JPS5927496B2 - Charging method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a recording medium whose moving speed is irregularly changed;
For example, the present invention relates to a charging method that is effective when applied to a facsimile machine that uses an electrostatic recording medium that is charged with an electric charge to form an electrostatic latent image on the charged portion.

The recording medium of devices such as facsimile machines, where the moving speed of the recording medium changes irregularly, is charged by a corona charger that applies a high DC voltage, such as that used in electronic copying machines. If this is done, the charging time differs depending on the moving speed, such that portions of the recording medium where the moving speed is fast are charged low, and portions where the recording medium is moving slowly are charged highly, resulting in uneven charging.

This charge unevenness has a significant effect on the quality of the obtained image. In a facsimile machine, a step motor is used as a driving source, and the moving speed of the recording medium is changed depending on the number of applied pulse voltages.

That is, one pulse rotates the rotating shaft of the step motor by a predetermined angle, and the moving speed of the recording medium is determined by how many pulse voltages are applied per time. For example, the angle of the motor shaft is rotated by 1 degree per pulse, and the recording medium is moved by 1/16 mm via the pulley. The present invention uses a pulse motor (step motor) as a drive source for a recording medium, and is capable of uniformly charging the recording medium in an apparatus having means for applying an electric charge to the recording medium for the purpose of charging or eliminating static electricity. Another object of the present invention is to provide a charging method that improves charging unevenness caused by a difference in moving speed of a recording medium by intermittent output of the charging means based on a pulse input to a pulse motor. It is.

FIG. 1 schematically shows the structure of a transfer type facsimile machine, which is an example of a device in which a recording medium is moved with irregular speed changes by a step motor, and has charging means.

In the figure, 1 is an electrostatic recording medium, which has a head 2.
gives an electrostatic latent image of negative polarity. Toner positively charged by the developing device 3 is attached to this electrostatic latent image, and the image is visualized. The developed electrostatic recording medium 1 is transferred to a transfer paper 5 by a corona transfer device 4, and the toner on the transfer paper is fixed by a fixing device 6 and discharged outside the machine. On the other hand, since toner remaining during transfer and an electrostatic latent image remain on the electrostatic recording medium 1 after transfer, the entire area of the electrostatic recording medium is brought to a potential of the electrostatic latent image by the cleaning charger 7. After being charged to the same potential, the fur brush 8 removes the toner, and the static eliminator 9 removes the latent image and
One step is completed by neutralizing the negative charge caused by the cleaning charge.

10 and 11 are sprocket wheels for moving the electrostatic recording medium 1, and 12 is a pulse motor (step motor) for driving the sprocket wheel 10, the rotational speed of which can be adjusted freely depending on the number of pulse voltages input. It can change.

A sponge roller 13 serves to stabilize the contact between the head 2 and the electrostatic recording medium 1 when the head 2 performs recording.

Next, an experiment conducted using the apparatus shown in FIG. 1 revealed the charging state when charging using conventional direct current and when charging using intermittent high voltage of the present invention, that is, pulsed high voltage. Compare.

Platinum was placed on a polyester film with a thickness of 100 μm at 1×10 7 Ω/hole (two copper electrodes weighing 1 kg were placed 35 mm apart on a 35 mm wide sample, and a direct current of 10 Ω was applied between the electrodes).
100 parts of unsaturated polyester and 25 parts of calcium carbonate with a particle size of 8 to 15 μm were mixed with monochlorobenzene on a conductive treated film [High Beam T manufactured by Toray Industries] which had been deposited to a resistance value of 0 V (value measured by applying a voltage of 0 V). 5-6 μm of paint made by dissolving and dispersing in a mixed solvent of dichloroethane
A recording layer was formed by coating to a film thickness of m, and an electrostatic recording medium was prototyped.

The electrostatic recording medium thus produced was loaded into the transfer type facsimile machine shown in Fig. 1, and a DC high voltage of -6,0 KV was applied to the corona transfer device, and the recording medium was moved at a speed of about 15 mm in the first half. /second, the second half is about 67mm/second2
Adjust so that the stages change automatically, recording, developing, transferring,
Each process of charging for cleaning, cleaning, and neutralization was performed continuously, and the charging potential was measured using a corona transfer device as a representative charging device. Actually, the potential charged on the electrostatic recording medium through the transfer paper during transfer was measured, and the relationship between the charged potential and the moving speed of the recording medium was investigated. Table 1 shows the results. The measurement points in the table are predetermined locations spaced from the center of the electrostatic recording medium at intervals of 5c7rL parallel to the direction of movement of the electrostatic recording medium.

Measurements at measurement points 1, 2, 3, and 4 show that the moving speed of the recording medium when passing through the corona transfer device is 15 m7! In the case of L/sec, the measurement at measurement points 5, 6, and 7 is 67m77! /second. As is clear from Table 1, in the conventional charging method, there is a very large difference in the amount of charge depending on the moving speed of the recording medium.

A similar thing occurs with charging devices such as cleaning chargers and static eliminators. Furthermore, this occurs irregularly due to the location of each charging device, and when one process is completed, uneven charge removal due to insufficient charge removal or excessive charge removal occurs, which significantly deteriorates the obtained image. Next, the charging method of the present invention and the effects obtained will be explained using examples. [Example 1] Using the same electrostatic recording medium and transfer type facsimile device as in the case of using DC high voltage in the conventional example described above, a pulsed negative high voltage of 6.0 KV according to the present invention was applied to the corona transfer device.
was applied.

The pulsed high voltage used in this example is obtained by the configuration shown in FIG. That is, the output pulses of the step pulse generator 14 having a variable number of pulses are divided into two systems, one of which is applied to the pulse motor 12 through the pulse motor driver 15. On the other hand, the pulse frequency dividing circuit 16 divides the frequency into 1/32 by taking into account the rise and fall of the pulsed high voltage.
A monostable multivibrator 17 provides a constant amplitude application time. During this application time, the primary side of the transformer-type high-voltage power supply 19 is turned on and off by the AC relay 18, and a pulsed high voltage for charging is obtained from the high-voltage power supply 19.
By this process, uniform charging can be performed on a fixed area to the extent that no practical problem occurs, regardless of the moving speed of the recording medium. Table 2 shows the results obtained by applying the pulsed high voltage obtained by intermittent input voltage of the DC high voltage power supply shown in Fig. 2 to the corona transfer device and using the same measurement method as in Example 1. This shows the charging potential.

Compared to the results obtained by the conventional method using a DC high voltage power supply, the overall charging potential is lower and 16
mm/sec and 67m7! The difference in charging potential at the moving speed of the recording medium of L/sec is becoming smaller. In addition, the images obtained when pulsed high voltage was applied to the cleaning charger in the same manner showed dirt and grime due to insufficient static removal.
No decrease in concentration due to excessive charge removal was observed, and the result was very good. The image obtained when applying a DC minus 6.0 KV to the cleaning charger using the conventional method is as follows.
Ground stains occurred due to insufficient static electricity removal. [Example 2] FIG. 3 shows a further improvement of Example 1.

That is, a DC-DC power supply using a flypack transformer is used as the high-voltage power supply 19/, a capacitive load is removed, and responsiveness to application time is improved. Table 3 shows the results, and it can be seen that the charging unevenness caused by the moving speed of the recording medium has been eliminated. The image obtained in this case is
As in Example 1, when a DC voltage of -6.0 KV was applied to the cleaning charger using the conventional method, soiling occurred due to uneven charge removal. When a voltage of 6.0 KV) was applied to the cleaning charger, very good images were obtained. In this way, in the charging means of a device in which the moving speed of the recording medium changes, synchronizing the moving speed and the voltage applied to the charging means is equivalent to the recording medium moving at a constant speed, and from this, It becomes possible to eliminate charge unevenness.

In addition, in the above-mentioned embodiment of the present invention 5, a case was described in which a corona transfer device was used as a charging device, but as a charging means, a method of contacting a conductive roller, a metal piece, etc. in addition to corona can be used. But it's okay. Further, in the transfer type facsimile device shown in FIG. 1, if all the high voltages applied to the cleaning charger and static eliminator other than the corona transfer device are pulsed according to the present invention, further effects can be obtained. can be easily inferred. Figure 4 A, b, c,
d and e show the relationship between the input pulse of the pulse motor, the frequency dividing circuit output, and the monostable multivibrator output, and the output waveform of the high-voltage power supply that is finally applied to the charger for Examples 1 and 2. It is something that

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of a transfer type facsimile device for explaining an application example of the present invention, and FIGS. 2 and 3 are main part block diagrams for explaining each embodiment of the present invention, respectively.
4A, b, c, d, and e are signal waveform diagrams of various parts in FIGS. 2 and 3. 1... Electrostatic recording medium, 4... Corona transfer device, 7... Cleaning charger, 9...
... Static eliminator, 12 ... Pulse motor, 14
...Step pulse generation circuit, 16...
・Pulse frequency divider circuit, 17... Monostable multivibrator, 18... AC relay, 19, 15...
...High voltage power supply.

Claims (1)

[Claims] 1 A pulse motor that moves the recording medium irregularly,
A charging method in an apparatus comprising a charging means for applying an electric charge to the recording medium, wherein the charging output of the charging means is intermittent in response to pulses from a pulse supply source that drives the pulse motor. A charging method characterized by: