JPS63121880A - Fixing device - Google Patents

Abstract

PURPOSE:To prevent recording paper from deforming by performing flash irradiation while synchronizing the conveyance period of recording paper conveyed periodically to a fixing device with the light emission period of a flash lamp. CONSTITUTION:A paper feed roller 6 rotates until one sheet of recording paper is placed on a conveyance path 14, then stops for a constant time, and rotates again until the next sheet of recording paper is placed on the conveyance path repeatedly. The recording paper 7 is conveyed at specific speed, so one sheet of recording paper is constant in the time from the start of the rotation of the paper feed roller 6 for placing the recording paper on the conveyance path to the arrival at the flash lamp 1 and the output of a paper feed timer circuit 4 is supplied as a 1st timing signal to a delay circuit 3 which delays the signal by the time and the output of it is supplied as a 2nd timing signal to the light emission control circuit 17 for a light emitting circuit 3 through an input terminal 18, so that the lamp 16 emits light only when the recording paper 7 moves to right below the flash lamp. Consequently, the recording paper is prevented from deforming owing to the heating of a conveying device.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a fixing device for recording images using toner in printers, facsimile machines, etc., and particularly to a fixing device for efficiently obtaining a fixed toner image using cut paper. The present invention relates to a fixing device suitable for.

[Conventional technology]

As a fixing device used in printers, facsimile machines, etc., it is known that toner powder is used for the image, a recording method using electrostatic force is used for development, and the toner image is heated and fixed by flashing light from a xenon flash lamp etc. for fixing. ing.

In this type of fixing device, it is desired to efficiently supply fixing energy.

In conventional fixing devices of this type, even if the recording paper suddenly disappears in the fixing section during printing, a flash energy equivalent to the energy required for fixing is irradiated. in this case,
This causes inconveniences such as wasting power and heating the recording paper conveying device. In order to solve this problem, a fixing device is also known which is equipped with a recording paper detecting means and detects that no recording paper is present in the fixing section and stops the flash irradiation. However, even in such an apparatus, depending on the detection timing, there is no guarantee that the flash light equivalent to the fixing energy will not be irradiated at all on the area where there is no recording paper, and usually the flash light will be irradiated once or more and then stopped. Therefore, although the above-mentioned inconveniences are reduced, they are not completely eliminated, and similar inconveniences still exist, albeit to varying degrees. This is because the conventional apparatus deals only with continuous paper, so the absence of recording paper is detected as an abnormality. When such an abnormality occurs, not only the irradiation is stopped, but also the abnormality occurrence display means is activated, the driving of the conveyance device is also stopped, and depending on the case, the driving of the developing drum and the developing device is also stopped. Therefore, printing becomes impossible and it is necessary to perform some kind of manual operation to recover.

When cut paper is used in the conventional flash fixing device described above, there is always a portion where there is no recording paper between one recording paper and the next recording paper, so the above-mentioned inconvenience occurs for each recording paper. Therefore, there are problems in that power is wasted, the conveying device heats up and deforms the recording paper, and sometimes there is a risk of fire. In the case of a fixing device equipped with a recording paper detection means, in addition to the above-mentioned drawbacks, the abnormality occurrence display means is activated and the drive of the conveying device is stopped even though there is no situation that the user should recognize as abnormality. There is also the inconvenience that means for dealing with the occurrence of an abnormality, such as a failure, is activated and printing becomes impossible.

Furthermore, there is also a known recording apparatus that synchronizes the drive signal of a pulse motor that runs the recording paper at variable speeds with the flash irradiation timing to prevent wasted power. An example of this type of fixing device is disclosed in Japanese Patent Publication No. 60-49309. However, in the case of cut paper printing, the pulse motor described above continuously conveys the cut paper, so its drive signal does not have a marker that indicates the gap between the recording papers. Even when printing is performed, the above-mentioned inconveniences similarly occur.

[Problem that the invention seeks to solve]

The above conventional technology does not take into consideration the flash fixing of cut paper prints, which wastes power, heats the conveying device, deforms the recording paper, poses a risk of fire, and also causes abnormalities. However, there was a problem in that the countermeasures were activated and printing became impossible.

An object of the present invention is to eliminate waste of power, to fix a plurality of cut sheets or more continuously without heating the conveying device, and without deforming the recording paper.

[Means for solving problems]

J-, the purpose is achieved by synchronizing the conveyance cycle of the recording paper that is periodically conveyed to the fixing device and the light emitting cycle of the flash lamp and irradiating it with flash during continuous printing of multiple sheets of cut paper. .

[Effect]

A recording paper feeding clock and recording paper detecting means provided in the conveyance device output a signal synchronized with the recording paper conveyance cycle. In synchronization with this, the flash lamp is emitted a predetermined number of times depending on the length of the recording paper in the conveying direction, so there is no possibility of irradiating a flash between one recording paper and the next recording paper.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1-4. FIG. 1 is a cross-sectional side view of the recording apparatus of the present invention.
is a flash lamp, 2 is a light emitting circuit, 3 is a delay circuit, 4
5 is a paper feed timer circuit, 5 is a paper feed drive signal circuit, 6 is a paper feed roller, 7 is a recording paper that is cut into a predetermined length and becomes a cut paper, 8 is a paper feed stacker that is a recording paper holding means, 9 is a recording paper transport roller, 10 is a recording paper transport tractor, 11 is a transfer device, 12 is a photosensitive drum, J3 is a paper discharge stacker, I
Zl is the conveyance path. A paper feed timer circuit 4, a paper feed drive signal circuit 5, and a paper feed roller 6 constitute recording paper selection means. Further, the recording paper conveyance roller 9 conveyance path 14 constitutes a recording paper conveyance means. Figure 2 is a circuit diagram of the light emitting circuit 3.
1 is a lamp, 16 is a light emission trigger signal switch, 17 is a light emission control circuit, and 18 is an input terminal. FIG. 3 is a cross-sectional side view of the flash lamp 1, and 19 is a reflecting plate. FIG. 4 shows the output signals of each circuit, K is paper feed timer circuit 4,
L is an output signal of the paper feed drive signal circuit 5, M is an output signal of the delay circuit 3, and N is an output signal of the light emission control circuit 17. Further, a indicates the stop time of the paper feed roller 6, b indicates the rotation time, and C indicates the delay time of the delay circuit. In FIG. 1, the recording paper 7 is placed on the conveyance path 14 closest to the paper feed stacker 8 by the paper feed roller 6, and then transferred to the conveyance roller 9, the other conveyance paths 14, and the conveyance tractor 1.
0, it is transported at a constant speed. During this time, the recording paper 7 is developed with toner as an unfixed image on the recording paper 7 by the transfer device IJ, and then reaches the flash lamp 1, where the recording paper 7 is irradiated with flash light a predetermined number of times, for example, - times.
Toner is fused and fixed on the paper and stored in the discharge stacker 13. The recording paper 7 in this embodiment is A4 size,
It is 8.5 inches long in the transport direction. It also has a continuous printing mode, and during continuous printing, the gap between the recording sheets is maintained at a constant length that is longer than the fixing length of one lamp. Therefore, the paper feed roller 6 feeds one sheet of recording paper to the transport path 1.
After rotating until the next recording paper is placed on the transport path, the rotation is stopped for a certain period of time, and the operation is repeated until the next recording paper is placed on the conveyance path. In addition, during this time, the conveyance roller 9 and the conveyance tractor 1
0 continues to rotate at a constant speed. The paper feed roller 6 is repeatedly rotated by a pulse motor (not shown), and its rotation is controlled by a drive signal output from the paper feed drive signal circuit 5. The signal on which the paper feed drive signal circuit 5 is based is a square wave with a constant period output from the paper feed timer circuit 4. Here, since the recording paper 7 is conveyed at a predetermined speed, for example, a constant speed, if we focus on a single sheet of recording paper, the recording paper starts to rotate after the paper feed roller 6 starts rotating to put the recording paper on the conveyance path. The time it takes to reach flash lamp 1 is constant (J2). Therefore, the output of the paper feed timer circuit 4 is used as a first timing signal and input to a delay circuit 3 that delays it by that time, and the output of the delay circuit is used as a second timing signal as shown in FIG. 2 of the light emitting circuit 3. If input is made to the light emission control circuit 17 through the input terminal 18, the lamp 15 will emit light only when the recording paper 7 is just below the flash lamp, as shown in FIG.

Here, the light emission signal trigger switch 16 is the light emission control circuit 17.
It closes only when a +5V signal is input from the lamp 15, and the three lamps 15 emit light at the same time. Each of the signals mentioned above is the fourth signal.
It is as shown in the figure.

Further, as shown in FIG. 3, the fixing range of the fixing device 1 is set to, for example, 8.5 inches by adjusting the reflector 19, which exactly matches the length of A4 recording paper in the conveying direction. Therefore, according to the light emitting procedure of this embodiment described above, the gap between the recording sheets is not irradiated with flash light, and even if it is irradiated, the light is weak enough to not have the energy necessary for fixing. Therefore, the conveyance tractor does not heat up and there is no waste of electricity. In the embodiment shown in FIG. 1, three lamps 15 are used, but one lamp may be used to emit light three times in synchronization with the conveyance, or the light may be flashed over the entire recording paper. However, there are no particular limitations.

FIG. 5 is a cross-sectional side view of a recording apparatus according to another embodiment of the present invention, in which numeral 20 denotes a recording paper detector serving as recording paper detection means. The recording paper detector 20 is attached to the lower surface of the transport path 14 at the position closest to the fixing device 1 between the fixing device 1 and the paper feed roller 6 in the transport path 1.4, and detects whether the recording paper is being recorded by an optical sensor. When it is on the paper detector 20, it outputs a +5V signal, and when it is not there, it outputs an Ov signal. As a result, the recording paper detector 2
The output of 0 is similar to the output of the paper feed timer circuit 4 with a time delay. In this embodiment, the output of the paper feed timer circuit 4 is not input to the delay circuit 3, but instead, the output of the recording paper detector 20 is input as the first timing signal. The rest of the structure is the same as the embodiment shown in FIG.

At this time, the delay time of the delay circuit 3 is set in accordance with the time from when the recording paper passes through the recording paper detector 20 until it reaches directly below the fixing device 1. Therefore, as in the first embodiment, there is an effect that only the recording paper is irradiated with flash light. In addition, when the output of the paper feed timer circuit 4 is used as the input of the delay circuit 3, even if a problem occurs in which the recording paper does not reach the fixing device]-5 due to a jam or the like during conveyance of the recording paper, the lamp]-5 emits light, but the recording paper detector 2 of this embodiment
If the method of inputting the output of 0 to the delay circuit 3 is used, the flash lamp will not emit light unless the recording paper reaches the recording paper detector 20, so the effect is that the flash irradiation will be automatically stopped when the above trouble occurs. There is.

Hereinafter, the case where only A4 size recording paper is printed has been described, but next, another embodiment in which printing on both A4 and A3 size recording paper is possible will be described.

This embodiment is equipped with a changeover switch that allows the operator to select either A3 or A4 size. The rest of the configuration is the same as that shown in FIG. 1, and the gap between the recording sheets is also constant for printing on A3-size recording paper and for printing on A4-size recording paper, which is the same as in the embodiment shown in FIG. It is similar to that. In the case of A3 size recording paper, the length in the recording paper conveying direction is 1 inch, which is twice as long as that of A4 size recording paper. Therefore, in the case of printing on A3 size recording paper, the time of the convex portion of the square wave, which is the basis of the rotation time of the paper feed roller 6 in the output of the paper feed timer 4, is twice that of printing on A4 size recording paper. The output signal of the light emission control circuit] 7 is such that while a sheet of recording paper passes through the fixing device 1, the flash lamp 15 first emits light once as in the case of printing on A4 size recording paper, and then the 8.5 inch It is set to emit light twice in total, such as once after being transported.

FIG. 6 is a diagram showing the output signals of each circuit during printing on A3 size recording paper, and the symbols are the same as those in FIG. 4.

In this embodiment, when the operator specifies the A4 size recording paper printing mode, the output waveform is as shown in FIG.
The paper feed timer 4 and the light emission control circuit 17 are provided with two output formats so that the output waveform shown in FIG. 6 is obtained when the paper size printing mode is specified. According to this embodiment, it has the same effect as the embodiment shown in FIG. 1, and also has the advantage of being able to print on both A4 size recording paper and F3 size recording paper. Furthermore, if the same paper feed timer circuit 4 and light emission control circuit]-7 as in this embodiment are used and the configuration of the apparatus is the same as in the embodiment shown in FIG. 5, A4 size recording paper and A3 size recording paper It is possible to perform both types of printing, and in the event that a problem such as a jam occurs before the recording paper reaches the recording paper detector, the flash lamp will automatically stop emitting light.

FIG. 7 is a sectional side view of a flash fixing device according to another embodiment of the present invention. FIG. 7(a) shows the case of printing on A3 size recording paper, and FIG. 7(b) shows the case of printing on A4 size recording paper.
The shape of 9 changes depending on each case, and the fixing range is 1 inch in the case of FIG. 7(a) and 8.5 inches in the case of FIG. 7(b). In this way, if a member whose shape changes depending on the applied voltage is used for the reflection plate 19, the A3
It is possible to fix both A4 size and A4 size recording paper with one light emission, and the output mode of the light emission control circuit can be set to ]-mode.

[Effects of the Invention] As described above, according to the present invention, when printing a plurality of continuous cut sheets, there is hardly any flash irradiation between one recording sheet and the next recording sheet, so there is no wastage of power. This has the effect of preventing deformation of the recording paper due to heating of the conveying device.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional side view of a recording device according to an embodiment of the present invention, FIG. 2 is a light emitting circuit diagram of the present invention, FIG. 3 is a cross-sectional side view of a flash fixing device of the present invention, and FIG. 4 is a cross-sectional side view of a recording device according to the present invention. FIG. 5 is a cross-sectional side view of a recording device according to another embodiment of the present invention, and FIG. 6 is a diagram showing the output waveforms of each circuit when printing on A4-sized recording paper according to the present invention. Output waveform diagram, 7th
The figure is a sectional side view of a flash fixing device according to another embodiment of the present invention. 1... Flash fixing device, 2... Light emitting circuit, 3...
... Delay circuit, 4... Paper feed timer circuit, 5... Paper feed drive signal circuit, 6... Paper feed roller, 7... Recording paper, 9... Recording paper conveyance roller, 10. ... Recording paper transport tractor, 14... Transport path, 15... Flash lamp, 17... Light emission control circuit, 20... Recording paper detector.

Claims (1)

[Claims] 1. Recording paper holding means for holding a plurality of recording papers cut into predetermined lengths; and a recording paper selection unit for selecting one of the plurality of recording papers based on a predetermined timing signal. a recording paper conveyance means for conveying the selected recording paper at a predetermined speed; and a flash lamp that emits light a predetermined number of times using the predetermined timing signal as an index to fuse toner to the selected recording paper. A fixing device comprising: 2. Recording paper holding means for holding a plurality of recording papers cut into predetermined lengths; Recording paper selection means for selecting one of the recording papers according to a first timing signal; and the selected recording paper. a recording paper transport means for transporting the selected recording paper at a predetermined speed; a flash lamp that emits light a predetermined number of times based on a second timing signal to fuse the toner to the selected recording paper; and a delay circuit that generates the second timing signal by delaying the selected recording paper according to the time during which the selected recording paper is transported from the recording paper holding means to the flash lamp by the recording paper transporting means. Features a fixing device. 3. A recording paper transport means that transports the recording paper cut into a predetermined length at a predetermined speed, and a recording paper detection unit that outputs a detection signal depending on the presence or absence of the recording paper that is transported at the predetermined speed. A fixing device comprising: a flash lamp that emits light a predetermined number of times using the detection signal as an index to fuse toner to the recording paper. 4. A recording paper transport means for transporting recording paper cut to a predetermined length at a predetermined speed, and detecting the presence or absence of the recording paper being transported at the predetermined speed and outputting a first timing signal. recording paper detection means; a flash lamp that emits light a predetermined number of times based on a second timing signal to fuse toner to the recording paper; A fixing device comprising: a delay circuit that generates the second timing signal with a delay depending on the time during which the recording paper is conveyed from the recording paper detection means to the flash lamp. 5. Recording paper holding means for holding a plurality of recording papers of different lengths, each cut to a predetermined length; input means for allowing a user to specify the length of the recording paper; recording paper selection means for selecting one based on a predetermined timing signal and data received from the input means; recording paper transport means for transporting the selected recording paper at a predetermined speed; A fixing device comprising: a flash lamp that emits light a predetermined number of times using a signal and data received from the input means as an indicator to fuse toner to the selected recording paper. 6. Recording paper holding means for holding a plurality of recording papers of different lengths and each cut to a predetermined length; input means for allowing the user to specify the length of the recording paper; and a first timing signal; recording paper selection means for selecting one of the recording papers according to data received from the input means; recording paper transport means for transporting the selected recording paper at a predetermined speed; and a second timing signal. and a flash lamp that emits light a predetermined number of times based on data received from the input means to fuse toner to the selected recording paper; A fixing device comprising: a delay circuit that generates the second timing signal with a delay according to the time during which the recording paper is transported from the recording paper holding means to the flash lamp by a paper transporting means. 7. The fixing device according to any one of claims 1 to 6, wherein the predetermined speed is a substantially constant speed. 8. The fixing device according to any one of claims 1 to 6, wherein the predetermined number of times is determined depending on the length of the recording paper in the conveyance direction. 9. Claim 1 is characterized in that the flash lamp is a flash lamp that emits light a predetermined number of times in synchronization with the predetermined timing signal to fuse toner to the selected recording paper. fixing device. 10. In claim 5, the flash lamp emits light a predetermined number of times in synchronization with the predetermined timing signal according to data received from the input means, and the flash lamp emits light a predetermined number of times in synchronization with the predetermined timing signal, and A fixing device characterized by being a flash lamp that fuses toner to paper. 11. In claim 6, the flash lamp emits light a predetermined number of times in synchronization with the second timing signal according to the data received from the input means, and A fixing device characterized by being a flash lamp that fuses toner to recording paper.