JPH08314301A - Image forming device and image forming method for image forming device - Google Patents

Abstract

PURPOSE: To fix the image transferred onto a recording medium with a uniform heat quantity while reducing the electric power to be consumed by varying the fixing and transporting speed at the time of passing the recording medium through a fixing means and varying the fixing temp. of the fixing means in accordance with the fixing and transporting speed. CONSTITUTION: This image forming device is provided with rollers 21, 22 for transporting the recording medium, a motor 5 for driving the fixing device 8, a printer controller 1 for varying the fixing and transporting speed at the time the recording medium passes the fixing device 8 by controlling the motor 5 and a printer controller 1 for varying the fixing temp. of the fixing device 8 via a lighting circuit 3 in accordance with the fixing and transporting speed. This printer controller 1 varies the fixing and transporting speed at the time the recording medium passes the fixing device 8 by controlling the motor 5 and the printer controller 1 varies the fixing temp. of the fixing device 8 in accordance with the fixing and transporting speed. As a result, the image transferred to the recording medium is fixed with the uniform heat quantity while the electric power to be consumed by the fixing device 8 is reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus having a heat fixing means for performing a heat fixing process on a conveyed recording medium and an image forming method of the image forming apparatus.

[0002]

2. Description of the Related Art Conventionally, recording sheets of this type of image forming apparatus are conveyed from image formation in an electrophotographic process to heat fixing.
Until the sheet is discharged, the same driving source is used at a constant speed.

[0003]

However, in order to obtain the required amount of heat for fixing the recording material onto the recording medium, either the heat (electric power) of the heater or the fixing time must be increased.

Therefore, in the conventional image forming apparatus, when the temperature of the fixing device becomes lower than the specified value, the feeding timing is sent until the temperature reaches the specified value, or the printing speed of the entire apparatus is lowered to fix the image. Is being maintained. This is a problem particularly in a printer having a heat fixing device using a halogen heater, in terms of power saving and speedup.

The present invention has been made to solve the above problems, and an object of the first to ninth inventions of the present invention is to change the fixing temperature when changing the fixing conveyance speed. It can be adjusted to secure the time for the recording medium to be present in the fixing device and to obtain heat, and to make the total amount of heat obtained by the recording paper the same, which can be done without slowing down the process before fixing.
When the recording medium passes the fixing device, the conveying speed of the recording medium is increased, the time decelerated by the fixing device is recovered, and the time in the fixing device is increased without increasing the total time for conveying the recording paper.
(EN) An image forming apparatus and an image forming method of the image forming apparatus capable of reducing the printing time without increasing the electric power of the heater, and further reducing the electric power of the heater and increasing the electric power consumption without increasing the printing time. That is.

[0006]

A first aspect of the present invention is an image forming apparatus including a fixing unit that heats and presses a developer transferred onto a recording medium to fix the same. Means, a driving means for driving the fixing means, and a first means for controlling the driving means to vary a fixing conveyance speed when the recording medium passes through the fixing means.
The speed varying means and the temperature varying means for varying the fixing temperature of the fixing means based on the fixing conveying speed are provided.

According to a second aspect of the present invention, the first speed varying means reduces the fixing conveyance speed when the recording medium passes the fixing means when the recording medium passes the fixing means. To do.

According to a third aspect of the present invention, the temperature varying means varies the fixing temperature of the fixing means based on the varied fixing conveying speed.

A fourth aspect of the present invention is a sheet discharging and conveying unit that discharges and conveys the recording medium that has passed through the fixing unit, a sheet discharging driving unit that drives the sheet discharging and conveying unit, and the sheet discharging unit. Second speed varying means for varying the discharge transport speed of the recording medium for discharging and transporting the recording medium by controlling the driving means is provided.

According to a fifth aspect of the present invention, the second speed varying means increases the discharge transport speed from the fixing transport speed.

According to a sixth aspect of the present invention, the temperature varying means varies the lighting cycle for lighting the fixing heater of the fixing means.

