JP2006084695A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image forming apparatus allowed to be quickly started without losing quality. <P>SOLUTION: In the image forming apparatus comprising: an environmental temperature detection means for detecting the installation environment of the image forming apparatus; a fixing device having a first heater; a heating power control means for controlling power supply to the heater; a fixing temperature detection means for detecting the surface temperature of a fixing roller built in the fixing device heated by the first heater; a power supply switch for carrying current to the first heater; and one or more second heaters other than the first heater and built in the fixing device: current carrying to the second heaters is controlled by the value of the environmental temperature detection means and the value of the fixing temperature detection means when the power supply switch is turned on. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an image forming apparatus such as a copying machine.

  The operation of the conventional copying machine will be described with reference to FIG.

  Reference numeral 1000 denotes a copying machine (image forming apparatus) main body.

  Reference numeral 1001 denotes an automatic document feeder for conveying a document to an exposure position, and 1002 denotes a document table glass as document placing means. The medium 30 is loaded on the paper feed cassette 15. The medium is usually paper, but there is a medium that can be a so-called OHP film such as an overhead projector. Reference numeral 300 denotes a medium loaded by a pickup roller. The paper is separated into one sheet by a separation paper feeding roller composed of 100 and 200, and sent to the conveyance path 19. Each of the conveyance rollers 114 is conveyed to the registration roller 113, and the registration roller 113 operates when other conditions such as an optical system are met. The latent image on the photosensitive drum 101 is transferred to a medium by the transfer unit 105, separated by the separation unit 106 so as not to be wound around the photosensitive drum, and sent to the conveyance belt 102. It is carried to the fixing roller 103 and the pressure roller 104 and fixed by the 103 and 104. As is, it is discharged out of the machine by the discharge rollers 111 and 112.

  When performing the double-sided operation, the flapper 122 does not discharge the apparatus to the outside but sends it to the double-sided conveyance unit below. When the reverse roller 123 rotates and feeds the medium in the A direction and reaches the reverse position 124, the reverse roller 123 rotates in the reverse direction and conveys the medium in the B direction. The medium is conveyed to the registration roller 113 through the duplex conveyance path 125.

  In the process in which the medium passes through the above-mentioned transport path, it passes through the sensors 121, 126, 127, 128, 129, 130, and 131, and always judges the current position by detecting the current position. At the same time, the registration roller 113 and the flapper 122 are controlled.

  Although not shown in the drawing, the photosensitive drum 101 includes a control device and a heater for maintaining the temperature of the photosensitive drum at the most preferable temperature for the photosensitive characteristics of the photosensitive drum. Improvements are being made.

  In the vicinity of the paper feed cassette 15, there is provided a cassette heater which is a heating means of the type for heating the paper loaded on the paper feed cassette 15, and the image forming apparatus is installed particularly in a high temperature and high humidity environment. In this case, it is possible to reduce the conveyance failure due to moisture absorption of the paper.

JP 2002-148996 A

  In the conventional image forming apparatus, for example, when the power is turned on in the morning in an office environment, the fixing device is sufficiently cooled down, so that the waiting time until the warm-up is completed increases when the copier is started up. The problem of end up occurs.

  In recent years, from the viewpoint of energy saving, functions such as a power saving mode and a sleep mode that automatically turn off the power when not used for a certain period of time have been installed, and the frequency of use has increased. Such a function is very effective from the viewpoint of energy saving, but it also has the inconvenience that it is difficult to use when trying to use it.

  For example, even a device that requires 4 seconds for the first copy is very unusable when the power is automatically turned off and the user starts up the copier and waits for another 5 minutes.

  Therefore, it is only necessary to supply enough power for the fixing device to start up quickly when the power is turned on. However, the upper limit is determined by the system configuration of the equipment because it is particularly necessary to keep it to 1500 W, which is the allowable value for general wiring in Japan. End up.

  In addition, the quality of the output image is very dependent on the environmental conditions in the image forming apparatus, and in order to stabilize the image, a cassette heater and a drum heater are necessary. Become. When a plurality of environmental heaters such as a drum heater for keeping the surface temperature of the photosensitive drum constant, a lens heater for the purpose of preventing condensation, and a cassette heater for preventing paper moisture absorption and stabilizing the conveyance system, for example, the drum heater 80W, When a plurality of lens heaters 20W and cassette heaters are used together, 60W is used, and the total calculation is 160W. Therefore, in order to suppress to 1500 W, 1340 W is the upper limit power consumption allowed for the entire system.

  Usually, in order to suppress to 1500 W, when approximately 600 W corresponding to the DC power source is subtracted, 800 to 900 W is distributed to the heater, and when it is 160 W, it actually increases to 20%.

  As a means for solving this problem, as disclosed in, for example, Japanese Patent Laid-Open No. 2002-148996, when the fixing heater is energized in order to reduce the consumption current at the peak time, 2. Description of the Related Art Copying apparatuses that perform control when energization is interrupted are known.

  In this publication, when the fixing heater and the oil heater are heated, the cassette heater and the drum heater are controlled to be interrupted. With such a configuration, a copying apparatus with reduced power consumption can be obtained.

  With such a configuration, it is effective to perform exclusive control in which the power supplied to the fixing and the power supplied to the various environmental heaters do not coexist. However, as described above, the quality of the output image largely depends on the environmental conditions. Therefore, in some cases, the quality is inferior.

  The purpose of the environmental heater is to assure quality after the power is turned on, and has a switch so that it can be energized at night. Therefore, if it is energized at night and kept at a predetermined internal temperature, it can be said that the above-mentioned exclusive control distributes the environmental heater to the fixing heater and can be said to be faster startup control. When the power is off, for example, when the power is turned on in the morning in the office environment as described above, the air conditioner is often ineffective, and the in-flight state is often the same as the environmental state as described above. In the morning environment, quality deterioration may occur, and it is not preferable to cut off the power supply to the environmental heater.

  On the other hand, if power is supplied to the environmental heater at a constant level, the power is automatically turned off and the machine is in the sleep state, as described above, in a normal office environment where the air conditioner is fully effective except in the morning. When starting up from the state, most of the energization to the environmental heater cannot be said to be very useful, and it is not only a mere invalid consumption of energy, but also an obstacle to starting up at high speed.

  SUMMARY An advantage of some aspects of the invention is that it provides an image forming apparatus that can be started up at high speed without impairing quality.

  In order to achieve the above object, the present invention provides an environmental temperature detection means for detecting an installation environment of an image forming apparatus, a fixing device having a first heating element, and a heating power for adjusting the supply of power to the heating element. Adjustment means, fixing temperature detection means for detecting the surface temperature of a fixing roller configured inside the fixing device heated by the first heating element, and a power switch for energizing the first heating element And one or a plurality of second heating elements other than the first heating element configured in the fixing device, wherein the environment when the power switch is turned on When the value of the temperature detecting means is a predetermined value and when the value of the fixing temperature detecting means is not more than a predetermined value, energization to the second heating element is prohibited.

  The second heating element has an energization selection means for energizing the second heating element, and the second heating element depends on the energization selection means state to the second heating element when the power switch is turned on. The image forming apparatus is characterized by controlling the energization of the environmental heater, and depending on the energization state of the environmental heater when the power is not turned on, the environmental heater is turned off at high speed or the quality of the environmental heater is turned on with priority. Is selected

  According to the present invention, when the temperature of the fixing device is sufficiently low and the environmental temperature does not affect the quality, the energization of the environmental heater can be controlled and a large amount of fixing power can be supplied. It is possible to start up. In addition, depending on the energization state of the environmental heater when the power is not turned on, the optimum state of whether the environmental heater is turned off at high speed or the environmental heater is turned on with priority on quality is selected.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a flowchart of an embodiment according to the present invention, FIG. 2 is an example of a fixing device, FIG. 3 is a drive circuit diagram of a heater arranged in the fixing device, and FIG. 4 is used in the present embodiment and the conventional example. An image forming apparatus.

  The fixing device will be described with reference to FIG.

  The fixing device shown in FIG. 2 includes a fixing roller 103 that comes into contact with the toner image on the front surface and a pressure roller 104 that comes into contact with the back surface side. In this fixing device 10, a recording material carrying an unfixed toner image on its surface is nipped and conveyed in a fixing nip between a fixing roller 103 and a pressure roller 104, and at that time, is subjected to pressure and heating to fix the toner. Is done.

  The fixing roller 103 is provided with a 1.2 mm thick silicone rubber layer 32 as an elastic layer on a hollow iron core 31 having a wall thickness of 0.7 mm and an outer diameter of 37.6 mm, and a toner release layer on the surface thereof. A 30 μm-thick PFA coating layer 33 is coated and formed to have a diameter of 40 mm. The toner release layer having a thickness of 30 μm is produced by electrostatically coating a PFA powder having an average particle diameter of 23 μm to a desired thickness and then baking it.

  On the other hand, the pressure roller 104 has a diameter of 30 mm by covering a solid rubber core 34 made of iron with a silicone rubber layer 35 having a thickness of 5 mm and a PFA tube layer 36 having a thickness of 50 μm on the surface thereof.

  In the fixing roller 103 described above, halogen heaters 37, 38, 39 are disposed in a hollow core 31 as heat generating means. The thermistor 41 is disposed so as to contact the fixing roller 103 to detect the temperature of the fixing roller 103. Based on this detected temperature, the control device 40 controls the halogen heaters 37, 38, 39 to keep the temperature of the fixing roller 103 constant. The fixing roller 103 and the pressure roller 104 are pressed with a total pressure of about 30 kg by a pressure mechanism (not shown). Further, at the time of fixing, the fixing roller 103 and the pressure roller 104 rotate to sandwich and convey the recording material.

  The form of the fixing device shown in the present embodiment is merely an example, and the configuration and dimensions of the fixing roller and the pressure roller, the materials used, and the like are appropriately determined according to the target recording material dimensions, toner particle materials, and the like. It is good to choose.

  Since the toner release layer of the fixing roller is produced by firing after electrostatic coating of fluororesin powder, if the thickness is less than 15 μm, coating with a uniform thickness becomes difficult. On the other hand, when the thickness exceeds 50 μm, although depending on the average particle diameter of the fluororesin powder to be used, in general, flexibility due to the structure obtained by firing the fluororesin powder is gradually not exhibited. As a result, the entire toner release layer is gradually hardened, and the function / action as an original elastic region cannot be exhibited. Therefore, the thickness of the toner release layer is more preferably selected to be at least 15 μm or more and not to exceed 50 μm.

  At that time, the average particle size of the fluororesin powder used is selected according to the average particle size of the toner particles. That is, as shown in this example, the average particle size of the fluororesin powder used is generally the toner particle. The average particle size is selected in the range of more than. In addition, if the average particle size of the fluororesin powder exceeds 30 μm, the method of firing after electrostatic coating will gradually make uniform coating difficult. Select fluororesin powder with an average particle size of 30 μm or less. It is desirable to do. In the apparatus configuration of the present embodiment, the average particle size of the toner particles used is selected to be 7 μm.

  In the present embodiment, by having three halogen heaters, a combination of a plurality of electric powers can be achieved, which corresponds to an increase or decrease in the electric power of the fixing heater described later.

  In addition, variable control of power increase / decrease can be performed even if a single halogen heater is used and control means using constant voltage control and electromagnetic induction heating is used.

FIG. 3 shows a constant voltage drive. AC is rectified and smoothed by D1 to D4 and C1, and then the TR1 is switched from the DC controller in the figure, so that a desired voltage is applied to the heater H1. By increasing or decreasing the applied voltage,
F1 (W) / F2 (W) = (V1 (V) / V2 (V)) ^1.54
The power fluctuates due to

For example, if a 100V / 500V heater is driven at 70V,
F1 (W) / 500 (W) = (70 (V) / 100 (V)) ^1.54
F1 = 288 (W)
It can be increased and decreased.

As an AC input unit for equipment, when used in a 100V power supply environment,
500 / 100V = 5A
From
288 / 100V = 2.88A
It becomes possible to reduce it.

  Although detailed description is omitted, since the electromagnetic induction heating method is also a high-frequency switching drive, it can be increased or decreased similarly.

  Next, the operation of the present embodiment will be described using the flowchart of FIG.

