JPH064005A - Image forming device - Google Patents

Abstract

PURPOSE:To surely fix toner even when a long-size paper i.e., over a regular size is passed by controlling the turning-on frequency of plural heaters incorporated in a heating roller based on the discriminated result of the passing of the long-size paper. CONSTITUTION:A fixing device 108 is constituted of the heating roller 109 incorporating two heaters 101 and 102 inside and a pressure roller 110 nipping a transfer paper together with the roller 109. When the regular size transfer paper is passed, only the heater 101 is turned on and the roller 109 is warmed. However, when the long-size paper is passed, the passing of the long-size paper is recognized by a CPU 105 by depressing a switch SW1. Then, the heater 102 is also turned on in addition to the heater 101 and the roller 109 is warmed. Therefore, the roller 109 can be rapidly warmed by turning on two heaters even when the heat of the roller 109 is taken away somewhat by the long-size paper. Besides, the toner can be surely fixed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a fixing device composed of a heating roller and a pressure roller. More specifically, it is possible to pass a long paper having a size larger than a standard size. The present invention relates to an image forming apparatus.

[0002]

2. Description of the Related Art Generally, in an image forming apparatus having a fixing device composed of a heating roller and a pressure roller, the toner image transferred to the transfer paper is semi-melted by the heat of the heating roller in the fixing device and the transfer paper Permeate inside and fix.

On the other hand, in recent image forming apparatuses, long transfer paper (hereinafter referred to as long paper) has been demanded by a user who desires to use as the transfer paper a paper having a size larger than a standard size such as A4 size and B5 size. An apparatus capable of performing the paper passing (described as) is provided.

[0004]

However, according to the conventional image forming apparatus, a long paper having a size larger than the standard size (for example, a paper having a width dimension of A4 and a length of twice A3) is passed. In this case, since the heat drawn from the heating roller of the fixing device increases due to the passage of paper in proportion to the length of the long paper, the temperature of the heating roller decreases, and the toner cannot be reliably fixed. there were. In particular, when continuously feeding a long sheet of paper, there is a high risk of toner fixing failure.

The present invention has been made in view of the above, and an object of the present invention is to reliably fix toner even when a long paper is passed.

[0006]

In order to achieve the above object, the present invention provides a plurality of heaters incorporated in a heating roller, a discriminating means for discriminating the passage of long paper having a regular size or larger, and discriminating means. An image forming apparatus provided with a control means for controlling the number of lighting of a plurality of heaters based on the determination result of the means.

In order to achieve the above-mentioned object, the present invention further comprises an exhaust fan for preventing a temperature rise inside the image forming apparatus, a discriminating means for discriminating the passage of a long paper having a size larger than a standard size, and a discriminating means. An image forming apparatus including a control unit that controls the rotation amount of an exhaust fan based on the determination result of 1.

Further, in order to achieve the above object, the present invention determines a discriminating means for discriminating the passage of a long paper having a regular size or more, and discriminating that the discriminating means continuously conveys the long paper. Then, the image forming apparatus is provided with a control unit that controls the sheet feeding timing later than usual.

In order to achieve the above-mentioned object, the present invention determines that a long size paper having a size equal to or larger than a standard size is to be passed, and if the determination means determines that the long paper is to be passed, the drive is performed. (EN) An image forming apparatus provided with a control means for controlling the driving speed of each driving means such as a main motor of a system and a polygon motor of an optical system to be slower than usual so as to slow down the overall driving speed.

In order to achieve the above-mentioned object, the present invention further comprises a discriminating means for discriminating the passage of a long paper having a size equal to or larger than a standard size, and a first driving means for carrying the paper to a position immediately before the fixing device. And a second drive unit for driving the sheet conveyance after the fixing device, and when the determination unit determines that the long sheet is passed, the drive speed of the second drive unit is set to the drive speed of the first drive unit. The present invention provides an image forming apparatus including a control unit that controls the speed more slowly.

In order to achieve the above-mentioned object, the present invention further comprises a fixing device having a heater built in both a heating roller and a pressure roller, and a discriminating means for discriminating the passage of long-sized paper of a standard size or larger. The present invention provides an image forming apparatus provided with control means for turning on a heater of a pressure roller when the determination means determines that a long sheet is passed.

In order to achieve the above object, the present invention provides a first fixing device in which the heater is turned on at the same time when the power is turned on, a second fixing device in which the heater is normally turned off, and a fixed form. An image provided with a judging means for judging the passage of a long paper of a size or more, and a control means for turning on the heater of the second fixing device when the judging means judges that the long paper is passed. A forming apparatus is provided.

[0013]

In the image forming apparatus of the present invention (claim 1), when a long sheet is passed, the heater is turned on and the temperature of the heating roller is raised to perform fixing at a sufficient temperature.

Further, the image forming apparatus of the present invention (claim 2).
When passing a long sheet of paper, the rotation amount of the exhaust fan is reduced, the long sheet of paper is passed while the temperature inside the image forming apparatus is maintained at a high temperature, and the long sheet of paper is preheated. Give,
Fix at a sufficient temperature.

An image forming apparatus according to the present invention (claim 3).
When continuous paper is passed continuously, the paper feed timing is controlled to be slower than usual, and fixing is performed while the temperature of the heating roller has risen sufficiently.

Further, the image forming apparatus of the present invention (claim 4).
In the case of passing a long sheet of paper, the entire drive speed is controlled to be slow, so that the contact time between the heating roller and the long sheet of paper is lengthened and fixing is performed.

An image forming apparatus of the present invention (claim 5).
When feeding a long sheet of paper, the paper feeding drive after the fixing device is controlled to be slower than the paper feeding drive up to immediately before the fixing device, so that the contact time between the heating roller and the long paper is set longer. I do.

An image forming apparatus of the present invention (claim 6).
When passing a long sheet, the heater of the pressure roller is turned on, and heat is applied to the long sheet from both the heating roller and the pressure roller.

An image forming apparatus of the present invention (claim 7)
When passing a long sheet of paper, the heater of the second fixing device is turned on, and fixing is performed by both the first fixing device and the second fixing device.

[0020]

[Embodiment] With the above-mentioned constitution, the image forming apparatus of the present invention is applied to [Embodiment 1], [Embodiment 2], [Embodiment 3], [Embodiment 4], [Embodiment 5], [Embodiment 6]. ], [Seventh Embodiment] will be described in detail with reference to the drawings.

[Embodiment 1] FIG. 1A is a control block diagram of an image forming apparatus according to Embodiment 1, which is for detecting the heaters 101 and 102 for fixing processing and the temperatures of the heaters 101 and 102. Thermistors 103 and 104, a CPU 105 that controls lighting of the heaters, an AC power supply 106 that supplies power to the heaters 101 and 102, and ON / OFF of power supply to the heaters 101 and 102 based on a control signal from the CPU 105. It is composed of a switching SSR 107 (changeover switch). Incidentally, SW1 indicates a switch for designating the passage of the long paper when the long paper of a size other than the standard size is passed, and is provided on the operation panel (not shown) of the image forming apparatus. .

FIG. 1B shows the structure of the fixing device 108. As shown in the figure, the fixing device 108 includes a heating roller 109 having two heaters 101 and 102 built therein, and a pressure roller 11 that nips a transfer sheet together with the heating roller 109.
It consists of 0 and.

The operation of the above configuration will be described. Normally, when passing a fixed-size transfer sheet, only the heater 101 is turned on to heat the heating roller 109, but when passing a long-sized sheet other than the fixed-size sheet, the switch SW1 is pressed. As a result, the CPU 105 recognizes the passage of the long paper, turns on the heater 102 in addition to the heater 101, and heats the heating roller 109. Therefore, by heating the two heaters, the heating roller 109
Even if a certain amount of heat is removed, the heating roller 109 can be quickly warmed and the toner can be reliably fixed.

[Second Embodiment] In the image forming apparatus of the second embodiment, when a long sheet is recognized, the fan motor rotating the fan is stopped to prevent the temperature rise inside the image forming apparatus. I made the inside of the device a heating state,
In that process, the paper is passed.

FIG. 2 is a control block diagram of the image forming apparatus according to the second embodiment, which controls a fan motor 201 for driving a fan for preventing temperature rise, a driver 202 for rotating the fan motor 201, and a driver 202. CP to do
And U203. SW1 is a switch for designating the passage of long paper.

In the above structure, the CPU 203 normally rotates the fan motor 201 via the driver 202 when a fixed-size transfer sheet is passed. As a result, the heat inside the image forming apparatus is exhausted and the temperature rise is prevented. On the other hand, when a long paper other than the standard size is passed, the CPU SW2
03 recognizes the passage of the long paper, and stops the fan motor 201 via the driver 202. Therefore, heat is not exhausted from the inside of the image forming apparatus, and the inside of the apparatus is in a heated state. Therefore, when the temperature inside the apparatus rises while the rotation of the fan motor 201 is stopped, the temperature of the entire apparatus rises and the long paper is given a certain amount of heat even before the fixing process. Therefore, a heating roller (not shown) is provided. ), It is possible to avoid taking heat more than necessary, and it is possible to reliably fix the toner.

Further, in the second embodiment, the fan motor 201
The driving of the fan motor 201 is stopped, but for example, as shown by a broken line in FIG. 2, a driver 204 equipped with a resistor R for reducing the output current is used to suppress the current supplied to the fan motor 201 to reduce the fan current. The number of rotations of the motor 201 may be reduced.

[Third Embodiment] In the image forming apparatus of the third embodiment, when the long paper is continuously fed, the paper feed timing is controlled to be slower than usual, and the temperature of the heating roller is sufficiently raised. The fixing is carried out in this state.

FIG. 3 is a control block diagram of the image forming apparatus according to the third embodiment. A paper feed roller 402 (details will be described later) for feeding transfer paper from a paper feed unit 401 (not shown) (see FIG. 4). And a clutch 301 for driving
01 is operated, and a CPU 303 controlling the driver 302. In addition, SW1
Indicates a switch for designating long paper passage.

FIG. 4 is a schematic block diagram of the image forming apparatus 400 of the third embodiment. As shown in the figure, inside the image forming apparatus 400, a paper feed unit 401 for feeding a transfer paper such as a fixed size and a long paper, a paper feed roller 402 for feeding the transfer paper from the paper feed unit 401, and a fixing device 403. Are arranged.

In the above structure, when a long paper other than the standard size is passed, the switch SW1 is pressed to cause the CPU 303 to recognize the passage of the long paper. At this time,
If the long sheet is continuously fed, the driving timing of the clutch 301 is delayed via the driver 302 as compared with the normal timing to control the clutch 301 at the timing. As a result, the clutch 301
Is turned on later than the normal timing, the paper feed roller 402 is rotated, and the transfer paper conveyance is started. In other words, the long paper is passed with a large interval between the paper feeds. Therefore, even if the lengthy paper is once passed and the heat quantity of the heating roller (not shown) is taken away, the following temperature should be provided with a margin to recover the fixing temperature during continuous feeding of the long paper. By passing the paper, the toner can be reliably fixed at a sufficient temperature.

[Fourth Embodiment] In the image forming apparatus of the fourth embodiment, when a long sheet is passed, fixing is performed while the temperature of the heating roller is sufficiently increased by controlling the entire driving speed to be slow. It is something to do.

FIG. 5 is a control block diagram of the image forming apparatus of the fourth embodiment, in which a drive system main motor 501, an optical system polygon motor 502, and a driver 50 for driving the main motor 501 and the polygon motor 502, respectively.
3, 504, programmable counters 505 and 506 that change the division ratio of the reference clock 508, and a CPU 507 that controls the entire system. Reference numeral 508 indicates a reference clock, and SW1 indicates a switch for designating the passage of long paper.

In the above configuration, when a long paper of a size other than the standard size is to be passed, the CPU 507 recognizes the passage of the long paper by pressing the switch SW1. CPU
507 changes the division ratio of the reference clock 508 via the programmable counters 505 and 506 to reduce the rotation speeds of the main motor 501 and the polygon motor 502. As a result, the overall drive speed becomes slower, and the paper passing speed for long paper also becomes slower.

Generally, the conditions necessary for fixing the toner are three factors of temperature, time and pressure, but in the fourth embodiment, the paper passing speed of the long paper is slowed (that is, the paper passing time is lengthened). )
As a result, even if the temperature of the heating roller has dropped slightly,
The toner is fixed over time, and the toner is surely fixed.

[Embodiment 5] In the image forming apparatus of Embodiment 5, in the case of passing a long sheet of paper, the paper conveyance drive after the fixing device is controlled to be slower than the paper conveyance drive immediately before the fixing device. The fixing is performed by increasing the contact time between the heating roller and the long paper.

FIG. 6 is a control block diagram of the image forming apparatus of the fifth embodiment. The image forming apparatus according to the fifth exemplary embodiment includes a drive system motor 6 that drives the sheet conveyance until just before the fixing device 609.
01 and a drive system motor 602 for driving the sheet conveyance after the fixing device. In the figure, 603,6
Reference numeral 04 denotes drivers 603 and 604 that drive the drive system motors 601 and 602, respectively, reference numerals 605 and 606 denote programmable counters that change the division ratio of the reference clock 608, and 607 denotes a CPU that performs overall control.
SW1 indicates a switch for designating the passage of long paper.

In the above structure, when a long paper of a size other than the standard size is passed, the switch SW1 is pressed and the CPU 607 recognizes the passage of the long paper. CPU
Reference numeral 607 changes the frequency division ratio of the reference clock 608 via the programmable counter 606 to reduce the rotation speed of the drive system motor 602 after the fixing device. As a result, the sheet conveyance speed before the fixing device 609 does not change, and the sheet conveyance speed after the fixing device 609 becomes slow. Therefore, by slowing down the sheet-passing speed of the long paper in the fixing device 609, it is possible to fix the toner over a certain period of time and reliably fix the toner even if the temperature of the heating roller is slightly lowered.

Since the sheet conveying speed before the fixing device 609 does not change and the sheet conveying speed after the fixing device 609 becomes slow, as shown in FIG.
A certain amount of space 610 is provided in front of 09, and the long paper is slackened between the spaces to prevent paper jams and the like.

[Sixth Embodiment] An image forming apparatus according to a sixth embodiment is
When passing a long sheet of paper, the heater of the pressure roller is turned on, and heat is applied to the long sheet of paper from both the heating roller and the pressure roller. FIG. 7B shows the configuration of the fixing device 708, and the fixing device 708 includes the heater 701 as shown.
And a pressure roller 710 having a heater 702 incorporated therein.

FIG. 7A is a control block diagram of the image forming apparatus according to the sixth embodiment, in which a heater 701 built in a heating roller 709 and a pressure roller 702 built in a pressure roller 710.
, Thermistors 703 and 704 for detecting the temperatures of the heaters 701 and 702, and a CP for controlling the lighting of the heaters
U707 and A for supplying electric power to the heaters 701 and 702
It is composed of a C power source 706 and an SSR 707 (changeover switch) that switches ON / OFF of power supply to the heaters 701 and 702 based on a control signal from the CPU 705. Incidentally, SW1 indicates a switch for designating the passage of the long paper when the long paper other than the standard size is passed.

The operation of the above configuration will be described. Normally, when passing a fixed-size transfer sheet, only the heater 701 is turned on to heat the heating roller 709. On the other hand, when passing a long paper other than the standard size, the CPU 705 recognizes the passage of the long paper by pressing the switch SW1, and in addition to the heater 701, the heater 7
02 is also turned on and the pressure roller 710 is heated in addition to the heating roller 709. Therefore, by turning on two heaters, even if some heat is taken by the long paper, both heaters 70
With 1,702, the temperature can be quickly raised and the toner can be reliably fixed.

[Embodiment 7] The image forming apparatus of Embodiment 7 is
When passing a long sheet of paper, turn on the heater of the second fixing device.
In this state, the fixing is performed by both the first fixing device and the second fixing device. FIG. 8B shows the first fixing device 80.
8 and the second fixing device 809 are shown. As shown in the figure, the first fixing device 808 is arranged on the upstream side of the sheet conveying path, and subsequently, the second fixing device 809 is arranged. Here, the heater of the first fixing device 808 is turned on when the power is turned on, and the heater of the second fixing device 809 is normally turned off.

FIG. 8A is a control block diagram of the image forming apparatus according to the seventh embodiment, in which a heater 801 incorporated in the first fixing device 808 and an 802 incorporated in the second fixing device 809. , Thermistors 803 and 804 for detecting the temperatures of the heaters 801 and 802, the CPU 807 that controls the lighting of the heaters, the AC power supply 806 that supplies power to the heaters 801 and 802, and the heaters based on control signals from the CPU 805. Turn on the power to 801 and 802
It is composed of an SSR 807 (selection switch) for switching off. Incidentally, SW1 indicates a switch for designating the passage of the long paper when the long paper other than the standard size is passed.

The operation of the above configuration will be described. Normally, when a fixed-size transfer sheet is passed, only the heater 801 of the first fixing device 808 is turned on to perform the fixing process. On the other hand, when passing a long paper other than the standard size, press switch SW1 to press C
The PU 805 recognizes the passage of the long paper, and the first fixing device 8
The heater 801 of the second fixing device 809 is also turned on in addition to the heater 801 of the first fixing device 808.
The fixing process is continuously performed by both the fixing device 809 and the fixing device 809.
Therefore, the long paper is fixed by the first fixing device 808 and then further fixed by the second fixing device 809. Even if the first fixing device 808 loses heat to the long paper to some extent, The second fixing device 809 can surely fix the toner.

[0046]

As described above, in the image forming apparatus of the present invention, the plurality of heaters incorporated in the heating roller, the discriminating means for discriminating the passage of the long-sized paper of the standard size or more, and the discrimination of the discriminating means. Since the control means for controlling the number of lighting of the plurality of heaters is provided on the basis of the result, the toner can be reliably fixed even when the long paper is passed.

In the image forming apparatus of the present invention, the exhaust fan for preventing the temperature rise inside the image forming apparatus, the discriminating means for discriminating the passage of the long paper having the size larger than the standard size, and the discriminating result of the discriminating means are used. Based on the above, since the control means for controlling the rotation amount of the exhaust fan is provided, even when a long paper is passed,
It is possible to reliably fix the toner.

In the image forming apparatus of the present invention, when it is determined that the determination means determines the passage of the long paper of the standard size or more and the determination means determines that the long paper is continuously passed, it is more than usual. Also has a control means for controlling the paper feed timing late, so that the toner can be reliably fixed even when a long paper is passed.

Further, in the image forming apparatus of the present invention, the discriminating means for discriminating the passage of the long-sized paper having a size larger than the standard size and the main motor of the drive system when the discriminating means discriminates the passage of the long-sized paper. And a control means for controlling the driving speed of each driving means such as a polygon motor of the optical system to be slower than usual so as to control the entire driving speed slower. Can be reliably performed.

Further, the image forming apparatus of the present invention comprises a discriminating means for discriminating the passage of a long paper having a size equal to or larger than the standard size, a first driving means for carrying the sheet to the position immediately before the fixing device, and the fixing device. When the second driving unit that performs the subsequent sheet conveying drive and the determination unit determine that the long sheet is passed, the driving speed of the second driving unit is controlled to be slower than the driving speed of the first driving unit. Since the control means is provided, the toner can be reliably fixed even when a long sheet is passed.

Further, the image forming apparatus of the present invention comprises a fixing device having heaters built in both the heating roller and the pressure roller,
A discriminating means for discriminating the passage of a long paper having a size larger than the standard size,
When the discriminating means discriminates that the long paper is passed, the control means for turning on the heater of the pressure roller is provided. Therefore, even when the long paper is passed, the toner can be surely fixed. .

In the image forming apparatus of the present invention, the first fixing device in which the heater is turned on at the same time when the power is turned on, the second fixing device in which the heater is normally turned off, and the length longer than the standard size. Since the judgment means for judging the passage of the lengthy paper and the control means for turning on the heater of the second fixing device when the judgment means determines that the lengthy paper is passed, Even when the paper is passed, the toner can be reliably fixed.

[Brief description of drawings]

FIG. 1A is a control block diagram of an image forming apparatus according to a first embodiment, and FIG. 1B is an explanatory diagram showing a configuration of a fixing device.

FIG. 2 is a control block diagram of an image forming apparatus according to a second embodiment.

FIG. 3 is a control block diagram of an image forming apparatus according to a third embodiment.

FIG. 4 is a schematic configuration diagram of an image forming apparatus according to a third embodiment.

FIG. 5 is a control block diagram of an image forming apparatus according to a fourth exemplary embodiment.

FIG. 6A is a control block diagram of the image forming apparatus according to the fifth embodiment, and FIG. 6B is an explanatory diagram showing a space in front of the fixing device.

FIG. 7A is a control block diagram of an image forming apparatus according to a sixth embodiment, and FIG. 7B is an explanatory diagram showing a configuration of a fixing device.

FIG. 8A is a control block diagram of an image forming apparatus according to a seventh embodiment, and FIG. 8B is a first fixing device and a second fixing device.
It is an explanatory view showing the arrangement of the fixing device.

[Explanation of symbols]

101 102 Heater 105 CPU 108 Fixing Device 109 Heating Roller 110 Pressure Roller 201 Fan Motor 203 CP
U 301 Clutch 303 CP
U 501 Main motor 502 Polygon motor 507 CPU 601 602 Drive system motor 607 CPU 701 702 Heater 705 CPU 709 Heating roller 710 Pressure roller 801 802 Heater 805 CPU 808 First fixing device 809 Second
Fixing device

Claims (7)

[Claims] 1. An image forming apparatus having a fixing device composed of a heating roller and a pressure roller, wherein a plurality of heaters incorporated in the heating roller and a discriminating means for discriminating the passage of long paper of a standard size or more. An image forming apparatus comprising: a control unit configured to control the number of lighting of the plurality of heaters based on a determination result of the determination unit. 2. An image forming apparatus having a fixing device composed of a heating roller and a pressure roller, and discriminating between an exhaust fan for preventing a temperature rise inside the image forming apparatus and the passage of long-sized paper of a standard size or more. An image forming apparatus comprising: a determination unit and a control unit that controls a rotation amount of the exhaust fan based on a determination result of the determination unit. 3. An image forming apparatus having a fixing device composed of a heating roller and a pressure roller, and a discriminating means for discriminating the passage of a long paper of a regular size or larger, and the discriminating means continuously connecting the long paper. An image forming apparatus comprising: a control unit that controls the sheet feeding timing later than usual when it is determined that the sheet is passed. 4. An image forming apparatus having a fixing device composed of a heating roller and a pressure roller, a discriminating means for discriminating the passage of a long paper having a size larger than a standard size, and the discriminating means passing the long paper. If it is determined that the drive speed is lower than the normal speed, the control means for controlling the drive speed of the main motor of the drive system and the polygon motor of the optical system to be slower than usual is provided. Image forming apparatus. 5. An image forming apparatus having a fixing device composed of a heating roller and a pressure roller, a judging means for judging the passage of a long paper having a size equal to or more than a standard size, and a sheet conveying drive immediately before the fixing device. When the discriminating means discriminates that a long sheet of paper is passed, the second driving means is driven. An image forming apparatus comprising: a control unit that controls the speed to be slower than the driving speed of the first driving unit. 6. An image forming apparatus having a fixing device composed of a heating roller and a pressure roller, wherein the fixing device has a heater incorporated in both the heating roller and the pressure roller, and a long-size paper sheet having a size larger than a standard size. An image forming apparatus, comprising: a determination unit that determines whether the pressure roller is turned on when the determination unit determines that a long sheet is passed. 7. An image forming apparatus having a fixing device composed of a heating roller and a pressure roller, wherein a first fixing device in which a heater is turned on upon power-on and a second fixing device in which a heater is normally turned off. Fixing device, a determining means for determining whether or not long-sized paper of a standard size or more is passed, and when the determining means determines that the long-sized paper is passed, the heater of the second fixing device is turned on. An image forming apparatus, comprising: