JP6980442B2 - Image forming device - Google Patents

Description

The present invention, electronic photographic method by the copying machine, a printer, an image forming apparatus such as a facsimile.

Conventionally, the fixing device applied to the above-mentioned electrophotographic copying machine, printer, and other image forming devices adopts a contact heating type thermal roller fixing method with good thermal efficiency and safety, and an energy-saving type film heating method. There is.

The above-mentioned film heating type fixing device is, for example, JP-A-63-313182, JP-A-2-157878, JP-A-4-44075 to JP-A-4-44083, JP-A-4-204980. As described in JP-A-4-204984, a heat-resistant film (hereinafter referred to as a fixing film or film) which is a rotating body for heating is referred to as a rotating body for pressurization (hereinafter referred to as a pressurizing roller). ), The film is slid and conveyed in close contact with the heater, and a recording paper carrying an unfixed toner image is introduced into the fixing nip formed by the heater and the pressure roller with the fixing film sandwiched between them. The unfixed toner image is fixed on the recording paper by the heat from the heating body applied through the fixing film and the pressing force of the fixing nip portion.

Further, in this type of film heating type fixing device, the fixing film is driven by providing a drive roller on the inner peripheral surface of the film and driving the film while applying tension, and the film is loosely fitted to the film guide. , A method of driving a film to rotate with respect to a rotating body for pressurization by driving a rotating body for pressurization is known, but in recent years, since the number of parts is small, the latter drive method for pressurizing rotating body is used. Often adopted.

In this film heating type fixing device, a low heat capacity linear heating element can be used as the heating element provided in the heater, and a thin film with a low heat capacity can be used as the film, so that power saving and weight time shortening (quick start) can be used. Gender) is possible.

In the above film heating method, Patent Document 1 proposes to perform more appropriate start-up control of the fixing device in consideration of not only the time required for image development but also the time required for printing operation preparation. .. As a specific example, when receiving image information, the heater is turned on to the first target temperature (= preheat target temperature), and after reaching this first target temperature, the first target temperature is maintained until the end of image development. do. After that, after the image development is completed, the heater is turned on to the second target temperature (= front rotation target temperature> first target temperature), and after reaching this second target temperature, the second target temperature is reached until the printing preparation is completed. Maintain the target temperature. A control is shown in which the heater is turned up to the third target temperature (= print target temperature> second target temperature) after the printing preparation is completed.

Further, when the user who uses the operation unit (copy operation unit, etc.) of the image forming apparatus or the document reading apparatus touches the image forming apparatus, it is determined that the image forming apparatus will be used soon, and the heater temperature of the fixing portion is raised. Many configurations and techniques have been proposed to shorten the time required for printing, such as controlling the surface temperature of the fixing member.

Japanese Unexamined Patent Publication No. 2005-234065

By the way, in each of the background techniques, the fixing portion is preheated before printing is started, and a case where the paper is stored in a paper cassette or the like of an image forming apparatus is taken into consideration. Therefore, when there is no paper in the image forming apparatus, printing cannot be started until the printing paper is replenished even if the fixing portion is warmed in advance. Therefore, there arises a problem that the temperature of the fixing portion is lowered depending on the elapsed time until the paper is replenished, and the time until the start of printing is delayed. Further, the same problem occurs not only at the start of printing but also when the paper runs out during printing.

Therefore, an object of the present invention is to provide a fixing device and an image forming apparatus capable of shortening the time from printing stop when there is no paper to printing recovery after paper replenishment.

The image forming apparatus according to an embodiment of the present invention includes a fixing belt that rotates, a heating member for heating the fixing belt, a pressure member to form the fixing belt and the pressure to the fixing nip, the paper a paper feed unit intends rows feeding stores, a pre-Symbol paper feed Kamizanryou detecting unit for you detect the sheet presence state of portion, when the paper remaining amount detection section detects no-paper state wherein the heating of the heating member is stopped, and a control unit for performing fixing temperature control mode to start heating of the heating member in response to the sheet feeding unit is opened, the control unit, the fixing temperature In the adjustment mode, the heating of the heating member is stopped every time the fixing belt reaches the target temperature from the opening to the closing of the paper feeding unit, and a predetermined time after the paper feeding unit is opened. It is characterized in that the heating of the heating member is restarted every time.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a fixing device and an image forming apparatus capable of shortening the time from printing stop when there is no paper to returning to printing after replenishing the paper.