According to a seventh aspect of the present invention, a measuring means is provided for measuring the distance between each recording medium that is continuously conveyed, and the first speed varying means is such that the recording medium passes through the fixing means. The fixing conveyance speed at the time of changing is varied based on the separation length measured by the measuring means.

According to an eighth aspect of the present invention, the temperature varying means changes the varied fixing temperature of the fixing means when the varied fixing conveying speed changes below a prescribed speed.

A ninth aspect of the present invention is an image forming method for an image forming apparatus, which comprises a fixing unit for fixing the developer transferred onto the recording medium by applying heat and pressure, and fixing the image when passing through the fixing unit. It comprises a speed changing step of changing the conveying speed and a temperature changing step of changing the fixing temperature of the fixing means based on the fixing conveying speed.

[0015]

In the first aspect of the invention, the first speed varying means controls the driving means to vary the fixing transport speed when the recording medium passes through the fixing means, and based on the fixing transport speed. The temperature varying unit varies the fixing temperature of the fixing unit to reduce the power consumed by the fixing unit and fix the image transferred to the recording medium with a uniform amount of heat even when the fixing conveyance speed changes. It is possible.

In the second invention, the first speed varying means reduces the fixing conveyance speed when the recording medium passes the fixing means, when the recording medium passes the fixing means, It is possible to reduce the power consumed by the fixing unit.

In the third invention, the temperature varying means is
The fixing temperature of the fixing unit is changed based on the changed fixing conveyance speed, and the image transferred to the recording medium can be fixed with a uniform heat amount even if the fixing conveyance speed changes.

In the fourth invention, the second speed changing means controls the paper discharge driving means to change the discharge speed of the recording medium for discharging and discharging the recording medium, and the speed is reduced at the time of fixing. It is possible to minimize the change in the total transport time required for transport by compressing the excess of the transport time as much as possible.

In the fifth aspect of the invention, the second speed varying means increases the discharge conveyance speed to be higher than the fixing conveyance speed to offset the excess of the conveyance time due to the conveyance speed decelerated during fixing. It enables conveyance that ignores deceleration during fixing.

In the sixth invention, the temperature varying means is
By changing the lighting cycle for turning on the fixing heater of the fixing unit, it is possible to reliably control the amount of heat applied to the recording medium by the fixing unit so that excessive heat is not applied to the recording medium.

In the seventh invention, the first speed changing means changes the fixing conveyance speed when the recording medium passes through the fixing means on the basis of the separation length measured by the measuring means to fix the fixing medium. It is possible to convey a recording medium at an optimum conveying speed at which uniform heat is applied to a recording medium that is continuously conveyed while the conveying speed is variable.

In the eighth invention, the temperature varying means is
It is possible to prevent the excessive heat from being applied to the recording medium by changing the fixing temperature of the fixing unit which has been changed, when the changed fixing conveyance speed has changed below the specified speed.

In the ninth aspect of the invention, the fixing conveyance speed when passing through the fixing means is varied, and the fixing temperature of the fixing means is varied based on the fixing conveyance speed to reduce the power consumed by the fixing means. It is possible to automate the process of fixing the image transferred onto the recording medium with a uniform amount of heat while reducing the amount of heat and even when the fixing conveyance speed changes.

[0024]

【Example】

[First Embodiment] FIG. 1 is a schematic block diagram for explaining the structure of a recording medium (for example, recording paper) transport mechanism in an image forming apparatus according to the first embodiment of the present invention. Shows. The mechanism and operation will be described below.

The main body of the laser printer (hereinafter referred to as the main body) has a cassette for accommodating the recording paper S (not shown), and the recording paper S is repeatedly conveyed from the cassette to the image forming section 7 of the well-known electrophotographic process downstream. A paper feed mechanism is provided,
Sensors 11 and 12 that detect the transport state are provided.

A fixing device 8 for thermally fixing the toner image formed on the recording paper S is provided downstream thereof, and the fixing paper 8 is fed into the entrance of the recording paper S. A fixing paper feed sensor 13 for detecting the conveyance state is arranged, a fixing paper ejection sensor 14 for detecting the paper ejection / conveyance state is provided at the exit, and a recording paper sheet for which recording is completed is provided downstream of the fixing device 8. S
There is provided a loading tray (not shown) for loading.

Reference numeral 1 denotes a printer control device for controlling the main body, which is composed of a CPU (microcomputer) equipped with a timer, a ROM, a RAM, etc., various input / output control circuits (not shown), etc. The program is recorded.

The printer control device 1 also controls the drive and drive speed of the motors 4 and 5 via the motor drive circuit 2 (for example, the drive speed of a pulse motor is changed by a pulse signal). The drive of the image forming unit of the electrophotographic process is given by the motor 4, and the drive of the fixing unit is given by the motor 5.

A halogen heater 9 is provided in the fixing device 8, and ON / OFF of the halogen heater 9 is controlled by the printer controller 1 via the lighting circuit 3.

Correspondence between the present embodiment and each means of the first to fourth and seventh inventions and their operation will be described below with reference to FIG.

The first invention is an image forming apparatus having a fixing means (fixing device 8) for fixing the developer transferred onto the recording medium by applying heat and pressure, and a conveying means (roller 21, roller 21) for conveying the recording medium. 22), a driving unit (motor 5) for driving the fixing unit, and a first speed changing unit (1) for controlling the driving unit to change the fixing conveyance speed when the recording medium passes through the fixing unit. A printer control device 1) and temperature changing means (printer control device 1) for changing the fixing temperature of the fixing means via the lighting circuit 3 based on the fixing conveyance speed are provided, and the printer control device 1 drives the motor 5. When the fixing conveyance speed when the recording medium passes through the fixing device 8 is controlled to be variable, the printer control device 1 changes the fixing temperature of the fixing device 8 based on the fixing conveyance speed to fix the fixing device. While reducing the power consumed,
In addition, it is possible to fix the image transferred onto the recording medium with a uniform amount of heat even if the fixing conveyance speed changes.

In a second aspect of the present invention, the first speed varying means (printer control device 1) has a fixing conveyance speed when the recording medium passes the fixing means when the recording medium passes the fixing means. It is possible to reduce the electric power consumed by the fixing unit by decelerating.

According to a third aspect of the invention, the temperature varying means (printer control device 1) varies the fixing temperature of the fixing means based on the varied fixing conveying speed, and the recording medium is changed even if the fixing conveying speed changes. It is possible to fix the image transferred onto the sheet with a uniform amount of heat.

A fourth invention is the fixing means (fixing device 8).
The discharge medium (discharge roller 23) that discharges the recording medium that has passed through, the discharge driving unit (motor 5) that drives the discharge conveying unit, and the discharge driving unit. A second speed varying unit (printer control device 1) for varying the discharge / transport speed of the recording medium to be discharged and transported is provided, and the excess transport time due to the transport speed decelerated at the time of fixing is compressed and transported as much as possible. It is possible to minimize the change in the total transport time required for.

A seventh aspect of the present invention is provided with a measuring means (measured by the printer controller 1 from the output of the sensor 11) for measuring the distance between each recording medium that is continuously conveyed.
The speed changing means (printer control device 1) changes the fixing conveyance speed when the recording medium passes through the fixing means based on the separation length measured by the measuring means to change the fixing conveyance speed. The recording medium can be conveyed at an optimum conveying speed at which uniform heat is applied to the recording medium continuously conveyed in this state.

FIG. 2 is a flow chart showing a first embodiment of the fixing / conveying control method for the image forming apparatus according to the present invention.
Note that (1) to (7) indicate each step.

First, when the start of the printer is decided, it is judged whether the recording paper S is a standard paper (1),
If it is determined that the paper is not the standard paper, the length of the paper is measured by the sensor 11 or the sensor 12 (2), then it is determined whether or not the paper is continuously fed (3), and it is determined that the paper is continuously fed. Measures the inter-paper length (distance between cut sheets) (4), determines the conveyance speed of the fixing device 8 (5), and changes the speed of the motor 5 (6).

Along with this, the target temperature of the temperature control of the fixing device 8 is changed so that an equal amount of heat can be obtained according to the conveying speed (7).

By carrying out the above control, it is possible to reduce the printing time as a whole while suppressing the electric power of the fixing device.

Further, the electric power of the fixing device can be lowered without increasing the printing time as a whole, and the electric power can be saved.

[Second Embodiment] FIG. 3 is a schematic block diagram illustrating the structure of a recording medium (for example, recording paper) transport mechanism in an image forming apparatus according to a second embodiment of the present invention.
For example, the case of a laser printer is shown. The mechanism and operation will be described below. Note that the difference from the first embodiment is that, downstream of the fixing device 8, a paper discharge sensor 15 for detecting the paper transport state of the paper discharge unit, and a paper discharge roller 2 for discharging the recording paper S
4. A point that a stacking tray (not shown) for stacking the recording sheets S for which recording has been completed is provided.

Correspondence between the present embodiment and each means of the fifth invention and its operation will be described below with reference to FIG.

According to a fifth aspect of the present invention, the second speed varying means (printer control device 1) increases the discharge transport speed from the fixing transport speed, and transport time at the transport speed decelerated during fixing. The excess amount of the above is offset to enable the conveyance while ignoring the deceleration at the time of fixing.

FIG. 4 is a flow chart showing a second embodiment of the fixing / conveying control method for the image forming apparatus according to the present invention.
In addition, (1) to (10) indicate respective steps, and the same steps as those in FIG. 2 are denoted by the same step numbers. Only different processing will be described below.

When the heater control temperature is changed in step (7), the sensor 15 detects the recording paper S (8) and the fixing device 8
When it is determined that the trailing edge of the recording paper S has come off (9), the rotation of the motor 6 that drives the paper discharge roller 24 is accelerated by a specified amount (10), the paper interval is increased, and the paper is discharged.

By performing the above processing, the fixing device 8
It is possible to reduce the time taken as a whole by the transportation speed dropped in step 2 and minimize the change in the total time from sheet feeding to sheet discharging.

[Third Embodiment] FIG. 5 is a flow chart showing a third embodiment of the fixing and conveying control method of the image forming apparatus according to the present invention. Note that (1) to (11) indicate steps, and the same steps as those in FIGS. 2 and 3 are denoted by the same step numbers. Only different processing will be described below.

When the sensor 15 detects the recording paper S in step (9) and determines that the trailing edge of the recording paper S has come out of the fixing device 8, the motor 6 for driving the paper discharge roller 24 is rotated in step ( Motor speed changed in 6) (fixing conveyance speed)
(11), the speed is increased (10), the paper interval is increased, and the sheet is discharged.

By performing the above processing, the fixing device 8
It is possible to reduce the time taken as a whole by the transportation speed dropped in step 1, and to carry out without impairing the total time from sheet feeding to sheet discharging.

[Fourth Embodiment] FIG. 6 is a flow chart showing a fourth embodiment of the fixing and conveying control method for an image forming apparatus according to the present invention. The same steps as those in FIGS. 2, 3 and 4 are designated by the same step numbers. In addition, (1
2) indicates steps, and only different processing will be described below.

When the sensor 13 detects the recording paper S in step (7), the fixing device 8 is entered, and the sensor 14 detects the recording paper S and the fixing device 8 determines the conveying speed of the recording paper S (1
2) If the value is less than the predetermined value, the temperature of the heater temperature control and the lighting cycle are further changed so that the amount of heat applied to the recording paper S becomes constant.

By performing the above processing, the fixing device 8
It is possible to prevent excessive heat from being applied to the recording paper S when the transport speed dropped in step 2 has dropped below a predetermined value. Further, the sensor 15 can also function as the sensor 14. Further, the sensor 13 and the sensor 14 detect and determine the transport speed, but it is also possible to detect and determine the rotational speed of the motor 5 by a speed sensor (not shown).

Correspondence between the present embodiment and each means of the sixth and eighth inventions and their functions will be described below with reference to FIG.

According to a sixth aspect of the invention, the temperature varying means (printer control device 1) variably controls the lighting cycle for lighting the fixing heater of the fixing device 8 via the lighting circuit 3 so that the recording medium becomes excessive. It is possible to reliably control the amount of heat applied to the recording medium by the fixing device 8 so that heat is not applied.

According to an eighth aspect of the invention, the temperature varying means (printer control device 1) changes the varied fixing temperature of the fixing device 8 when the varied fixing conveyance speed changes to a prescribed speed or less. It is possible to prevent excessive heat from being applied to the recording medium.

Correspondence between the present embodiment and each step of the ninth invention and its action will be described below with reference to FIG. 2, FIG. 4 to FIG.

A ninth aspect of the invention is an image forming method of an image forming apparatus having a fixing means for fixing the developer transferred to a recording medium by applying heat and pressure, wherein the fixing conveyance speed when passing through the fixing means is variable. Variable speed process (Figs. 2 and 4)
To each step (6) in FIG. 6 and a temperature changing step (each step (7) in FIGS. 2 and 4 to 6) for changing the fixing temperature of the fixing unit based on the fixing conveyance speed. Thus, it is possible to automate the process of fixing the image transferred to the recording medium with a uniform amount of heat while reducing the power consumed by the fixing unit and even when the fixing conveyance speed changes.

The present invention may be applied to a system composed of a plurality of devices or an apparatus composed of a single device. Further, it goes without saying that the present invention can be applied to the case where it is achieved by supplying a program to a system or an apparatus.

[0059]

As described above, the first aspect of the present invention
According to the invention, when the first speed changing means controls the driving means to change the fixing conveyance speed when the recording medium passes through the fixing means, the temperature changing means operates based on the fixing conveyance speed. Since the fixing temperature of the fixing unit is varied, it is possible to fix the image transferred onto the recording medium with a uniform amount of heat while reducing the power consumed by the fixing unit and changing the fixing conveyance speed.

According to the second aspect of the invention, the first speed varying means reduces the fixing conveyance speed when the recording medium passes the fixing means when the recording medium passes the fixing means. The electric power consumed by the fixing unit can be reduced.

According to the third aspect of the invention, since the temperature changing means changes the fixing temperature of the fixing means based on the changed fixing conveying speed, the temperature is transferred to the recording medium even if the fixing conveying speed changes. An image can be fixed with a uniform amount of heat.

According to the fourth aspect of the invention, the second speed changing means controls the paper discharging drive means to change the paper discharging and conveying speed of the recording medium for discharging and discharging, so that the conveying speed is reduced at the time of fixing. It is possible to minimize the change in the total transport time required for transport by compressing the excess amount of the transport time due to.

According to the fifth aspect of the invention, the second speed varying means speeds up the paper discharge transportation speed more than the fixing transportation speed.
Excessive conveyance time due to the conveyance speed decelerated at the time of fixing can be offset, and the conveyance can be performed while ignoring the deceleration at the time of fixing.

According to the sixth aspect of the invention, the temperature varying means varies the lighting cycle for lighting the fixing heater of the fixing means, so that the fixing means can be applied to the recording medium so that excessive heat is not applied to the recording medium. The amount of heat applied can be reliably controlled.

According to the seventh aspect of the invention, the first speed varying means varies the fixing conveyance speed when the recording medium passes through the fixing means based on the separation length measured by the measuring means. The recording medium can be conveyed at an optimum conveying speed at which uniform heat is applied to the recording medium that is continuously conveyed with the fixing and conveying speed being changed.

According to the eighth aspect of the invention, the temperature varying means changes the varied fixing temperature of the fixing means when the varied fixing conveying speed is changed to the prescribed speed or less, so that excessive heat is generated. It is possible not to join the recording medium.

According to the ninth aspect of the invention, the fixing conveyance speed when passing through the fixing means is varied, and the fixing temperature of the fixing means is varied based on the fixing conveyance speed, so that the electric power consumed by the fixing means is changed. It is possible to automate the process of fixing the image transferred onto the recording medium with a uniform amount of heat, while reducing the amount of heat, and even when the fixing conveyance speed changes.

Therefore, when the fixing conveyance speed is changed, the fixing temperature is variably adjusted to secure the time for the recording medium to exist in the fixing device to obtain heat, and the total amount of heat obtained by the recording paper can be made the same. The printing time can be shortened without raising the electric power of the fixing heater, and further, the electric power of the heater can be lowered without increasing the printing time to reduce the power consumption.

[Brief description of drawings]

FIG. 1 is a schematic block diagram illustrating a recording medium transport mechanism configuration in an image forming apparatus according to a first exemplary embodiment of the present invention.

FIG. 2 is a flowchart showing a first embodiment of a fixing / conveying control method for an image forming apparatus according to the present invention.

FIG. 3 is a schematic block diagram illustrating a recording medium transport mechanism configuration in an image forming apparatus according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing a second embodiment of a fixing / conveying control method for an image forming apparatus according to the present invention.

FIG. 5 is a flowchart showing a third embodiment of a fixing / conveying control method for an image forming apparatus according to the present invention.

FIG. 6 is a flowchart showing a fourth embodiment of a fixing / conveying control method for an image forming apparatus according to the present invention.

[Explanation of symbols]

 1 Printer Control Device 2 Drive Circuit 3 Lighting Circuit 4 Motor 5 Motor 8 Fixer 11 Sensor 12 Sensor S Recording Paper

Claims (9)

[Claims] 1. An image forming apparatus comprising a fixing unit for fixing a developer transferred onto a recording medium by applying heat and pressure,
A transport unit for transporting the recording medium, a drive unit for driving the fixing unit, and a first speed variable that controls the drive unit to vary a fixing transport speed when the recording medium passes through the fixing unit. An image forming apparatus comprising: a fixing unit and a temperature changing unit that changes a fixing temperature of the fixing unit based on the fixing conveyance speed. 2. The first speed varying means reduces the fixing transport speed when the recording medium passes the fixing means when the recording medium passes the fixing means. 1. The image forming apparatus according to 1. 3. The image forming apparatus according to claim 1, wherein the temperature changing unit changes the fixing temperature of the fixing unit based on the changed fixing conveyance speed. 4. A paper discharge conveyance unit for discharging and conveying the recording medium that has passed through the fixing unit, a paper discharge drive unit for driving the paper discharge conveyance unit, and a paper discharge control unit for controlling the paper discharge drive unit. A second method for varying the discharge / transport speed of the recording medium to be transported
2. The speed varying means according to claim 1 is provided.
The image forming apparatus described. 5. The image forming apparatus according to claim 4, wherein the second speed varying unit increases the discharge transport speed from the fixing transport speed. 6. The image forming apparatus according to claim 1, wherein the temperature varying unit varies a lighting period for lighting the fixing heater of the fixing unit. 7. A measuring means for measuring a separation distance from each recording medium that is continuously conveyed is provided, and the first speed varying means sets a fixing conveyance speed when the recording medium passes through the fixing means. The image forming apparatus according to claim 1, wherein the distance is variable based on the distance measured by the measuring unit. 8. The temperature varying means changes the varied fixing temperature of the fixing means when the varied fixing conveying speed is changed to a prescribed speed or less.
The image forming apparatus described. 9. An image forming method of an image forming apparatus comprising a fixing means for fixing a developer transferred to a recording medium by applying heat and pressure, wherein a speed changing step of changing a fixing conveyance speed when passing through the fixing means. And a temperature changing step of changing the fixing temperature of the fixing unit based on the fixing conveyance speed.