JPH04101960A - Paper conveyor device - Google Patents

Abstract

PURPOSE:To aim at space saving in an image forming device through making a guide means compact by providing an air blowout hole on a space facing the guide means. CONSTITUTION:An air blowout hole 11-2 is provided on a space facing a guide means 40. A fan 11 is then operated, and a transfer paper sheet S is conveyed while blowing air from the image forming face side of the transfer paper sheet S by the air flow flowing out of this blowout hole 11-2.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a paper conveyance device that can be applied to image forming apparatuses including facsimile machines and printers.

(Conventional technology) A transfer paper with a toner image transferred from an image carrier.

There is an image forming apparatus that transports an image to a fixing device via a guide means (see, for example, Japanese Patent Laid-Open No. 63-93343).

For example, referring to FIGS. 7 and 8, the paper conveyance device of a copying machine will be explained. As shown by broken lines, the transfer paper is transferred to the registration roller 1, the transfer charger 2, the separation charger 3, the guide means 4, and the fixing device 5. They are sent in order.

In other words, after being charged by the main charger 10, the electrostatic latent image carried on the photoreceptor 6 as an image carrier by exposure to exposure light is
A toner image is formed by the developing means 7, and this toner image is transferred onto a transfer paper at a transfer section where a transfer charger 2 is disposed. On the other hand, the photoreceptor 6 after the transfer is cleaned by a cleaning device 8 and used for the next image formation.

The transfer paper, on which the toner image has been transferred, is attracted to a conveyor belt 4-1, which serves as one of the guide means 4, and is sent toward the fixing device 5 as the belt rotates.

In order to obtain stable conveyance performance even for irregularly shaped paper such as curled paper, a belt with a large number of openings is provided as a means for sufficiently adsorbing the transfer paper to the belt 4-1. A vacuum tank installed inside the vacuum tank and a vacuum fan 4 that creates negative pressure in the vacuum tank.
A suction means such as -2 is provided. The vacuum fan 4-2 is provided on the outside of the main body side plate 7.

By providing such a guide means 4, even irregularly shaped transfer paper such as curled paper can be sufficiently attracted to the belt 4-1, thereby ensuring reliable conveyance.

(Problems to be Solved by the Invention) In the conventional paper conveying device 4, in order to secure installation space for the guide means 4 including the belt 4-1, vacuum fan 4-2, vacuum tank 4-3, etc., the entire copying machine is There are restrictions on miniaturization, and there are also problems from the perspective of space and energy saving, such as the need for a powerful vacuum fan and driving force to attract irregularly shaped transfer paper such as curled paper to the belt. SUMMARY OF THE INVENTION It is an object of the present invention to provide a paper conveyance device that can save space in an image forming apparatus by downsizing the guide means and can perform sufficient conveyance with less power than conventional ones.

(Means for Solving the Problems) In order to achieve the above object, in the paper conveying device of the present invention, an air outlet is provided on the space facing the guide means, and the air flow flowing out from the air outlet guides the paper conveying device. The transfer paper was conveyed while blowing air from the image forming surface side of the transfer paper on the means.

In this case, it is preferable that the amount of air blown can be changed according to the single paper pass mode.

Furthermore, it is effective to configure the guide means with a porous member that allows ventilation.

(Function) The transfer paper is conveyed while being pressed against the guide means by the wind pressure of the air flow sent out from the blower fan.

(Example) In this example, as shown in FIG. 1, a blower fan 11 is provided in place of the conventional vacuum fan.

The outlet side of this blower fan 11 is branched, and one side is guided to a duct 11-1, and one is guided to an air outlet 11-2 above the guide means 40 along the cleaning device 8. The guide means 4o is constituted by a porous member in which a large number of elongated openings are regularly formed along the feeding direction A of the transfer paper S, as shown in FIG. 2 or 3. The guide means may be constructed in the form of a wire, or may be constructed with ribs arranged in parallel.

A duct 11-3 is provided on the back side of the guide means 40, facing the air outlet 11-2, and this duct communicates with the outside of the copying machine via an ozone filter 12.

This duct 11-3 is guided by a guide 13 and can freely move in and out in the direction penetrating the page. For example, in a state where it is pulled out to the front side, the guide means 4o is rotated together with the charger 2.3 etc. using the shaft 40-1 as a fulcrum. The machine can be moved to handle maintenance such as removing jammed paper.

Note that another branched duct 11-4 on the outlet side of the blower fan 11 is guided to the main charger 1o.

The minimum size of the transfer paper S used in this copying machine is assumed to be larger than the length from the separation charger 3 to the nip portion of the fixing device 5.

Once the transfer paper S has been transferred, it is separated from the photoreceptor 6 by the separation charger 3, and when it is further fed, its leading edge usually curls upward as shown by the two-dot chain line in FIG. 1, impairing its conveyance. . However, as in this example, the airflow from the blower fan 11 is directed from the outlet 11-2 to the guide means 40.
If the curl is caused to occur toward the upper surface of the transfer paper, the curl is blown onto the image forming surface, which is the upper surface of the transfer paper, and the curl is corrected downward by the wind pressure and follows the guide means 40.

Under such a state, the rear end of the transfer paper S is still attracted to the photoreceptor 6, so the transfer paper S is fed out as the photoreceptor 6 rotates in the direction of the arrow, and eventually moves along the guide means 40. The leading end is held in the nip portion of the fixing device 5.

The airflow that has passed through the guide means 40 is guided to the duct 11-3, passes through the ozone filter 12, and is discharged to the outside of the machine.

The air volume blown out from the air outlet 11-2 is approximately 1.2 m/sec to 2.4 m/sec when the transfer paper is plain paper, so that the image before fixing is not disturbed and the paper is aligned with the guide means. It was also suitable for

The amount of air blown from the air outlet 11-2 may be changed depending on the paper passing mode. The means is to switch the driving power of the blower motor M in two steps by CPU control as shown in FIG. 4, and to change the fan high speed state and
Switch between fan low speed state.

When the paper feeding mode is double-sided copying, the paper passes through the fixing device more times, so the degree of curl is generally greater than when the paper feeding mode is single-sided copying. ” and so on.

In the determination step of "vertical conveyance detection ON" in FIG. 5, for example, in the double-sided copying machine shown in FIG. , is turned on when the transfer paper leaving the reversing means 14 is detected by the vertical conveyance detection device 15 provided in the middle of the vertical conveyance path. In other words, the fan speed is increased only when vertical conveyance detection is performed.

Note that in FIG. 6, a paper discharge detection device 16 provided at the exit of the fixing device 5 is for detecting the necessity of blowing air to the air outlet 11-2. is stopped (see Figure 5).

In FIG. 6, reference numeral 17 indicates an automatic document feeder, reference numeral 18 indicates an original table glass, reference numeral 19 indicates an imaging lens, and reference numeral 20 indicates a paper feeding section.

On each side of FIGS. 1 and 6, the duct from the blower fan 11 is guided along the cleaning device 8,
Since the air flow within the duct exerts a cooling effect, it is possible to prevent the waste toner in the cleaning device 8 from being welded by heat from the fixing device.

As described above, in this example, unlike the prior art, a belt is not used as a guide means, so that costs can be reduced, the distance between the photoreceptor and the fixing device can be shortened, and the machine can be made more compact.

Additionally, the shortened conveyance path has made it possible to increase the copying speed.

As for conveyance stability for irregularly shaped paper, sufficient performance can be obtained even with a low air volume using a blower fan.

Furthermore, a fixing device 5 and a cleaning device 8 that generate heat
Since the structure is such that an air duct is disposed between the cleaning device and the cleaning device, there is an advantage in that it can block heat, and in particular, it can prevent stray toner inside the cleaning device from being thermally welded.

Ozone generated on the photoreceptor is also removed through the ozone filter along with the air blowing.

Furthermore, when the air flow rate is increased or decreased depending on the paper passing mode, unnecessary power consumption can be suppressed and energy can be saved.

(Effects of the Invention) According to the present invention, it is possible to save space in the image forming apparatus by downsizing the guide means, and at the same time, it is possible to obtain sufficiently stable transfer paper conveyance performance even with small power.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the paper conveying device according to the present invention, FIGS. 2 and 3 are perspective views each illustrating a specific example of the guide means, FIG. 4 is an explanatory diagram of the air flow rate switching means, and FIG. FIG. 6 is a flowchart for the switching control, FIG. 6 is a detailed explanation of the present invention in a double-sided copying machine, and FIGS. 7 and 8 are illustrations of the prior art. 11...Blower fan, 11-2...Air outlet, 4o.
...Guidance means, S...transfer paper. (1 other person) Figure A Sword diagram Figure Z Figure Side Wa diagram

Claims (1)

[Scope of Claims] 1. In an image forming apparatus that transports a transfer sheet onto which a toner image has been transferred from an image carrier to a fixing device via a guide means, an air outlet is provided in a space facing the guide means. and a paper conveyance device that conveys the transfer paper while blowing air from the image forming surface side of the transfer paper on the guide means using an air flow flowing out from the blow-off port. 2. The paper conveying device according to claim 1, wherein the air volume can be changed according to the paper passing mode. 3. The paper conveying device according to claim 1, wherein the guide means is constituted by a porous member that allows ventilation.