1 is performed.
As a result, most of the toner scattering is limited to two points on the side surface of the toner scattering starting point of the partitioning member near the fixing unit added near the toner scattering starting point on the side plate of the main body structure. The upper casing of the fixing unit is partitioned by the partition member 13a, and the drawer connector portion of the fixing unit pulls the heat exhausted from the motor and the control board back to the paper-passing side of the fixing unit and then discharges it out of the machine (FIG. 2). Due to A) in the inside, the polygon motor cooling duct can suppress the toner adhesion by eliminating the attraction of the scattered toner due to the blowing. Further, by reducing the toner scattering at various places toward the external exhaust port, it is possible to reduce the scattered toner discharged to the outside of the machine.

However, the suppression of the flow inside the machine naturally affects the temperature inside the machine. In particular,
When the temperature of the photoconductor becomes high, problems such as sensitivity decrease become significant,
Also, if you do not exhaust the excess heat from the fixing unit,
This will cause the temperature of the entire machine to rise. In addition, the temperature rise of the control board placed across the structure from the paper passing part is
Machine runaway due to high temperature and temperature conditions of electric circuits cannot be satisfied.

Each part when the air flow control according to claim 1 of the present invention is performed is different from the case where the air flow control is not performed.
The following temperature rise is shown. Atmosphere on top of photoconductor: +3 to 5 deg Atmosphere on top of fixing unit (bottom of polygon motor): +8 deg Atmosphere of control board .. + 2deg When the airflow control according to claim 2 of the present invention as shown in FIG. 7 is performed, the temperature rise of each part is caused when the airflow control according to claims 1 and 2 is not performed. By comparison, the upper atmosphere of the photoconductor ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ +0.5 deg The upper atmosphere of the fixing unit (lower part of the polygon motor) ・ ・ ・ +6 deg Control board atmosphere・ ・ ・ ・ ・ ・ ・ ・ + 1deg, and it became possible to minimize the temperature rise of each part. As a result of confirming the copying operation of a large number of sheets under this condition, the toner scattering can be suppressed to the minimum, and the adverse effect due to the temperature rise does not occur.

[0028]

According to the present invention, since the toner flow can be suppressed by changing the flow path of the air flow in the copying machine, the toner scattering inside and outside the machine is limited to the vicinity of the toner scattering occurrence point. Therefore, it is possible to prevent the scattered toner from diffusing and adhering to the user operation unit, to obtain a clean inside / outside space of the machine, and to suppress an increase in the temperature inside the machine.

[Brief description of drawings]

FIG. 1 is a schematic sectional view of a copying machine showing an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing an airflow in the above embodiment.

FIG. 3 is a schematic sectional view of a copying machine showing another embodiment of the present invention.

FIG. 4 is a schematic perspective view showing an air flow in the other embodiment.

FIG. 5 is a schematic perspective view showing an air flow targeted by the present invention.

FIG. 6 is a schematic perspective view for explaining the difference between the target airflow and the actual airflow.

FIG. 7 is a schematic perspective view showing an airflow when a measure against temperature rise is taken.

[Explanation of symbols]

1 photoconductor 2 cleaning device 3 Static elimination lamp 4 charger 5 Digital optical system 6 developer 7 Transfer device 9 Fixing device 10 Suction side fan 11 Discharge side fan 13a, 13b partition plate

Continuation of the front page (56) Reference JP-A-5-224476 (JP, A) JP-A-3-116163 (JP, A) JP-A-5-27531 (JP, A) JP-A-5-197434 (JP , A) JP-A-4-32863 (JP, A) JP-A-62-44682 (JP, A) JP-A-62-169170 (JP, A) JP-A-64-59254 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) G03G 21/20 G03G 21/00 370-540 G03G 15/00 303 G03G 15/20-15/20 302

Claims (2)

(57) [Claims] 1. An image forming unit for forming a toner image on an image carrier,
An electrophotographic copying machine having a transfer means for transferring a toner image onto a transfer material, a cleaning means for collecting the toner image remaining on the image carrier, and a fixing means for fixing the toner image transferred on the transfer material by heat. In an outer cover of the fixing means, a cooling means for generating an air flow for cooling the image carrier, an exhaust heat means for discharging the air flow for cooling the image carrier and the heat generated by the fixing means to the outside of the machine. And a partition member that covers the outer cover to prevent the air flow between the fixing member and the transfer material passage portion from the image carrier to the fixing unit, and cools the image carrier. Shattered
Exhaust the air flow containing the ner along the outside of the partition member,
The heat generated by the fixing unit is discharged between the outer cover and the partition member toward the heat discharging unit to generate an air flow containing scattered toner that has cooled the image carrier and the generation of the fixing unit. A method for controlling an air flow in a copying machine, characterized in that the generated heat is diverted to the vicinity of the heat exhausting means. 2. A method of controlling air flow in a copying machine according to claim 1, wherein an exhaust heat path for guiding heat near the cleaning means from above the cleaning means to the exhaust heat means is secured.