JPH0379709B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording apparatus having means for fixing information on a recording material such as paper or sheets, and at least two different recording material feeding modes.

Conventionally, in recording devices such as copiers and printers,
Many of them have a function to feed sheets to be recorded in a cassette mode and a manual feed mode.

In general, in a recording device that has a manual feed mode, the fixing conditions such as the fixing temperature, amount of pressure, and conveyance speed in the fixing device can be adjusted to the extent that recording materials can be used, such as those with a diameter of several μm to 200 μm. Settings are made so that speed and fixing performance are satisfied.

In addition, some models use a special processing method for items such as postcards that are 0.3 mm or thicker and have a weight of 120 g/ ^m2 or more, but for items smaller than this, the general equipment described above is used. Usually, certain fixing conditions are set.

However, if the basic recording materials have a wide range like these, and the equipment is subject to the severe fixing conditions described above, the temperature inside the fixing device will rise due to high pressure in printers etc. that are on standby for a long time. Problems such as deformation of the rollers at the bottom are serious, and expensive parts, rollers, etc. must be replaced even in a much shorter period of time than the durability due to usage. In addition, conventionally, the fixing conditions for obtaining stable fixing performance with ordinary recording materials (relatively thin ones of several μm to 200 μm) are high temperature and high pressure;
If paper with a weight of 80 g/m ² or less is used, there is a problem in that the paper curls.

Furthermore, the recording material must be thin, ranging from several μm to 200 μm.
Those using transmitted light detection means or paper thickness detection means that detect thick objects larger than 200μm are prone to malfunction and cannot accurately detect objects, resulting in jams such as abnormal offset phenomena, curling, and wrapping. I end up. Further, this type of detection means cannot withstand long-term use, and malfunctions occur even when paper dust or toner adheres to the detection means, making it impractical and expensive.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an apparatus that solves the above-mentioned problems, improves the durability of the apparatus main body, reduces the need for replacing parts within the apparatus, and achieves appropriate fixing.

The basic technical idea of the present invention is that the recording material used in the device is supplied in different amounts depending on the paper feeding mode, and the fixing conditions are changed depending on the paper feeding mode. This reduces the load on the parts used in the device (e.g. rollers, separating claws, oil, photoconductor, etc.), and at the same time improves fixing performance regardless of the feeding mode of the recording material. be.

Another object of the present invention is that when a heating means is included in the fixing condition, it is possible to achieve energy saving, prevent temperature rise inside the machine, and extend the life of the apparatus.

In order to achieve the above object, the recording apparatus according to the present invention includes a manual paper feeder that is equipped with a detection sensor that detects the insertion of recording material and that manually feeds the recording material, and a cassette paper feeder that feeds the recording material from a cassette. and a fixing means for fixing an image on a recording material, characterized in that the recording apparatus has a switching means for switching fixing conditions so that fixing performance is increased based on the detection output of the detection sensor. .

The present invention will be described below with reference to the drawings.

FIG. 1 shows an example of an electrophotographic apparatus to which a fixing device according to the present invention can be applied. A description of the illustrated device will be added.

The photosensitive drum 9 has a photosensitive layer provided on a metal cylinder.
After being uniformly negatively charged by the primary charger 10,
Image exposure is performed by a light source 3 such as an LED or a laser. This causes a difference in surface potential on the surface of the photosensitive drum 9 depending on the light and dark pattern of the optical image, forming an electrostatic latent image with high contrast.
Next, due to frictional charging with the developing sleeve in the developing device 15, the latent image is developed with negatively charged toner and made visible. The development process is described in Japanese Patent Application Laid-Open No. 55-18656, Japanese Patent Application Laid-open No. 55-18657,
A developing method or apparatus based on the developing method or apparatus described in JP-A-55-18678 and JP-A-55-18679 was used.

Next, load the toner image into cassette 1 using the cassette mode.
A transfer charger 18 applies a positive charge to the back side of the recording material 17 such as paper supplied from the photosensitive drum 6, and the visible image on the photosensitive drum is transferred onto the recording material by the electrostatic attraction force. The toner image is thermally fixed by rollers 1 and 2.

The drum 9 is cleaned by the blade cleaning means 19 and reused.

The apparatus shown in FIG. 1 is also provided with a manual feed tray 20 for manual feed mode for manually feeding recording materials (cardboard, label paper, OHP paper, or other desired recording material) from outside the apparatus.

When the recording material is fed from the manual feed toilet, the manual feed detection sensor 21 detects the recording material being fed in the manual feed mode, and starts forming and developing an electrostatic latent image in the same manner as in the case of feeding paper from the cassette described above. Next, the recording material is conveyed from the manual feed toilet 20, stopped once by the register roller 22, and transferred to the transfer charger 1 in time with the toner image on the photoreceptor.
8 will be sent up. The following transfer and cleaning methods are the same as those for feeding paper from the cassette in the cassette mode described above. However, the fixing conditions (including at least one of fixing speed, fixing pressure, and fixing temperature) are controlled differently in manual feed mode than in cassette mode. Switching of the fixing conditions according to the mode will be described later.

FIG. 2 shows an example of a fixing device used to carry out the method of the present invention, and FIG. 3 shows a diagram of temperature settings and temperature changes of the fixing device.

In FIG. 2, reference numeral 1 denotes a fixing roll having a heater 5 built into a core metal 7 whose surface is coated with Teflon (trade name: DuPont Co., Ltd.) 6.
Reference numeral 2 denotes a pressure roller having a silicone rubber 8 having good mold release properties on its surface, a heat-resistant rubber 11 with high elasticity inside it, and a core metal 12 inside it. The heater 5 is controlled by detecting the temperature of the surface of the fixing roller 1 with a temperature sensing element 4 such as a thermistor. A recording material 24 carrying unfixed toner 23 is guided by a pre-fixing conveyance guide member 25, and heated between two rollers 1 and 2 to fix the toner onto the recording material. The recording material is peeled off by the separation claw 27 and discharged. Fixing roller 1
The toner adhering to the surface is cleaned by the felt 26. This felt 26 is impregnated with a release agent such as silicone oil, and also has the role of applying the release agent to the surface of the fixing roller.

An example of control using this specific configuration is as follows. When the main switch of the fixing roll 1 is turned on, the heater 5 starts to be energized, and the heater 5 is repeatedly turned on and off while repeatedly overshooting until the temperature reaches _T3 . When the temperature of the fixing roller 1 reaches _T3 , the wait state changes to the standby state. When the print signal is input at A, the set temperature of the fixing device is
T ₃ switches to higher T ₁ . Along with this, the heater 5 is turned on, and the surface temperature of the fixing roll rises, and after reaching a predetermined temperature _T1 at B, temperature control is performed before and after _T1 . After receiving the print ON signal,
Time to reach T ₁ , i.e. time from A to B t ₀
must be equal to or shorter than the time from the print ON signal until the leading edge of the transfer paper reaches the fixing device. That is, it is preferable that the surface of the fixing roll approaches or reaches the set temperature _T1 by the time the leading edge of the transfer material reaches the fixing device.

Also, when manually feeding, the detection sensor in the manual feed port detects that the transfer material has been inserted and sets the temperature of the fixing device higher than the temperature set when using a cassette _.
Switch to . As a result, the heater is turned on until the temperature of the surface of the fixing roll reaches _T2 , and reaches the predetermined temperature _T2 at C. At this time, from point A when the transfer material is inserted into the detection sensor of the manual feed port and the mode is switched from cassette mode to manual feed mode,
The time it takes for the fuser roll to reach the specified temperature _T2 ,
That is, the time t ₁ from A to C is longer than in the cassette mode because T ₁ <T ₂ . Therefore, in the manual feed mode, the fixing roller reaches approximately T ₂ within or at the same time after the transfer material is inserted into the detection sensor of the manual feed port and the transfer material reaches the fixing device after entering the manual feed mode. It is preferable.
Therefore, if there is enough power to input to the heater, the wattage of the heater can be increased to shorten the time required for the temperature to rise from T ₃ to T ₂ .
If there is not enough power to input to the heater, or if it is difficult to increase the wattage, it is necessary to extend the time it takes for the transfer material to reach the fixing device. Therefore, the manual feed detection sensor 2 of the manual feed port
It is necessary to lengthen the time from detecting the transfer material to actually entering the print mode, or by extending the pre-rotation time to lengthen the time until the transfer material reaches the fixing device.

As an example of practical numerical values of the present invention, a fixing roller having a configuration shown in FIG. 2 is used, in which a PTF layer of 25 μm is provided on an aluminum cylinder with a diameter of 2.5 mm and a thickness of 1.6 mm, and a pressure roller with a diameter of 10 mm. A 6mm thick Si sponge layer is coated on the stainless steel shaft of
Further, a 7 mm thick Si rubber layer was used as a surface layer. The roller length is 272mm for the fixing roller.
The pressure roller rubber part is 230mm. Also, the linear pressure between the fixing roller and the pressure roller is 0.25Kg/cm.
It is pressurized. A 600W heater is installed inside this fusing roller, and the temperature of the fusing roller during standby is
T ₃ is 150℃, temperature T ₁ in cassette mode is 160℃,
By setting the temperature T ₂ to 180° C. in the manual feeding mode, it has become possible to improve the fixing properties of cardboard and to extend the life of the fixing device.

The set temperature _T1 in cassette mode is approximately 20° lower than the set temperature of 180°C in conventional equipment, making it suitable for preventing temperature rise and thermal deterioration of rollers. Since the application of excessive heat to the material is reduced or eliminated, curling can be prevented and proper fixing can be achieved.

A control block diagram of this device is shown in FIG. Normally, when you press the print switch 28 in the cassette feeding mode, the controller 2
Step 9 switches the level of the comparator 30 from level A at standby temperature T ₃ to level B at temperature T ₁ (T ₁ >T ₃ ) in cassette feeding mode. The following description will be made assuming that the temperature sensor 4 has negative temperature characteristics. The output level S of the temperature sensor 4 is
When S>B, the temperature of the fixing roller is lower than the temperature _T1 of the cassette feeding mode, so the comparator 30 sends an L level signal to the controller 29.
Turn on the power supply 31 to energize the heater. When the output level S of the temperature sensor 4 is S<B, the fixing roller temperature is the temperature of the cassette paper feeding mode.
Since it is higher than T ₁ , the comparator 30 sends an H level signal to the controller 29 , which causes the controller 29 to turn off the power supply 31 and stop supplying electricity to the heater 32 .

On the other hand, the controller 29 starts a timer 33 at the same time as the print switch 28 is turned on, turns on/off a high-voltage power supply 35 used for latent image formation, development, and transfer, rotates the photosensitive drum, and transports the support material. The main motor 34 is controlled to start and stop, and to turn on and off image exposure.

Next, manual feed mode will be explained. When the recording material is detected by the manual feed sensor, the mode is set to manual feed, and the controller 29 sets the level of the comparator 30 to level A in the standby state.
to level C of the manual paper feed mode.
When the output level S of temperature sensor 4 is S>C, the temperature of the fixing roller is the temperature in manual paper feeding mode.
Since the temperature is lower than T ₂ , the heater 32 is energized and the fixing roller is heated to the temperature T ₂ .

On the other hand, when S<C, the temperature of the fixing roller is higher than temperature _T2 , and therefore the power supply to the heater 32 is stopped. There is a relationship of T ₂ > T ₁ > T ₃ between T ₁ , T ₂ , and T ₃ mentioned above, and when a 600W heater is used in this example, T ₁ to T ₂
Approximately 5 seconds were required for the temperature to rise to .

For this reason, it is preferable that the time it takes for the transfer material to reach the fixing device is 5 seconds longer in the case of manual feeding than in the case of cassette feeding. In this embodiment, a method was adopted in which the pre-rotation time until latent image formation was lengthened in the case of manual feeding. FIG. 5 shows a timing chart when feeding paper from a cassette and when feeding paper manually.

In the charts (a) and (b), in the manual feed mode (b), the timing of turning on the image exposure and development bias register roller clutches is delayed.

In the above embodiment, the flight printing time was 20 seconds in the cassette mode and 25 seconds in the manual feed mode. In the above timing chart (b), the ON timing of primary charging and transfer charging was delayed (c)
It goes without saying that other embodiments are also possible.

As yet another embodiment, if there is a sufficient distance from the transfer charger to the fixing device, the conveyance speed of the transfer material during this time may be changed. That is, during this period, the conveyance speed for manual paper feeding is made slower than the speed for cassette feeding.

As a result, the time from the start of printing until the paper enters the fixing device is longer in manual feed mode, which is practically preferable because the set temperature can be increased from T ₃ to T ₂ during this time.

Although the above embodiment has been explained using a printer as an example, the same applies to a copying machine having both cassette and manual feeding modes. Furthermore, in the above embodiment, the standby state temperature _T3 and the cassette mode temperature _T1 are set to _T3.
<T ₁ , but T ₃ and T ₁ may be the same.

In this way, the fusing temperature is lowered during the standby mode and cassette mode, which are often used on a daily basis, and the manual feed mode, which has a variety of types of recording materials, is used less frequently, so it is used only at this time (when the ) By increasing the temperature of the fixing device, it is possible to prevent roller deterioration and increase in temperature inside the machine, and improve fixing performance.

In the above embodiment, the heater was 600W, but an apparatus using two heaters of 600W and 400W is also possible. Low wattage during standby
Use only 400W heaters. In the case of cassette paper feeding mode, when raising the fixing roller temperature to the set temperature _T1 of the fixing conditions suitable for the cassette mode, turn off the power to the 400W heater and use a high wattage 600W heater. On the other hand, when switching to manual feed mode and increasing the fixing roller temperature to the set temperature _T2 , both the high wattage 600W and low wattage 400W heaters are energized.

A block diagram of this embodiment is shown in FIG.
Heaters A and B are placed inside the fixing roller 1 shown in FIG. 2, respectively, and have outputs of 600W and 400W, respectively. In the standby state before the print switch is turned on, the roller surface temperature is maintained at temperature _T3 by controlling the energization of low-output heater B.
When the print switch is turned on, it switches to cassette mode, heater B is turned off, and high output
600W heater A becomes energized. After the fixing roller temperature rises to the cassette mode set temperature _T1 , the temperature is adjusted to _T1 using a low output 400W heater B.

Also, in manual feed mode, manual feed sensor 2
The output from 1 switches to the manual feed mode, and the low output and high output heaters A and B are energized simultaneously from the standby state, and the temperature of the fixing roller is raised to the set temperature _T2 of the manual feed mode.
After this, the temperature is controlled at _T2 using a low output 400W heater B. In this way, it is preferable to use a low-output heater during temperature control in order to reduce ripples.

In both cassette mode and manual feed mode, as soon as printing is finished, the set temperature returns to _T3 and the machine enters standby mode.

By using two different types of heater output in this way, as in the above embodiment, the time t ₀ required for T ₃ → T ₁ and the time t required for T ₃ → T ₂ in FIG. ₁ is reduced, and control can be performed with only a single sequence in the cassette mode shown in FIG. 5a, making it possible to easily configure the circuit and reduce costs.

In addition, in the frequently used cassette mode,
If you heat up to T ₁ with 600W + 400W, there will be a lot of overshoot and the durability life of the roller will be shortened, but in this example, heating is done with a 600W heater, so there will be less overshoot than when heating with 1000W. , the life of the roller has been significantly extended.

Although the case where the fixing roller has two heaters has been described here, a plurality of heaters may be used.

Alternatively, you can set the heater's wattage to about 1200W and switch the input power between cassette mode and manual feed mode. In this case, the input power W ₁ during standby and the input power W ₂ in cassette mode are
Input power in manual feed mode W ₁ < W ₂ < W ₃ between W ₃
It is preferable that the relationship is as follows.

In the above embodiment, the set temperature of the fixing device was changed, but as another fixing condition variable means, it is also possible to change the amount of pressure applied between the fixing roller and the pressure roller. In this way, when only the amount of pressure is varied, it can also be applied to pressure fixing. An example is shown in FIG.

1 is a fixed fixing roller at the central position, 2 is a pressure roller, 37 is a fixed point pin, 38 is a compressed spring, 39 is an eccentric cam, and pin 42
Rotate around. Eccentric cam 39 during standby
is in contact with the arm 40 at a portion A. In this state, no pressure is applied between the pressure roller and the fixing roller.

Next, when the print switch is pressed in the cassette mode, the eccentric cam 39 begins to rotate in the direction of the arrow, comes into contact with the arm 40 at part B, and stops.
At this time, since the spring 38 is compressed and pushes up the arm 41, a pressure _P1 is applied between the fixing roller and the pressure roller.

On the other hand, in manual feed mode, manual feed sensor 2
When No. 1 detects a recording material, the eccentric cam 39 starts rotating in the direction of the arrow, comes into contact with the arm 40 at a portion C, and stops. In this state, a pressure P ₂ (>P ₁ ) is applied between the fixing roller and the pressure roller.

The pressurization during printing has been described above, but after printing is completed in any mode, the cam returns to position A and the pressure is released. As described above, by increasing the amount of pressure applied between the fixing roller and the pressure roller in the manual feed mode, it is possible to improve the fixing performance of thick paper, OHP paper, etc. In addition, since the time required to change the pressurization state is less than 0.5 seconds between the two modes, there is no need to change the image forming sequence between the two modes, simplifying the circuit and reducing costs.

In this example, the pressure is set low in the frequently used cassette mode, and high pressure is set in the manual feed mode, thereby improving durability and extending the life of the rollers. Furthermore, in this example, since the pressure is released during standby, the rubber material of the roller is less deformed and wrinkles can be prevented. Furthermore, it has the advantage of having a longer durable life.
The above embodiment is an example of preferable pressure control regardless of each mode of the manual cassette.

As another example, it is also possible to make the conveying speed of the fixing device slower in the manual feed mode than in the cassette mode. In other words, when thick paper or the like is manually fed, heating and/or pressure can be applied to the recording material by switching the driving means of the fixing rotary body such as the roller of the fixing device and slowing down at least the conveyance speed of the fixing roller, belt, etc. It lengthens the time and improves fixing properties. A block diagram of this embodiment is shown in FIG.

First, the cassette paper feeding mode will be explained. When the user turns on the print switch 28, the controller 29 determines that it is the cassette mode and switches the clutch 43 to "HIGH". In this state, the driving force of the main motor 34 is applied to the fixing device drive gear 44, and the fixing roller and pressure roller rotate at a peripheral speed _V1 . ( _V1 is a speed that is equal to or slightly slower than the circumferential speed of the photosensitive drum.) When the printing operation is completed, the main motor 34 stops rotating, and the fixing roller and pressure roller also stop.

On the other hand, in the manual feed mode, when the user inserts a recording material into the manual feed slot, the manual feed detection sensor 21 is activated and the controller switches to the manual feed mode. Clutch 43 is then switched LOW by a signal from the controller.
In this state, driving of the main motor 34 is started, and driving force is transmitted to the fixing device gear 44.
At this time, the circumferential speed _V2 of the fixing roller and the pressure roller is smaller than the circumferential speed _V1 in the above-mentioned cassette mode.

As mentioned above, by switching from the cassette mode to the manual feed mode, the conveyance speed in the fixing device is slowed down and the toner image is heated for a long time, thereby improving the fixation of the toner image on the thick paper that is manually fed. can.

Additionally, because this method completely fuses the toner image, it has been possible to eliminate paper stains and roller stains caused by offset toner, which conventionally occur when passing through thick paper. .

In the above example, when the conveying speed of the fixing device was set to 60 mm/sec in the cassette mode and 48 mm/sec during manual feeding, good fixing performance could be obtained. At this time, the time required to print one A4 size sheet is 20 seconds in cassette mode and 20 seconds in manual feed mode.
It took 21.2 seconds. The fixing device used has the same structure as the embodiment shown in FIG.

