JPH0339772A - System for controlling flash fixation - Google Patents

Abstract

PURPOSE:To prevent an unnecessary action for flash fixation by controlling the action for the flash fixation in a flash fixation part based on the output of a detecting means for detecting a cut medium. CONSTITUTION:The system is provided with an image forming part 1 for forming a powder image on the cut medium CP and the flash fixation part 2 for performing the flash fixation of the powder image on the conveyed cut medium CP. And a detecting means 4 for detecting the cut medium CP is disposed on an upstream side in the conveying direction of the flash fixation part 2 and a control part 5 for controlling the flash fixation in the flash fixation part 2 based on the detection output of the detecting means 4 is disposed. Thus, the flash fixation is performed when the cut medium actually arrives at the flash fixation part, so that the useless emission of the flash light is prevented.

Description

[Detailed description of the invention] [Table of contents] Overview Industrial field of application Prior art (Figure 6) Means for solving the problem to be solved by the invention (Figure 1) Working example (a) 1 Description of Examples (Figures 2 to 5) (b)
Description of other embodiments Effects of the invention [Summary] Regarding a flash fixing control method that fixes a powder image on a cut medium by emitting a flash lamp, unnecessary flash fixing operation is prevented when a cut medium is used. In an image forming apparatus, the image forming apparatus has an image forming section that forms a powder image on a cut medium, and a flash fixing section that flash fixes the powder image on the cut medium being conveyed. A detection means for detecting the cut medium and a control section for controlling the flash fixing of the flash fixing section based on the detection output of the detection means are provided on the upstream side of the section in the conveyance direction.

[Industrial application field]

The present invention enables the flash lamp to emit light.
The present invention relates to a flash fixing control method for fixing a powder image on a cut medium.

In an electrophotographic device or an electrostatic recording device, a formed electrostatic latent image is developed into a powder image using a powder developer.

A flash fixing device is used to fix the powder image on the medium using flash light from a flash lamp.

In such a flash fixing device, it is desired that the flash fixing operation can be performed stably even when cut media such as cut paper is used.

[Conventional technology]

FIG. 6 is an explanatory diagram of the prior art.

The powder image formed on the photosensitive drum 10 of the image forming section l is transferred onto the paper CP, and the powder image on the paper CP is flash-fixed by the flash fixing section 2.

Conventionally, continuous paper was used as the paper CP, and flash fixing was controlled by generating an ON signal for the flash lamp of the flash fixing unit 2 in synchronization with the transport motor that drives the transport roller 3 that transports the paper CP. .

[Problem that the invention attempts to solve]

Incidentally, in addition to continuous paper, more and more devices are using cut paper as paper CP.

When cut paper is used in this way, unlike continuous paper, even if the conveyance motor is rotating, the cut paper does not necessarily reach the flash fixing unit 2.

For this reason, if the flash lamp ON signal is generated in synchronization with the conveyance motor as in the past, the flash lamp will emit light even when there is no cut paper in the flash fixing section 2, which is a waste of energy. In addition to the problems, since the flash lamp is emitted even though it is not necessary, it not only causes an upper temperature limit inside the device, but also causes a rise in the temperature of the parts facing the flash lamp (such as the conveyance roller).
There is a problem in that the life of the flash lamp is shortened.

Therefore, an object of the present invention is to provide a flash fixing control method that can prevent unnecessary flash fixing operations when cut media are used.

[Means to solve the problem]

FIG. 1 is a diagram showing the principle of the present invention.

As shown in FIG. 1, the present invention includes an image forming section 1 that forms a powder image on a cut medium CP, and a flash fixing section 2 that flash fixes the powder image on the cut medium CP that is being transported. In the image forming apparatus, there is provided a detection means 4 for detecting the cut medium CP on the upstream side of the flash fixing section 2 in the conveyance direction, and a flash fixing control of the flash fixing section 2 based on the detection output of the detection means 4. A control section 5 is provided.

[Effect]

In the present invention, by controlling the flash fixing operation of the flash fixing section 2 based on the output of the detection means 4, the flash lamp is caused to emit light when the cut medium CP actually arrives and reaches the flash fixing section 2. That's what I do.

Therefore, unnecessary light emission from the flash lamp can be prevented, thereby preventing wasted energy, causing no increase in temperature, and preventing shortening of the lifespan of various parts.

〔Example〕

(a) Description of one embodiment FIG. 2 is a configuration diagram of an embodiment of the present invention.

In the figure, the image forming section 1 is composed of an electrophotographic printing section and has the following configuration.

The photosensitive drum 10 is made of a photoconductive material such as OPC, and is rotated in the direction of the arrow.The front charger 11 charges the photosensitive drum 10.The image exposure section 1
2 is composed of a pair of LED arrays 12a and 12b, which performs image exposure on the photosensitive drum 10, and the developing device 13 is
It develops the electrostatic latent image on the photosensitive drum 10 with a powder developer, and has a pair of developing rollers 130 and 131, and the transfer charger 14 transfers the powder image on the photosensitive drum 10 onto paper. The static eliminator 15 is a photosensitive drum l.
The cleaner 16, which removes static electricity from O, is the photosensitive drum 10.
It is for cleaning.

The flash fixing unit 2 is composed of four flash lamps, which emit light simultaneously at - degrees to irradiate a predetermined area with flash.

The paper transport unit 3 transports the cut paper along a predetermined transport bus, and includes transport rollers 30 and 31, a standby roller 32 that waits the paper in front of the transfer charger 14, and a standby roller 32 that waits the paper in front of the transfer charger 14, and exposes the transferred paper to light. A peeling port 33 that peels the paper from the drum 10 and conveys it, and a guide plate 34 that guides the peeled paper.
and an introduction roller 3 that introduces the paper into the flash fixing section 2.
5, a suction conveyance section 36 that faces the flash fixing section 2 and suctions and conveys the paper, and a discharge roller 37.

On the paper conveyance path, there are paper sensors 4a to 4a for detecting paper.
4c is provided.

The write timing sensor 4a detects the paper and
The fixing timing sensor 4b, which is used to create write (image exposure) timing for the D arrays 12aS and 12b, is provided between the transfer charger 14 and the flash fixing section 2, detects the paper, and detects the timing of the flash fixing section 2. ejection sensor 4c for creating the flash emission timing.
is for detecting the ejection of paper from the flash fixing section 2.

Briefly explaining the operation of the above configuration, when a cut sheet is conveyed and detected by the write timing sensor 4a, L
The ED arrays 12a and 12b perform writing and form an electrostatic latent image on the photosensitive drum 10.

The cut paper is further conveyed, and after waiting for a predetermined time by the standby roller 32, the cut sheet is conveyed by the standby roller so as to be synchronized with the powder image on the photosensitive drum 10 developed by the developing device 13, and the powder is transferred by the transfer charger I4. The image is transferred.

The photosensitive drum 10 is neutralized by a static eliminator 15 and cleaned by a cleaner 16 .

On the other hand, the cut paper is peeled off by a peeling roller 33 and conveyed along a guide plate 34.

When the fixing timing sensor 4b detects cut paper,
As will be described later, a fixing timing signal is created to control the flash fixing section 2.

The cut paper is flash-fixed while passing through the flash fixing section 2 by an introduction roller 35 and a suction conveyance section 36, and is then discharged by a discharge roller 37.

FIG. 3 is a block diagram of an embodiment of the present invention.

The control section 5 includes a main control section 5a and a signal generation circuit 5b.

The main control unit 5a is composed of a microprocessor (MPU), and receives a paper detection signal P from the fixing timing sensor 4b.
In response to S, a fixing instruction signal X0NO is sent to the signal generation circuit 5b.
K and a charge-on instruction signal CHONM are generated.

The signal generation circuit 5b outputs a charge-on signal *CHON to the power a [6, which will be described later], and after a certain period of time T1 has elapsed, *CH
The ON signal is turned off and a trigger signal TRG is generated.

6a to 6d are flash lamp drive circuits, which include a charging circuit consisting of a capacitor C and an inductance L connected to the flash lamp 20;
It has a trigger transformer Tr connected to the trigger electrode 21 of 0.

6 is a power supply, which charges the capacitors C of the drive circuits 6a to 6d in accordance with the charge-on signal *CHON, and when a certain amount of charge is reached, issues a charge OK signal *CHOK to the signal generation circuit 5b, and triggers the trigger signal TRG. In response to this, the trigger electrode 21 of the flash lamp 2o is triggered to emit light.

FIG. 4 is a time chart diagram of one embodiment of the present invention, and FIG. 5 is an explanatory diagram of the operation of one embodiment of the present invention.

When the paper detection signal PS is output from the fixing timing sensor 4b to the main control unit (hereinafter referred to as MPU) 5a, the MP
After the lapse of time, tJ5a outputs the fixing instruction signal X0NOK to the signal generating circuit 5b.

Then, after a period of time (t+α) has elapsed, the MPU 5a outputs the charge-on instruction signal CHONM to the signal generation circuit 5b.

In this example, it is assumed that one sheet of cut paper CP is fixed by emitting light twice as shown in FIG.

When the charge-on instruction signal CHONM is applied while the fixing instruction signal X0NOK is applied, the signal generation circuit 5b outputs an inverted signal of the charge-on instruction signal CHONM to the power supply 6 as a charge-on signal *CHON.

The power supply 6 changes the drive direction ii! in response to the charge-on signal *CHON. Charge the capacitors C of 36a to 6d.

When the power supply 6 charges the capacitor C to a predetermined amount,
The charge OK signal *CHOK is returned to the signal generation circuit 5b.

The signal generation circuit 5b outputs a trigger signal TRG to the power supply 6 in synchronization with the off of the charge-on instruction CHONM of MP[J5a, and the power supply 6 outputs the trigger signal TRG to the flash lamp 2 via the trigger transformer Tr.
0 trigger electrode 21 is triggered to cause the flash lamp 20 to emit light.

Here, the high level period of the charge-on instruction signal CHONM (i.e., the low level period of the charge-on signal *CHON) TI is the necessary and sufficient time for the capacitor C to accumulate enough charge to cause the flash lamp 20 to emit light. It is necessary to take

Then, a trigger signal TR is generated from the leading edge of the paper detection signal PS.
The time T until the output of G (that is, the charge-on instruction signal CHONM is turned off) is determined by assuming that the distance from the sensor 4b to the exit of the flash fixing unit 2 is l, and the transport speed of the cut paper CP is x as shown in FIG. If p, it is necessary to set T≦17vp.

Since this time T is T=t+α+T1, the generation timing 1, 1+α of the fixing instruction signal X0NOK and charge-on instruction signal CHONM is determined according to the transport speed of the cut paper CP, and is the waiting time for the cut paper CP to arrive. .

In this way, in this example, -& cut paper CP
On the other hand, a flash is emitted in each half area and fixed.

(b) Description of other embodiments In the embodiments described above, the image forming section was constituted by an electrophotographic printing section, but other well-known powder image forming means may be used, and the detection means may also be connected to the fixing section and the image forming section. Although the sensor 4b provided between the forming part and the forming part is used, a write timing sensor 4a may also be used.
In short, it suffices as long as it is on the upstream side of the fixing section.

Further, fixing is performed by emitting flash light twice on one sheet of cut paper, but it can also be done by emitting flash light once or three or more times depending on the size of the flash emitting area and the length of the cut paper.

Further, the four flash lamps may be lit simultaneously or may be lit sequentially, and the number of flash lamps is not necessarily limited to four due to the relationship between the paper conveyance speed and the fixing area.

Although the present invention has been described above using examples, the present invention can be modified in various ways according to the gist of the present invention, and these are not excluded from the present invention.

〔Effect of the invention〕

As explained above, according to the present invention, the flash fixing operation of the flash fixing section is controlled to H' based on the output of the detection means.
tB allows flash fixing when the cut media actually reaches the flash fixing unit, which has the effect of preventing unnecessary flash emissions, preventing wasted energy and unnecessary temperature rises, and reducing the lifespan of each part. It can also be prevented.

[Brief explanation of drawings]

Fig. 1 is a principle diagram of the present invention, Fig. 2 is a configuration diagram of an embodiment of the invention, Fig. 3 is a block diagram of an embodiment of the invention, Fig. 4 is a time chart diagram of an embodiment of the invention, FIG. 5 is an explanatory diagram of the operation of one embodiment of the present invention, and FIG. 6 is an explanatory diagram of the prior art. In the figure, 1-image forming section, 2-flash fixing section, 4-detection means, 5-control section.

Claims (1)

[Claims] An image forming unit (1) that forms a powder image on a cut medium (CP).
), and a flash fixing unit (2) that flash-fixes a powder image on the cut medium (CP) being conveyed, the cut is placed on the upstream side of the conveyance direction of the flash fixing unit (2). A detection means (4) for detecting the medium (CP), and a control section (5) for controlling the flash fixing of the flash fixing section (2) based on the detection output of the detection means (4). A flash fixing control system featuring: