JPH056188B2 - - Google Patents

Description

[Detailed description of the invention] Technical field The present invention relates to an image forming apparatus that forms an image.

Conventionally, in image forming apparatuses such as copying machines, a so-called roller fixing method is used, in which paper onto which toner has been transferred is sandwiched between a heated heating roller and a pressure roller, and the toner is fused and discharged. is often adopted. Here, when an interruption occurs during continuous copying, such as a paper jam, the copying machine user opens the designated doors (front door and paper ejection section door), removes the paper, etc., and closes the rear door. Action must be taken. However, in the past, it was difficult to
Regardless of the jam processing, the heating roller is always heated, and copying cannot be started until the next maximum fusing temperature is reached, and if jams occur frequently, this so-called wait time accumulates and becomes extremely difficult. The drawback was that it took time.

Purpose In view of the above points, an object of the present invention is to provide an image forming apparatus that eliminates the above drawbacks.

Furthermore, another object of the present invention is to enable an image forming apparatus to immediately execute an image forming mode after the image forming mode is interrupted.

Summary of the Invention The present invention, which achieves the above objects, includes an image forming means for forming an unfixed image on a recording material, a fixing means having a heating member for heating and fixing the unfixed image, and a jam for detecting a jam on the recording material. a detection means; a jam processing end detection means for detecting the end of the jam processing;
A power switch of the apparatus, and a jam detecting means which puts the apparatus in a wait state until the heating member reaches a first set temperature from the power switch, and when the heating member reaches the first set temperature, puts the apparatus into a state ready for image formation. an image forming apparatus comprising: a control means for turning off electricity to the heating member when a jam of the recording material is detected; and a control means for starting electricity to the heating member when the jam processing end detection means detects the end of the jam processing; When the heating member is reenergized after the jamming process is completed, if the temperature of the heating member is below the second set temperature, which is lower than the first set temperature,
The apparatus is placed in a wait state until the heating member reaches the first set temperature, and when the first set temperature is reached, the apparatus is placed in an image forming ready state, and when the temperature is equal to or higher than the second set temperature, the apparatus is placed in a wait state. This feature is characterized in that an image can be formed without any trouble.

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

FIG. 1 is a sectional view of a copying machine to which the present invention is applied, and its structure and operation will be explained.

Reference numeral 1 denotes a photosensitive drum which is rotated in the direction of the arrow by a motor (not shown). The original placed on the original table glass 36 is illuminated by the illumination lamp 23 that is integrated with the first scanning mirror 24, and the reflected light is scanned by the first scanning mirror 24 and the second scanning mirror 25. . The first scanning mirror 24 and the second scanning mirror 2
5 is a lens 30 by moving at a speed ratio of 1:1/2.
The document is scanned while the optical path length in front of the document is always kept constant.

The reflected light image passes through the zoom lens 30 and the third mirror 26, and then forms an image on the drum 1 at the exposure section. Note that 2 is a blank exposure lamp.

The drum 1 is uniformly charged by a primary charger 3, and an electrostatic latent image is formed thereon by image exposure. The electrostatic latent image on the photosensitive drum 1 is then developed by a developing roller 13' of a developing device 13.
The toner image is visualized as a toner image, and the toner image is transferred onto transfer paper by the transfer charger 4. The transfer paper in the cassette 10 is fed into the machine by a paper feed roller 11, and is sent toward the photosensitive drum 1 by a register roller 15 with accurate timing. At this time, the leading edge of the latent image and the leading edge of the paper are aligned at the transfer section. In the transfer section, a transfer charger 4 performs corona discharge from behind the transfer paper to electrostatically transfer the toner onto the transfer paper. Next, an AC corona or a separation charger 5 having a polarity opposite to that of the transfer charger 4 neutralizes the charge on the back surface of the transfer paper, separates the transfer paper from the photosensitive drum 1, and places it on a conveyor belt 6 for conveyance. do. After the transfer paper has been separated, the photosensitive drum 1 is neutralized by a pre-cleaner static eliminator 7, and then the untransferred toner remaining on the photosensitive drum 1 is removed from the surface of the photosensitive drum 1 by a cleaner 8. . Meanwhile, the transfer paper passes through a fixing device 9, on which the toner image is permanently fixed. Note that 38 is a fixing roller, and 39 is a temperature sensor.

Figure 2 controls the entire sequence of the copier.
3 is a control block diagram of the CPU 100. FIG. 101 is a display and operation unit, 102 is a paper sensor, and 103 is a jam sensor.
The CPU 100 is connected via a driver 110 to a main motor 105, a paper feed roller drive clutch, a fixing heater 107, and a register roller drive clutch 10.
2. Send an output signal to the optical system clutch 109, etc. FIG. 3 shows a copying machine control flowchart including jam processing by the CPU 100. First, if the power is turned on in step a, the fixing heater is turned on. If the heating roller surface temperature is 150°C or higher in step b, the fixing roller rotates, and when it reaches 180°C, the fixing roller stops.
Next, if the copy button is turned on in step c, copying starts by starting the main motor. If no jam occurs in step d, the copy sequence ends in step e, the main motor stops if copying is not to be continued, and the copying program ends if the power is not turned on.
If the power is on, the process advances to step c and waits for input of the copy button. or,
In the case of continuous copying, the process proceeds to step f, and if the heating roller surface temperature is 150 DEG C. or higher, copying is started and continued at step c.
However, if the heating roller surface temperature is below 150°C, the main motor is stopped and the heating roller surface temperature is raised to 180°C in step b.

Next, if a jam occurs in step d, the fixing heater is turned on after the jam processing is completed in step g. If the fixing heater has been turned off for more than 5 minutes in step h, the heating roller surface temperature is clearly 150.
Since the temperature is below 180°C, the temperature is raised again to 180°C in step b in the same manner as above. Also, step h
If the fuser heater is off for less than 5 minutes, the temperature is sensed in step i and the temperature is set to 150℃.
If this is the case, the process advances to step c, where it waits for input of the copy button. However, 150℃
If it is less than 180℃, repeat step B as above.
rise to.

FIG. 4 shows a temperature curve according to the sequence of fixing temperature control according to the present invention. Note that the dashed line is a conventional sequence line. In Figure 4,
Assuming that a jam occurs at certain points E and E' between C and D, and then the jam process ends at points F and F', the temperature of the heating roller is measured immediately after this process, and this temperature is sufficient for fixing. If the temperature is above the minimum temperature, copying is enabled immediately. Alternatively, a certain period of time t ₁ is determined in advance, and copying is possible immediately if the time from the time when the power is turned off due to a jam until the time when the power is turned on again is within t ₁ .

In the case of the conventional sequence, copying cannot be performed between (l ₁ +l ₂ ), (E-F), and (E'-F') shown in FIG. 4 after jamming. Users may make hundreds of copies, but in reality, the number of copies is extremely small. The most common continuous copy is about 10 to 100 sheets. Accordingly
In addition to the jam processing time, the time loss between (l ₁ + l ₂ ) described above is a considerable resistance for users. When using the sequence according to the invention, E-F,
The only time loss required is the jam processing time between E' and F', and as is clear from FIG. 4, this time is the same for both the conventional sequence and the sequence according to the present invention. However, as is clear from FIG. 4, when the sequence of the present invention is used, the heating roller surface temperature decreases and approaches the minimum fixable temperature (150° C.). Therefore, Figure 4 G
The sequence is such that when the lowest fixable temperature (150° C.) is detected, copying is disabled, that is, the printer enters a wait state.
However, this l ₃ between GDs cannot be copied, but as mentioned above, this situation rarely occurs.

The heating roller of the fixing device having the temperature curve used in Fig. 4 is φ40, Al wall thickness is 9 mm, Teflon coat is 30μ, and the heater is 850W.The pressure roller is φ40,
It uses SUS and silicone rubber coated 6mm thick.

Effects As detailed above, according to the present invention, even if the process is interrupted due to jamming, after restarting, it is possible to immediately obtain copy paper with good fixing properties without having to wait for a wait each time.
Furthermore, there is an effect that the power supply capacity can be small.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a copying machine to which the present invention is applied. FIG. 2 is a control block diagram of the CPU 100 that controls the entire sequence of the copying machine. Third
The figure is a copying machine control flowchart including jam processing. FIG. 4 is a diagram showing a temperature change curve according to the fixing temperature control sequence according to the present invention. 9 is a fixing device, 38 is a fixing roller, 39 is a temperature sensor, 105 is a main motor, 103 is a jam sensor, and 100 is a CPU.

Claims (1)

[Scope of Claims] 1. An image forming device that forms an unfixed image on a recording material, a fixing device that has a heating member that heats and fixes the unfixed image, a jam detection device that detects a jam on the recording material, and a jam detection device that detects a jam on the recording material. A jam processing end detection means for detecting the end of processing, a power switch of the apparatus, and a wait state of the apparatus until the heating member reaches a first set temperature from this power switch, and the heating member reaches the first set temperature. Then, the apparatus is brought into an image forming state, and when the jam detection means detects a jam on the recording material, the heating member is turned off, and when the jam processing end detection means detects the end of the jam processing, the control means starts energization of the heating member. In the image forming apparatus, the control means is configured to: when the heating member is re-energized after the jamming process, if the temperature of the heating member is at a second set temperature or lower, which is lower than the first set temperature, the control means: The apparatus is placed in a wait state until the heating member reaches the first set temperature, and when the first set temperature is reached, the apparatus is placed in an image forming ready state, and when the temperature is equal to or higher than the second set temperature, the apparatus is placed in a wait state. An image forming apparatus characterized in that an image forming apparatus can be brought into a state in which an image can be formed without any trouble.