JP2001290389A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming device capable of excellently forming an image without being affected by ambient temperature by appropriately setting target temperature or supply power based on room temperature information. SOLUTION: This image forming device is provided with a heating temperature detecting means 515 detecting the temperature of an image heating device in order to control the temperature of an image heating device R, a room temperature detecting means 106 detecting the room temperature, a temperature control means 13a controlling the device R to be at fixed target temperature and a target temperature setting means 13b setting the target temperature. Then, the target temperature is set to an optional value by the setting means 13b based on the room temperature information by the detecting means 106.

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 an image heating device.

[0002]

2. Description of the Related Art Conventionally, in an image heat fixing device (image heating device) provided in an image forming apparatus employing an electrophotographic system, an electrostatic recording system, etc., a sheet material carrying a toner image is pressed against each other. The toner image is fixed as a permanent image on a sheet material by passing through a pressure contact nip area formed by a fixing roller and a pressure roller that rotate.
A so-called heat roller type heat fixing unit is widely used.

Further, a heating and fixing means which does not supply electric power at the time of standby and keeps power consumption as low as possible, more specifically, a thin-walled member between a heating element (hereinafter referred to as a heater) attached to a support and a pressure roller. With a film (hereinafter, referred to as a fixing film) interposed, a sheet material on which an unfixed toner image is formed is passed between a heater and a pressure roller in a state of being in close contact with the film, and a toner image is formed on the sheet material. There is a heating and fixing means by a film heating method for heating and fixing the toner.

The above two types of heat fixing means constituting the image heat fixing device have one or more fixing temperature detecting means in order to control the temperature for heat fixing. The fixing temperature detecting means generally uses a thermistor in many cases, and is provided in contact with the heater or the pressure roller to detect the temperature of the heater or the pressure roller. Recently, a method of measuring the radiant heat of the heater or the pressure roller to detect the temperature at which the heating and fixing is performed has been studied.

FIG. 7 is a schematic configuration diagram (cross-sectional view) showing a typical example of a heating and fixing means using the above-mentioned film heating method. In FIG. 7, the image heat fixing device 5
Reference numeral 10 denotes a heater 511 and a guide member 51 as a support.
2, a fixing film 513, and a pressure roller 514 that presses against the fixing film 513 to form a nip portion (heating nip portion) N, and the like. The recording material P is passed through and the heater 51
1, the toner image T is fixed on the sheet material P.

[0006] The heater 511 is fixed to a guide member 512 for guiding the rotational movement of the fixing film 513. The guide member 512 is formed of, for example, a heat-resistant resin member, holds the heater 511 as a heating member, and also serves as a guide for the fixing film 513. Further, heat-resistant grease or the like is interposed between the fixing film 513 and the outer peripheral surfaces of the heater 511 and the guide member 512 in order to enhance the rotational slidability with the fixing film 513. In order to detect the temperature of the heater 511, a thermistor 515 is generally provided as a fixing temperature detecting unit. As a typical means for installing the thermistor 515, there is a method of bonding the heater 511 to the heater 511 with a heat-resistant adhesive or a method of pressing the heater 511 by using the pressure of a spring member.

[0007] Based on the temperature detected by the thermistor 515, the temperature control means adjusts the power supply to the heater 511, and performs feedback control so that the temperature detected by the thermistor 515 becomes a predetermined target temperature. Thus, the fixing nip N is maintained at a desired fixing temperature.

[0008]

However, if the target temperature for temperature control is uniquely determined under normal conditions,
When the temperature (room temperature) of the environment in which the image forming apparatus is installed is low (low temperature environment), the amount of heat taken by surrounding members and the recording material increases, and thick paper or the like having a large heat capacity is passed. In addition, poor fixing is likely to occur. Further, when the ambient temperature (room temperature) is high (under a high temperature environment), the amount of heat taken by the surrounding members and the recording material decreases, and a high-temperature offset or overshoot occurs when the temperature of the non-sheet passing portion rises. In such a case, a smear (a problem in which an image is distorted by slipping between the film and the paper) is likely to occur.

Accordingly, an object of the present invention is to provide an image forming apparatus capable of forming a good image without being affected by an environmental temperature by appropriately setting a target temperature and a supply power based on room temperature information. I have.

[0010]

An image forming apparatus according to the present invention is characterized by the following constitution in order to solve the above-mentioned problems.

[1]: A heating temperature detecting means for detecting the temperature of the image heating apparatus for controlling the temperature of the image heating apparatus, a room temperature detecting means for detecting the room temperature, and setting the image heating apparatus to a predetermined target temperature. Temperature control means for controlling, and target temperature setting means for setting the target temperature, wherein the target temperature setting means sets the target temperature to an arbitrary value based on room temperature information from the room temperature detecting means. Characteristic image forming apparatus.

[2] In the image forming apparatus described in [1], the target temperature control means controls the image heating apparatus to a plurality of target temperatures, and at least one of the target temperatures is set to the target temperature. An image forming apparatus, wherein a setting unit sets an arbitrary value based on the room temperature information.

[3] In the image forming apparatus described in [2], the image heating device is controlled to a first target temperature during a start-up period, and is controlled to a second target temperature during an image heating period. An image forming apparatus, comprising:

[4] The image forming apparatus according to [3], wherein the target temperature setting means sets the first target temperature to an arbitrary value based on the room temperature information. apparatus.

[5] The image forming apparatus according to [3] or [4], wherein the target temperature setting means sets the second target temperature to an arbitrary value based on the room temperature information. Image forming apparatus.

[6]: In the image forming apparatus according to any one of [1] to [5], paper feed timing control for controlling the time from when the power supply to the image heating device is started to when the recording material is fed. An image forming apparatus, wherein the sheet feeding timing is set to an arbitrary value by the sheet feeding timing control unit based on room temperature information obtained by the room temperature detecting unit.

[7] In the image forming apparatus according to any one of [1] to [6], the target temperature setting means sets the duration of the first target temperature to an arbitrary value based on the room temperature information. An image forming apparatus.

[8]: In order to control the temperature of the image heating apparatus, a fixing temperature detecting means for detecting the temperature of the image heating apparatus, a room temperature detecting means for detecting the room temperature, and a constant until the image heating apparatus reaches a target temperature. Power control means for applying power of the power control means, and power setting means for setting the power of the power control means to an arbitrary value, and the power setting means sets the power of the power control means to an arbitrary value based on the room temperature information. The image forming apparatus is set to:

[0019]

[9]: In the image forming apparatus according to [8], the image heating device is controlled to a target temperature in a plurality of stages, and the power setting unit controls the power control so that the target temperature reaches at least one of the target temperatures. An image forming apparatus, wherein the power of the means is set based on the room temperature information.

[10]:

In the image forming apparatus according to [9], the image heating device is controlled to a first target temperature during a start-up period, and is controlled to a second target temperature during an image heating period. The image forming apparatus, wherein the power setting unit sets the power of the power control unit based on the room temperature information until the temperature reaches a second target temperature from the temperature.

[11]: The image heating device has a film and a pressing member which presses the film to form a heating nip, and heats a recording material on which an image is formed by passing the recording material through the heating nip. The image forming apparatus according to any one of [1] to [10], wherein the image forming apparatus is a film heating type apparatus.

[12]: An unfixed image is formed on the recording material by the image forming means, and the image is heated by the image heating device and thermally fixed on the recording material. 10] The image forming apparatus according to any one of the above.

[0023]

FIG. 1 is a view for explaining an image forming apparatus (printer) according to a first embodiment of the present invention.

The sheet material (recording material) P loaded in the sheet cassette 1 is fed by a cassette sheet feeding roller 3 and is conveyed by a conveying roller 4 to a sheet conveying path 5 in the printer.
The sheet is conveyed above, is fed to the image forming means side at a predetermined timing by the registration roller 6, and the position of the front end and the rear end is detected by the paper feed sensor 7.

On the other hand, the image formation is started in synchronization with the detection of the leading edge of the sheet material by the paper feed sensor 7,
The upper portion is scanned and exposed by the optical scanning device 15 to form a latent image,
The latent image is developed by the developing means 16 to form a toner image T.

The sheet material P and the toner image T are introduced into an opposing portion (transfer portion) m between the photosensitive drum 9 and the transfer roller 8, and the toner image T is transferred to the sheet by the transfer bias applied to the transfer roller 8. The image is transferred onto the material P.

The toner image T is formed by these image forming means.
Is heated and pressed by an image heat fixing device (image heating device) 510, the toner image T is fixed on the sheet material, and then discharged by the discharge roller 12.

Since the schematic configuration of the image heat fixing device 510 is the same as that of the above-described device of FIG. 7, the same components are denoted by the same reference numerals and the description thereof will not be repeated.

The temperature of the image heat fixing device 510 is adjusted by detecting the temperature of the ceramic heater 511 by a thermistor (heating temperature detecting means) 515, and by controlling the target temperature control means 13a included in the CPU 13 based on the detected temperature. The driving circuit 14 is controlled, and the power applied to the ceramic heater 511 is adjusted so that the detected temperature becomes the target temperature set by the target temperature setting means.

In the present embodiment, the ambient temperature (room temperature) is detected by a room temperature detecting means (room temperature thermistor) 106 provided near the air supply port in the image forming apparatus, and the target temperature can be arbitrarily determined based on the room temperature information. Is set to the value.

Hereinafter, this operation will be described with reference to the flowchart of FIG.

When the power switch of the present apparatus is turned on (30)
1) The temperature information Tm of the fixing temperature thermistor 515 and the room temperature information Tr of the room temperature thermistor 106 are stored in the CPU 13 respectively.
Is always transmitted as an electric signal to the target temperature control means 13a. Subsequently, the apparatus 101 enters a standby state (302) waiting for a print start command, and when the CPU 13 receives the print start command (303), room temperature information determination for determining a magnitude relationship between the room temperature information Tr and a predetermined temperature Tx. Control is performed (304).

At this time, if the environmental temperature is high and Tr ≧ Tx (305), the target temperature is set to Tt1 by the target temperature setting means 13b (306).

Conversely, if the environmental temperature is low and Tr <Tx (307), the target temperature is set to Tt2 by the target temperature setting means 13b (308).

If this control target temperature is set to a value such that Tt1 <Tt2, the fixing heater control target temperature is lowered when the environmental temperature is high (that is, even when the amount of heat applied to the fixing unit is relatively small can be sufficiently fixed). so,
It is possible to prevent a problem such as hot offset that occurs when the amount of heat applied to the image heat fixing device 510 and the sheet material P is too large.

Conversely, when the environmental temperature is low (that is, the image cannot be fixed unless the amount of heat applied to the image heat fixing device 510 and the sheet material P is increased), the fixing heater control target temperature is increased to increase the image heat fixing device 510. In addition, it is possible to prevent problems such as poor fixing that occur when the amount of heat applied to the sheet material P is too small.

The threshold value Tx in the room temperature information determination control
Was set to Tx = 5 ° C. to 35 ° C. The value is the value of heater 5
It is possible to arbitrarily set a fixed value that is most appropriate in accordance with the device configuration, such as the output of the device 11 and the location of the room temperature thermistor 106.

<Second Embodiment> This embodiment is characterized in that the target temperature is controlled in a plurality of stages, and the other structure is the same as that of the first embodiment.

FIG. 3 is a diagram showing the fixing temperature Tm at each timing during the image forming operation of the present apparatus.

As shown in the figure, in the present apparatus, the first target temperature T1 and the first sheet from t1 are used from the start t0 to the timing t1 immediately before the sheet material P reaches the fixing nip portion N. The temperature is controlled at the normal target temperature (second target temperature) T2 until the sheet P exits the fixing nip N by t2, and the sheet interval is between t2 and t3 when the sheet P does not exist in the fixing nip N. Target temperature T
Temperature is controlled by k.

By setting the relationship between the target temperature T1 at the start of startup (pre-rotation) and the normal target temperature T2 as T2 ≧ T1, even when the normal target temperature T2 is set to a high temperature, the image heat It is possible to prevent a problem that the fixing device 510 becomes unnecessarily warmed and causes hot offset.

In this embodiment, the room temperature thermistor 1
The first target temperature T1 is changed based on the 06 detection information Tr.

That is, in the room temperature information determination control (304) of FIG. 2, if the ambient temperature is low and Tr <Tx (30)
7) The first target temperature T is set by the target temperature setting means 13b.
By setting 1 to Tt2 (308), a fixing failure in a low temperature environment is prevented. If the ambient temperature is high and Tr ≧ Tx (305), the first temperature is set by the target temperature setting means 13b.
By setting the target temperature T1 to Tt1 (306), hot offset due to the image heat fixing device 510 being too warm is prevented.

Further, the first target temperature T1 is fixed, and the second target temperature T1 is fixed.
The target temperature may be set to an arbitrary value according to the room temperature information Tr. Further, not only the first target temperature T1 but also the second target temperature may be set to an arbitrary value at the same time according to the room temperature information Tr.

Further, the target temperature setting means 13b may set the duration of the first target temperature T1 to an arbitrary value based on the room temperature information Tr. For example, if Tr ≧ Tx in the room temperature information determination control (304) (305) the first
The duration of the target temperature T1 is shortened to reduce the amount of heat applied to the fixing device 510 to prevent an excessive temperature rise (306).
Conversely, if Tr <Tx in the room temperature information determination control (304) (307), the duration of the first target temperature T1 is lengthened to increase the amount of heat applied to the fixing device 510 to prevent insufficient fixing (308).

<Third Embodiment> This embodiment is characterized in that the power supplied to the heater is set to an arbitrary value based on the room temperature information. Specifically, as shown in FIG. 4, compared to the first embodiment, a power setting means 13c is provided in place of the target temperature setting means 13b, and the power setting means 13c supplies power to the heater 11 based on room temperature information. The power value is set, and the heater drive circuit (power control means) 14 supplies the set power to the heater.

FIG. 5 is a flowchart at the time of the printing operation of the present embodiment.

In this embodiment, the room temperature information determination control (30
If Tr ≧ Tx in 4), (305) the fixing heater 511
Is set to Wl (306). Conversely, if Tr <Tx in the room temperature information determination control (304) (30
7) The power supply to the fixing heater 511 is set to W2 (308).

At this time, if the supply power is set to a value of Wl <W2, the fixing heater is used when the ambient temperature is high (that is, when the power applied to the image heat fixing device 510, that is, when the amount of heat can be sufficiently fixed, can be sufficiently fixed). Overshoot that occurs when the amount of heat applied to the image heat fixing device 510 and the sheet material (printing paper) P is excessively applied by lowering the supplied power (the temperature rises above the target temperature when the temperature rises). By raising the temperature gently, it is possible to prevent problems such as hot offset due to overfixing that occurs when too much heat is applied.

Conversely, when the ambient temperature is low (that is, fixing cannot be performed unless the amount of heat applied to the image heat fixing device 510 is increased), the predetermined temperature can be quickly raised by increasing the power applied to the fixing heater. ,
Paper is fed after a certain period of time after the start of energization of the fixing heater 511, and the image heat fixing device 5 is moved within a time uniquely determined by the distance to the image heat fixing device 510 and the sheet conveyance speed.
Since the amount of heat applied to the sheet 10 can be increased, it is possible to prevent problems such as defective fixing that occur when the amount of heat applied to the image heat fixing device 510 and the sheet material P is too small.

The control based on the room temperature information may be performed in combination with the above-described embodiment. For example, in steps 306 and 308, the target temperature and the supplied power may be arbitrarily set.

<Fourth Embodiment> This embodiment is characterized in that the sheet material feeding timing is arbitrarily set based on room temperature information. Compared with the first embodiment, the sheet material P is supplied after the sheet supply timing control means included in the CPU 13 starts energizing the image heat fixing device 510 based on the room temperature information instead of the target temperature setting means 13b.
The difference is that the time until the sheet is fed is arbitrarily set, and the other configurations are the same.

In the present embodiment, in the room temperature information determination control (304) of FIG. 2, if the ambient temperature is low and Tr <Tx (307), the time until paper feeding is set longer.
By increasing the amount of heat applied to the fixing device 510 (308), poor fixing in a low-temperature environment is prevented. If the ambient temperature is high and Tr ≧ Tx (305), the time until paper feeding is set short, and the amount of heat given to the fixing device 510 is reduced (306). Prevent hot offset.

The control based on the room temperature information may be performed in combination with the above-described embodiment. For example, not only the time until sheet feeding in steps 306 and 308 but also the target temperature and / or the supplied power can be arbitrarily set. May be set.

<Others> In the first embodiment shown in FIG. 1, a fixing temperature thermistor 515
However, as shown in FIG. 6, a configuration may be adopted in which two fixing temperature thermistors 402 are provided and one of them is used as the first temperature detecting means. The other configuration is the same.

For example, when the heater 511 has a plurality of heat generating portions in accordance with the size of the recording material that can be passed, and a plurality of fixing temperature thermistors 402 corresponding to the heating portions are arranged, the recording material passed during printing is used. The fixing temperature thermistor 402 on the side selected according to the size may be used as the heating temperature detecting means.

In the above embodiment, a tensionless film heating system is described, but a system in which a film stretched between a plurality of members such as a heater and a driving roller may be driven to rotate.

The heat source of the image heat fixing device is not limited to the ceramic heater, but an electromagnetic induction is generated by applying a magnetic flux to a conductive layer provided on the film to generate an induced current and generating heat by the Joule heat. It may be of the type.

Further, the present invention is not limited to the film driving system, but can be similarly applied to an image forming apparatus having a heat roller type image heating apparatus.

The image heating device of the present invention is not limited to a fixing device, but may be a device for modifying the surface condition (such as gloss) of an image, or a device for temporary attachment.

[0061]

As described above, according to the present invention,
By appropriately setting the target temperature and the supplied power based on the room temperature information, it is possible to provide an image forming apparatus capable of forming a good image without being affected by the environmental temperature.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an image forming apparatus according to a first embodiment of the present invention.

FIG. 2 is a flowchart at the time of a printing operation according to the first embodiment;

FIG. 3 is an explanatory diagram of first and second target temperatures in a second embodiment.

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

FIG. 5 is a flowchart at the time of a printing operation in a third embodiment.

FIG. 6 is an explanatory view of another embodiment.

FIG. 7 is a schematic configuration diagram of a conventional image heating apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 paper feed cassette 3 cassette feed roller 4 transport roller 5 sheet material transport path 6 registration roller 7 paper feed sensor 8 transfer roller 9 photosensitive drum 11 heater 12 paper discharge roller 13 CPU 13a target temperature control means 13b target temperature setting means 13c Setting unit 14 Heater driving circuit 15 Optical scanning device 16 Developing unit 101 Main unit 106 Room temperature thermistor 402 Fixing temperature thermistor 510 Image heat fixing device (Image heating fixing unit) 511 Ceramic heater 512 Guide member 513 Fixing film 514 Pressure roller 515 Thermistor N Fixing nip P Sheet material (recording material) T Toner image

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H027 DA11 DA12 DA38 EA12 EC20 ED17 ED25 EE02 EE07 EF06 EF09 JA11 JC08 2H033 AA02 BA11 BA12 BA25 BA30 BE03 CA03 CA04 CA05 CA07 CA28 CA30 CA32 CA48 9A001 HH34 JJ35

Claims (12)

[Claims] 1. A heating temperature detecting means for detecting a temperature of the image heating apparatus, a room temperature detecting means for detecting a room temperature, and controlling the image heating apparatus to a constant target temperature in order to control a temperature of the image heating apparatus. Temperature control means, and target temperature setting means for setting the target temperature, wherein the target temperature setting means sets the target temperature to an arbitrary value based on room temperature information from the room temperature detecting means. Image forming apparatus. 2. The image forming apparatus according to claim 1, wherein said target temperature control means controls said image heating apparatus to a plurality of target temperatures, and at least one of said target temperatures is set to said target temperature setting means. Is set to an arbitrary value based on the room temperature information. 3. The image forming apparatus according to claim 2, wherein the image heating device is controlled to a first target temperature during a startup period, and is controlled to a second target temperature during an image heating period. An image forming apparatus comprising: 4. The image forming apparatus according to claim 3, wherein said target temperature setting means sets a first target temperature to an arbitrary value based on said room temperature information. 5. The image forming apparatus according to claim 3, wherein said target temperature setting means sets a second target temperature to an arbitrary value based on said room temperature information. apparatus. 6. The image forming apparatus according to claim 1, further comprising a paper feed timing control unit for controlling a time from when the power supply to the image heating device is started to when a recording material is fed. An image forming apparatus, wherein the paper feed timing is set to an arbitrary value by the paper feed timing control means based on room temperature information obtained by the room temperature detection means. 7. The image forming apparatus according to claim 1, wherein the target temperature setting unit sets a duration of the first target temperature to an arbitrary value based on the room temperature information. Image forming apparatus. 8. A fixing temperature detecting means for detecting the temperature of the image heating device, a room temperature detecting means for detecting the room temperature, and a constant electric power until the image heating device reaches a target temperature for controlling the temperature of the image heating device. And power setting means for setting the power of the power control means to an arbitrary value, and setting the power of the power control means to an arbitrary value by the power setting means based on the room temperature information. An image forming apparatus. 9. The image forming apparatus according to claim 8, wherein the image heating device is controlled to a target temperature in a plurality of stages,
The image forming apparatus, wherein the power setting means sets the power of the power control means based on the room temperature information so as to reach at least one of the target temperatures. 10. The image forming apparatus according to claim 9, wherein the image heating device is controlled to a first target temperature during a startup period, and is controlled to a second target temperature during an image heating period. The image forming apparatus, wherein the power setting means sets the power of the power control means based on the room temperature information until the first target temperature reaches the second target temperature. 11. A film, wherein the image heating device has a film, and a pressure member that presses against the film to form a heating nip, and heats a recording material on which an image is formed by passing the recording material through the heating nip. The image forming apparatus according to claim 1, wherein the image forming apparatus is a heating type apparatus. 12. An unfixed image is formed on a recording material by an image forming means, and the image is heated by the image heating device and thermally fixed on the recording material.
The image forming apparatus according to claim 1.