  When the power is turned on in 1001, it is detected in 1011 whether night energization is permitted. If energized at this time, the temperature inside the machine is maintained at a predetermined temperature by various environmental heaters and is not in a state that impairs quality. To do. If it is not energized at night, it is determined in 1021 whether or not the fixing device temperature T1 is equal to or lower than a predetermined temperature A. For example, if A is set to 50 ° C., it can be determined that it is in the morning when it is detected as 30 ° C. Conversely, if it is 100 ° C., it is a temperature region that rises quickly without giving priority to high-speed startup. There is no need to forcibly shut off the environmental heater that is not energized at night. Therefore, the environmental heater is turned on at 1061. In this case, however, it may be turned on as necessary depending on the temperature of T1.

  On the other hand, when T1 is low, it is the morning, so the required condition is determined at 1031 based on the environmental temperature T2. For example, t1 is 25 ° C. and t2 is 15 ° C.

  If it is t1 or more, first in Japan, it is a high-temperature and high-humidity environment, and the image quality is likely to deteriorate. Therefore, energization of the environmental heater becomes an essential condition and the process proceeds to 1061. In the case of t2, it is positioned under a low temperature environment. In this case, the image quality is also affected, but the start-up time will be longer, especially if the temperature is sufficiently low, and the presence or absence of the environmental heater with respect to the start-up time can be neglected. If no, go to 1061. In the present embodiment, the temperature is used, but it is more preferable if the temperature and humidity can be detected, and the temperature may be set according to the climate unique to each region.

  When T2 satisfies t1> T2> t2, the environmental heater is turned off at 1041, and the wattage setting of the fixing heater is increased at 1051.

  In this case, it is assumed that the fixing heater has an individual heater of 160 W in advance, and at least one of the halogen heaters 37, 38, 39 in FIG. 2 is 160 W. Alternatively, as described above, if other variable power increase / decrease control is possible, the power for 160 W is increased.

  When the warm-up is started in 1071 and completed in 1081, it is determined in 1091 whether or not the environmental heater is turned on. In this case, since it was forcibly turned off in the previous stage, it is permitted to turn on, not forcibly turned on. At 1101, a transition is made to standby.

3 is a flowchart of the present invention. 1 is a configuration diagram of a fixing device used in the present invention. It is a block diagram of the heating body drive circuit used for this invention. It is a detailed view of the main part of the present invention and a conventional image forming apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Photosensitive drum 102 Conveyor belt 103 Fixing roller 104 Pressure roller 1000 Main body 1002 Platen glass

Claims (4)

An environmental temperature detecting means for detecting an installation environment of the image forming apparatus, a fixing device having a first heating element, a heating power adjusting means for adjusting the supply of power to the heating element, and the first heating element. Fixing temperature detecting means for detecting the surface temperature of the fixing roller configured inside the heated fixing device, a power switch for energizing the first heating element, and the first device configured in the fixing device. An image forming apparatus having one or more second heating elements other than one heating element,
An image forming apparatus, wherein energization to the second heating element is controlled by a value of the environmental temperature detection unit and a value of the fixing temperature detection unit when the power switch is turned on.   Energization selection means for energizing the second heating element, and energization of the second heating element according to the state of energization selection means for the second heating element when the power switch is turned on 2. The image forming apparatus according to claim 1, wherein the image forming apparatus is controlled. An environmental temperature detecting means for detecting an installation environment of the image forming apparatus, a fixing device having a first heating element, a heating power adjusting means for adjusting the supply of power to the heating element, and the first heating element. Fixing temperature detecting means for detecting the surface temperature of the fixing roller configured inside the heated fixing device, a power switch for energizing the first heating element, and the first device configured in the fixing device. An image forming apparatus having one or more second heating elements other than one heating element,
The energization to the second heating element is controlled by the value of the environmental temperature detection means when the power switch is turned on and the value of the fixing temperature detection means, and the first heating element and the An image forming apparatus characterized in that power distribution is performed with priority given to the first heat generating element in the second heat generating element.   Energization selection means for energizing the second heating element, and energization of the second heating element according to the state of energization selection means for the second heating element when the power switch is turned on 4. The image forming apparatus according to claim 3, wherein the first heat generating element and the second heat generating element are distributed in such a manner that power is distributed with priority given to the first heat generating element.

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