The figure explaining the image forming apparatus of an Example Sectional drawing explaining the fixing apparatus of an Example Front view explaining the fixing device of an embodiment Schematic diagram of system configuration (block diagram) of the embodiment The figure which shows the flowchart in Example 1. The figure which shows the temperature transition graph (effect) in Example 1. The figure which shows the flowchart in Example 2. The figure which shows the temperature transition graph (effect) in Example 2.

Hereinafter, embodiments according to the present invention will be described. In the following embodiment, a laser beam printer using an electrophotographic process will be described as an example.

[Image forming device]
FIG. 1 is a cross-sectional view of a printer 1 which is an image forming apparatus of this embodiment.

The printer 1 is an image forming apparatus in which the toner image formed on the photosensitive drum 11 in the image forming unit 10 is transferred to the recording material P, and then the image is fixed on the recording material P by the fixing device 40.

As shown in FIG. 1, the printer 1 includes an image forming unit (image forming station) 10 for forming toner images of each color of Y (yellow), M (magenta), C (cyan), and Bk (black). There is. The image forming unit 10 includes four photosensitive drums 11 (11Y, 11M, 11C, 11Bk) corresponding to each color of Y, M, C, and Bk in order from the left side of FIG. A charger 12, an exposure device 13, a developing device 14, a primary transfer blade 17, and a cleaner 15 are arranged around each photosensitive drum 11. Hereinafter, the procedure for forming a toner image of Bk color will be described, but the procedure for forming a toner image of another color is also the same. The photosensitive drum 11 as an electrophotographic photosensitive member is rotationally driven in the direction of an arrow by a drive source (not shown). A charger 12, an exposure device 13, a developing device 14, a primary transfer blade 17, and a cleaner 15 are arranged around the photosensitive drum 11 in order along the rotation direction thereof.

Next, the procedure for forming the toner image on the recording material P will be described.

After the surface of the photosensitive drum 11 is uniformly charged by the charger 12, the surface of the photosensitive drum 11 is exposed by the exposure apparatus 13 according to the image information to form an electrostatic latent image. Then, the toner is developed in the portion exposed to the laser beam by the developing device 14, and the toner image is formed on the photosensitive drum 11. At this time, the same process is performed for other colors.

The toner image on each photosensitive drum 11 is primarily transferred to the intermediate transfer belt 31 by the primary transfer blade 17, and the toner remaining on the photosensitive drum 11 is removed by the cleaner 15. In this way, the photosensitive drum 11 is in a state where the next image can be formed.

On the other hand, the recording materials P placed on the feeding cassette 20 or the multi-feed tray 25 are sent out one by one by the feeding mechanism (not shown) and sent to the resist roller pair 23. The resist roller pair 23 temporarily stops the recording material P, and if the recording material P is skewed with respect to the transport direction, straightens the direction and synchronizes with the toner image on the intermediate transfer belt 31. The recording material P is fed between the intermediate transfer belt 31 and the secondary transfer roller 35. The secondary transfer roller 35 transfers the toner image on the intermediate transfer belt 31 to the recording material P.

The recording material P to which the toner image is transferred is conveyed to the fixing device 40, and the toner image is fixed on the recording material P by heating and pressurizing.

Next, FIG. 4 shows a schematic configuration diagram of the printer 1 which is the image forming apparatus of this embodiment. The CPU 100 gives a control instruction to the fixing unit 101. Whether or not to give the instruction is configured by the paper feeding unit 102, the paper remaining amount control unit 103, and the image forming unit 104.

[Fixing device]
Next, the fixing device 40 will be described.

FIG. 2 is a cross-sectional view of the fixing device 40, and FIG. 3 is a view illustrating a front view of the fixing device 40.

The film unit 60 that heats the image on the recording material P has a configuration in which the flexible thin-walled fixing film 603 is heated by the heater 600 that contacts the inner surface.

As shown in FIG. 2, in the fixing film 603, a nip portion N is formed by pressurizing the heater 600 and the pressurizing roller 70, and the recording material P supplied to the nip portion N is sandwiched and conveyed. At this time, the heat generated by the heater 600 is applied to the recording material P via the fixing film 603, and the toner image T on the recording material P is fixed to the recording material P.

The film unit 60 is a unit for heating and pressurizing the image on the recording material P, is provided so as to be parallel to the pressurizing roller, and includes a heater 600, a heater holder 601, a support stay 602, and a fixing film 603.

The heater 600 presses the fixing film 603 in the pressure roller 70 direction so that the nip portion N has a desired width. Further, the heater 600 includes a substrate 610 and resistance heating elements 701 and 702 on the substrate 610, and is fixed to a recess on the lower surface of the heater holder 601. In this embodiment, the heating elements 701 and 702 are provided on the back surface side (the side that does not come into contact with the fixing film 603) of the substrate 610, but the heating elements 701 and 702 are not limited to this, and the heating elements 701 and 702 are provided on the front surface side (the fixing film 603 and the same). It may be provided on the contacting side).

A polyimide layer having a thickness of about 10 μm is provided on the surface side of the substrate 610 as a sliding layer, and by reducing the rubbing resistance between the fixing film 603 and the heater 600, wear of the inner surface of the fixing film 603 is suppressed. You can do it. Further, a lubricant such as grease may be applied to the inner surface of the fixing film 603 in order to reduce the rubbing resistance.

The fixing film 603 is a cylindrical film for heating and pressurizing the toner image on the recording material at the nip portion N. In this embodiment, an elastic layer 603b and a release layer 603c are provided on the base material 603a.

Specifically, as the base material 603a, a cylindrical member made of a nickel alloy having an outer diameter of 30 mm, a length of 340 mm, and a thickness of 30 μm is used. Further, a silicone rubber layer having a thickness of 400 μm is formed on the base material 603a as an elastic layer 603b, and a fluororesin tube having a thickness of about 20 μm is coated on the elastic layer 603b as a release layer 603c.

The heater holder 601 (hereinafter referred to as a holder 601) is a member that holds the heater 600 in a pressed state toward the fixing film 603. Further, the heater holder 601 has a semicircular arc shape in cross section, and has a function of regulating the rotation trajectory of the fixing film 603. A highly heat-resistant resin or the like is used for the heater holder 601. In this embodiment, Zenite 7755 (trade name) manufactured by DuPont is used.

The support stay 602 is a member that supports the heater 600 via the heater holder 601. It is desirable that the support stay 602 is made of a material that does not easily bend even when a large load is applied, and SUS304 (stainless steel) is used in this embodiment.

As shown in FIG. 3, the support stay 602 is supported by the flanges 411a and 411b at both ends in the longitudinal direction thereof. The flanges 411a and 411b are collectively referred to as the flange 411. The flange 411 regulates the movement of the fixing film 603 in the longitudinal direction and the shape in the circumferential direction. A heat-resistant resin or the like is used for the flange 411, and PPS (polyphenylene sulfide) is used in this embodiment. A pressure spring 415 is provided between the flange 411 and the pressure arm 414 in a contracted state. With the above configuration, the elastic force of the pressure spring 415 is transmitted to the heater 600 via the flange 411 and the support stay 602. Then, the fixing film 603 is pressed against the pressure roller 70 with a predetermined pressing force to form a nip portion N having a predetermined width. The pressing force in this embodiment is about 156.8N (16kgf) on one end side, and the total pressing force is about 313.6N (32kgf).

Further, the connector 500 is a power feeding member that is electrically connected to the heater 600 in order to apply a voltage to the heater 600, and is detachably attached to one end side in the longitudinal direction of the heater 600.

As shown in FIG. 2, the pressure roller 70 is a member that forms a nip portion N by being pressed by the fixing film unit 60. The pressure roller 70 has a multi-layer structure in which an elastic layer 72 is provided on a metal core 71, and a release layer 73 is further provided on the elastic layer 72.

As the core metal 71, stainless steel, SUM (sulfur and sulfur composite free-cutting steel), and aluminum can be used. As the elastic layer 72, a silicone rubber, a sponge rubber layer, or an elastic bubble rubber can be used. A fluororesin material can be used as the release layer 73.
The pressure roller 70 of this embodiment is composed of a core metal 71 made of stainless steel, an elastic layer 72 of foamed silicone rubber, and a release layer 73 of a fluororesin tube, and has an outer diameter of about 25 mm and a longitudinal length of the elastic layer. It is 330 mm.

As shown in FIG. 3, the core metal 71 of the pressure roller 70 is rotatably held via the side plate 41 and the bearings 42a and 42b, and a gear G is provided at one end of the core metal 71 to provide a motor. The driving force of M is transmitted to the core metal 71. As shown in FIG. 2, the pressure roller 70 driven by the motor M is rotationally driven in the direction of the arrow, and the driving force is transmitted to the fixing film 603 by the nip portion N to rotate the pressurizing roller 70 in a driven manner. In this embodiment, the motor M is controlled by the control circuit 100 so that the surface speed of the pressure roller 70 is 200 mm / sec.

The thermistor (TH) 630, which is the temperature detecting means shown in FIG. 2, is a temperature sensor provided on the back surface side of the heater 600 and detects the temperature of the heater 600. The thermistor 630 is connected to a control circuit (not shown) via an A / D converter (not shown), and transmits an output corresponding to the detected temperature to the control circuit.

The control circuit is a circuit including a CPU that performs operations associated with various controls and a non-volatile medium such as a ROM. A program is stored in this ROM, and the CPU reads and executes the program to execute various controls. The control circuit is electrically connected to the power supply to control the energization of the power supply. Further, the control circuit reflects the temperature information acquired from the thermistor 630 in the energization control of the power supply, and controls the electric power supplied to the heater 600. In this embodiment, a method of adjusting the calorific value of the heater 600 by performing wave number control or phase control with respect to the power output is used, and when the toner on the recording material is fixed, the heater 600 reaches a predetermined temperature. Be maintained.

The heater 600 is formed by coating an aluminum nitride substrate (insulating substrate) with an Ag / Pd resistance material having a thickness of about 10 μm and forming a pattern of heating elements 701 and 702. (Detailed description of each heating element will be described later.) Further, glass (not shown) is coated on the heating elements 701 and 702 to maintain insulation from an electric member such as a thermistor and the surface of a fixing film. Next, each heating element will be described. As the heating elements 701 and 702, a heating element having a longitudinal width of 322 mm is used as the heating element. The heater is energized through the electrodes and generates heat on the substrate 610.

In carrying out this example, the environmental temperature was 23 ° C.

The present invention was carried out with the above as the basic configuration.

As a specific example of the first embodiment, it relates to the control when there is no paper at the start of printing, and the description will be advanced using the flowchart of FIG.

First, with the printer 1 activated, Job (image information) for printing is received from the image forming unit 104 (S11). When the Job is received, the fixing device 40 starts temperature control of the heater 600 for preheating (S12). The fixing film 603 detects a predetermined temperature, and printing is started (S13). At that time, the cassette sensor (not shown) detects whether the paper cassette 20 is in the main body by the paper feed unit 102, and the reflective sensor (not shown) of the paper remaining amount control unit 103 detects the paper cassette 20. Check for the presence of paper inside (S14). If there is paper, printing is started as it is (S20), and the flowchart ends. On the contrary, if there is no paper, printing is interrupted (S15). At that time, the heater 600 in the fixing device 40 is turned off. After that, the user opens the paper feed cassette 20 for paper supply (S16). The cassette sensor detects that the paper cassette 20 has been opened, and the fixing temperature control for preheating is started (S17). After that, the user finishes the paper supply and closes the cassette (S18). After the paper cassette 20 detects the paper cassette 20 again by the cassette sensor, the fixing temperature control for preheating is started (S19). After the temperature of the fixing film 603 rises to a predetermined temperature, printing is started (S20), and the flowchart ends.

Along the above flow, the temperature transition of the fixing film 603 in this embodiment and the conventional example and the time required to restore the printing operation were confirmed (FIG. 6).

In the section a in FIG. 6, up to S16 in the flowchart of FIG. 5 is shown, and since the conventional example and the present embodiment have the same control, the same temperature transition of the fixing film 603 is maintained (this time, the temperature is supplied from no paper). The time until the paper cassette 20 was opened was set to 30.7 seconds).

Next, in section b, the process from the user opening the paper feed cassette 20 for paper supply to the end of paper supply and closing the paper feed cassette 20 (S18) is shown. The target temperature of the fixing film 603 is set at 174 ° C. As a result, in this embodiment, since the fixing film 603 is heated to 174 ° C. again and then the temperature is lowered, the temperature is maintained higher than that of the conventional example (this time, after opening the paper feed cassette 20, the paper is maintained. The time until the paper cassette 20 was closed after replenishment was set to 30 seconds).

Finally, regarding the c section, the section from the user closing the paper cassette 20 to the start of printing (S20) is shown. In this example, since the temperature of the fixing film 603 remained higher than that in the conventional example, it was possible to obtain a result that the recovery time until printing was shorter by 2.5 seconds than in the conventional example.

In this embodiment, the time from no paper to opening the paper cassette 20, the time to replenish the paper after opening the paper cassette 20 and closing the paper cassette 20, and the target temperature of the fixing film 603 are set. As mentioned above, the numerical value used is an example and is not limited to this numerical value.

As a specific example of the second embodiment, it relates to the control when there is no paper during printing, and the description will be advanced using the flowchart of FIG. 7.

First, while the printer 1 is printing (S21), the presence or absence of paper in the paper feed cassette 20 is confirmed by a sensor (not shown) of the paper feed unit of the paper remaining amount control unit 103 (S22). If there is paper, printing is continued as it is (S29), and the flowchart ends. On the contrary, if there is no paper, printing is interrupted (S23). At that time, the heater 600 in the fixing device 40 is turned off. After that, the user opens the paper feed cassette 20 for paper supply (S24). The cassette sensor detects that the paper cassette 20 has been opened, and the fixing temperature control for preheating is started (S25). After that, the user finishes the paper supply and closes the paper feed cassette 20 (S26). After the paper cassette 20 detects the paper cassette 20 again by the cassette sensor, the fixing temperature control for preheating is started (S27). After the temperature of the fixing film 603 rises to a predetermined temperature, printing is restarted (S28), and if printing can be completed without running out of paper until the end, the flowchart ends.

In line with the above flow, the temperature transitions in this example and the conventional example and the time required for recovery were confirmed (Fig. 8).

In the section a of FIG. 8, up to the flowchart (S24) of FIG. 7 is shown, and since the conventional example and the present embodiment perform the same control, the same temperature transition is maintained (note that this time, the paper is fed from no paper). The time until the cassette 20 was opened was set to 30.7 seconds).

Next, in section b, the process from the user opening the paper feed cassette 20 for paper supply to the end of paper supply and closing the paper feed cassette 20 (S26) is shown. The target temperature of the fixing film 603 is set at 174 ° C. As a result, in the embodiment, since the fixing film 603 is heated to 174 ° C. again and then the temperature is lowered, the temperature is maintained higher than that in the conventional example (this time, the paper is replenished after opening the paper feed cassette 603). The time until the paper cassette 20 was closed later was set to 30 seconds).

Finally, regarding the c section, the section from the user closing the paper cassette 20 to the restart of printing (S28) is shown. In this example, since the temperature of the fixing film 603 was higher than that in the conventional example, it was possible to obtain a result that the recovery time until printing was 2.2 seconds shorter than that in the conventional example.

In this embodiment, the time from no paper to opening the paper cassette 20, the time to replenish the paper after opening the paper cassette 20 and closing the paper cassette 20, and the target temperature of the fixing film 603 are set in advance. However, the numerical value is an example and is not limited to this numerical value.

(Other examples)
Although the examples to which the present invention can be applied have been described above, the numerical values such as dimensions and conditions exemplified in each embodiment are merely examples and are not limited to these numerical values. Numerical values can be appropriately selected as long as the invention can be applied. Further, the configuration described in the examples may be appropriately changed to the extent to which the invention can be applied (for example, a roller fixing method or the like may be used, or a standby temperature control type fixing device may be used for control as in the present embodiment. May be done).

Further, in this embodiment, since the setting is made in 30 seconds from opening the paper feed cassette 20 without paper to closing the paper feed cassette 20 with paper replenishment, the heater 600 temperature control frequency of the fixing device 40 can be adjusted only once. However, the temperature of the fixing may be adjusted a plurality of times according to the time after the paper cassette 20 is opened (the time that the paper cassette 20 is open is long (= the time during which it is interrupted). Long), effective when the temperature of the fixing film 603 drops considerably).

The fixing film 603 is not limited to a configuration in which the inner surface thereof is supported by the heater 600 and driven by the rollers 70. For example, it may be a unit system that is spread over a plurality of rollers and driven by any one of the plurality of rollers. However, from the viewpoint of reducing the heat capacity, the configuration as in Examples 1 and 2 is desirable.

What forms the fixing film 603 and the nip portion N is not limited to the roller member such as the roller 70. For example, a pressure belt unit in which a belt is spanned over a plurality of rollers may be used.

The image forming apparatus described using the printer 1 as an example is not limited to the image forming apparatus for forming a full-color image, and may be an image forming apparatus for forming a monochrome image. Further, the image forming apparatus can be implemented in various applications such as a copying machine, a fax machine, and a multifunction device having a plurality of these functions, in addition to necessary equipment, equipment, and a housing structure.

The image forming apparatus in the above description is not limited to the apparatus for fixing the unfixed toner image on the sheet P. For example, a device for fixing the semi-fixed toner image to the sheet P or a device for applying heat treatment to the fixed image may be used. Therefore, the fixing device 40 as the image forming device may be, for example, a surface heating device that adjusts the gloss and surface properties of the image.

As described above, according to the present invention, it is possible to provide a fixing device and an image forming device that can shorten the time from printing stop when there is no paper to printing recovery after paper replenishment.

1 image forming device (printer), 20 paper cassette, 40 fixing device,
60 film unit, 70 pressure roller, 500 connector,
600 heater (fixing heater), 601 heater holder, 602 support stay,
603 fixing film, 610 heater substrate, 630 temperature detecting means (thermistor),
701,702 Resistor heating element, P recording paper (recording material),
T toner image, N nip

Claims (3)

With a rotating fixing belt,
A heating member for heating the fixing belt and
A pressure member that press-contacts with the fixing belt to form a fixing nip, and
A paper feed unit intends rows feeding stores the paper,
And for Kamizanryou detection unit detect the sheet presence state before Symbol paper feed portion,
When the paper remaining amount detecting unit detects that there is no paper, the heating of the heating member is stopped, and when the paper feeding unit is opened , the heating of the heating member is started to set the fixing temperature control mode. Equipped with a control unit to perform
In the fixing temperature control mode, the control unit stops heating of the heating member each time the fixing belt reaches a target temperature from opening to closing of the paper feeding unit, and feeds the paper. Every time a predetermined time elapses after the portion is opened, the heating of the heating member is restarted.
An image forming apparatus characterized in that. The fixing temperature control mode is performed at the start of printing or during printing.
The image forming apparatus according to claim 1. The fixing belt is a thin-walled cylindrical film member.
The heating member is a planar heater that rubs against the inner peripheral surface of the film member.
The image forming apparatus according to claim 1 or 2.

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