In the above embodiment, the setting temperature of the fixing device, the number of heaters used, the amount of pressure, and the fixing speed are controlled independently, but it is not necessarily necessary to control them individually, and a configuration in which a plurality of these are combined is also possible. It is possible. For example, a configuration in which the set temperature and the amount of pressurization are simultaneously changed according to the above-mentioned magnitude relationship is also possible. The pressurizing mechanism in this case may be of the same construction as shown in FIG. 7, and the circuit for switching the set temperature may be of the type shown in FIG. 4. In this method of simultaneously switching the set temperature and the amount of pressurization, it is only necessary to change the amount of change in the set temperature and the amount of change in the amount of pressurization only slightly.

In the above example, (1) the set temperatures are T ₁ = 170°C, T ₂ = 180°C, and T ₃ = 160°C under the condition of linear pressure P ₁ = 0.25Kg/cm;
(2) At T ₁ = T ₂ = T ₃ = 170℃, change the linear pressure to P ₁ = 0.24Kg/cm, P ₂ = 0.26Kg/cm,
The method was to switch to P ₃ = 0Kg/cm, but for example, linear pressure P ₁ = 0.24Kg/cm, P ₂ = 0.25Kg/cm, P ₃ =
0Kg/cm, T ₁ = 170℃, T ₂ = 175℃, T ₃ =
By switching to 160°C at the same time, it is possible to achieve an effect equal to or greater than the above-mentioned examples (1) and (2).
In particular, there is little margin for electricity that can be used for heaters.
Further, this is an effective configuration when there is little margin in the amount of pressure that can be varied depending on the roller rubber thickness of the fixing device used and the strength of the core metal. Although the set temperature and the amount of pressurization have been described above, a plurality of combinations among the conveyance speed, the amount of pressurization, and the set temperature are also possible.

By controlling the switching of fixing conditions according to the mode, we were able to achieve stable and reliable fixing and extend the lifespan of internal parts. In particular, by switching the fusing temperature, it is possible to lower the fusing setting temperature for plain paper that is frequently used and has relatively good fusing properties, and it is possible to extend the life of the fusing roller, which is especially made of rubber, in the fusing device. be. This extension of the life of the roller is an effect known in pressure fixing in which the amount of pressure applied is varied. In addition, by lowering the temperature of the fixing device in standby mode compared to the temperature during fixing, it is possible to extend the life of the fixing device, and also to save energy and reduce internal temperature rise during standby mode and cassette mode. I can do it.

In addition, the pressure between the pair of fixing rollers changes and is controlled depending on the mode such as cassette or manual feed, rather than depending on recording materials that are difficult to fix, such as thin plain paper and relatively thick cardboard. By changing the amount and lowering the set temperature of the fixing device, more stable fixing performance can be obtained, and in particular, it is possible to extend the life of the fixing roller using rubber.

Furthermore, by changing the fixing speed in the fixing device according to the mode change, the set temperature of the fixing device can be lowered.
Since toner can be fixed on cardboard, the life of the fixing device, especially the fixing roller using rubber, can be extended.

[Brief explanation of drawings]

FIG. 1 is a schematic side view showing a printer device used to carry out the present invention, FIG. 2 is a sectional side view of a fixing device according to the present invention, and FIG. 3 is a diagram showing temperature changes in the fixing device. Figure 4, Figure 6, Figure 8
The figures are block circuit diagrams for explaining the embodiments of the present invention, FIGS. 5a, 5b, and 5c are timing charts, and FIG. 7 is a cross section of the pressurizing mechanism of the embodiment of the present invention. It is a diagram. DESCRIPTION OF SYMBOLS 1... Fixing roller, 2... Pressure roller, 3... Light source, 4... Temperature sensor, 5... Heater, 9... Photosensitive drum, 10... Primary charger, 15... Developing unit, 18... Transfer charger, 19... Cleaner Unit 21... Manual feed detection sensor.

Claims (1)

[Scope of Claims] 1. A manual paper feeder that is equipped with a detection sensor that detects the insertion of a recording material and that manually feeds the recording material, and a cassette paper feeder that feeds the recording material from a cassette.
A recording apparatus comprising a fixing means for fixing an image on a recording material, the recording apparatus further comprising a switching means for switching fixing conditions so as to improve fixing performance based on the detection output of the detection sensor.