JPS6093472A - Copying machine - Google Patents

Abstract

PURPOSE:To eject surely forms remaining in a carrying path by providing a control means which operates a separatig means for a prescribed time from the copy start. CONSTITUTION:When a print key 21 is turned on, the logical level of an output signal S3 of an OR circuit 34 becomes high, and as the result, a separating pawl solenoid 35 is turned on to bring a separating pawl 12 into contact with a photosensitive drum 1, and the separating pawl 12 is controlled by a device control part 20 so that it is brought into contact with the photosensitive drum 1 for a prescribed time and is operated at a normal timing thereafter. Even if a form PP is already sent and is stopped in any position of a guide plate 8 before the print key 21 is turned on, the form PP is separated from the photosensitive drum 1 by the separating pawl 12 when the front enf of the form PP is moved to the separating pawl 12, and the form PP is ejected to an eject tray 15 by a carrying belt 13.

Description

[Detailed description of the invention] [Technical field] The present invention relates to a copying machine.

[Prior Art] Normally, in a copying machine, paper gets jammed somewhere along its conveyance path.
If a jam occurs, there is a risk of damaging each device. Therefore, a paper detector is provided at an appropriate location on the conveyance path, such as a registration section for correctly positioning the paper on the photoreceptor.
It monitors whether the paper is passing through the conveyance path at the appropriate timing and detects a jam.

Conventionally, such jam detection has been performed based on the timing when the paper feeder begins to feed the paper from the paper cassette.
(Since this was done as 0, the following problems occurred.

That is, for example, when a jam occurs while making multiple copies, even if the operator removes the paper that caused the jam, the subsequent paper has just been fed out from the paper presser 1-. If the paper is not discovered by the operator, the paper may be left in a state where it has advanced to a position where it is not detected by the paper detector in the middle of the conveyance path.

In this case, when the operator resumes copying after completing the post-jam processing, if the paper remaining in the conveyance path is not detected as a jam, the paper will stick tightly to the photoreceptor and pass through the transfer and separation sections. , there is a risk that the particles may enter the cleaning section that removes residual toner on the photoreceptor and damage the cleaning section.

[Objective] The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and it is an object of the present invention to provide a copying machine that can reliably remove paper remaining in the conveyance path.

[Configuration] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows an outline of a copying machine DM according to an embodiment of the present invention.

In the figure, reference numeral 1 denotes a photoreceptor drum that is rotationally driven in the direction of the arrow, 2 a stationary charger that uniformly charges the surface of the photoreceptor drum 1, and 3 an original (as shown) placed on the charged photoreceptor drum 1. It is an optical system that exposes an image, and the photosensitive drum 1
An electrostatic latent image is formed on the surface of the exposed image. This electrostatic latent image is developed with toner by a developing device 4.

5 is a paper feed roller that feeds the paper PP from the paper cassette 6;
7 is a pair of transport rollers that are constantly rotating in the direction of the arrow and transports the paper [)P sent out by the paper feed roller 5; 8 is a pair of paper pp
This is a guide board to guide you.

9 is a pair of registration rollers for aligning the leading edge of the toner image on the photosensitive drum I with the leading edge of the paper PP; 10 is a transfer charger for transferring the toner image on the photosensitive drum 1 onto the paper PP; 11 and Reference numeral 12 denotes a separation charger and a separation claw for separating the paper PP from the photoreceptor drum l, and the separation claw 12 is normally retracted to the position shown by the broken line so as not to damage the surface of the photoreceptor drum 1. I have to.

13 is a vacuum type conveyor belt that attracts and conveys the separated paper PP; 14 is a pair of fixing rollers that heats and presses the paper PP to fix the toner image; 15 is a paper PP
This is the discharge tray from which the paper is discharged.

Reference numerals 16 and 17 denote a pre-cleaning static elimination charger and a cleaning unit that clean the surface of the photoreceptor drum 1, and 18 a static elimination charger that eliminates static electricity from the surface of the photoreceptor tram l. Further, 19 is a paper detector for detecting that the paper PP is located at the position of the registration roller pair 9.

Each of the above-described elements of the copying machine DH is controlled in synchronization so as to properly execute a well-known copying process.

Now, in the present invention, the paper PP remaining in the conveyance path is discharged to the discharge tray 15 by operating the separation claw I2 for a certain period of time after the start of copying.

A means for realizing such control is shown in FIG.

In the figure, 20 is a main body control unit that controls each element of the copy*DM, and in the illustrated circuit, among the control signals output by this main body control unit 20, the clutch of the paper feed roller 5 (when shown) is turned on and off. A paper feed clutch control signal FC1 is used to turn on and off the clutch of the pair of registration rollers 9 (as shown).

Further, 21 is a print key provided on an operation panel (not shown), and a print start signal PS of this print key 21 is applied to the main body control section 20.

Now, suppose that the operator turns on the print key 21 to make a copy, the printer 1-start signal PS (see FIG. 3(a)) is output, the flip-flops 30 and 31 are reset, and these outputs are The logic level of signals 51 and 52 (see Figures 3(d) and (e)) becomes rlJ, and the signal S2 (see Figure 3(f)
(see) logical level becomes obsolete.

As a result, the AND circuits 32 and 33 are rendered inoperable, and the output signal Ss of the OR circuit 34 (FIG. 3 (j)
) becomes old, and as a result, the separation claw solenoid 35 is turned on and the separation claw 12 comes into contact with the photosensitive drum 1. At the same time, the main body control unit 2o starts copying control, and first the registration clutch is turned on. The control signal RC (see FIG. 3(c)) is set to the old logic level for a predetermined time T1, and the registration roller pair 9 is preliminarily operated to cancel the deflection, etc., occurring in the registration roller pair 9.

Further, the main body control unit 2o changes the paper feed clutch control signal FC (see FIG. 3(b)) to a logic level rl at a predetermined timing.
1J, held for a time T2, and operates the paper feed roller 5 to feed the first sheet PP from the paper cassette 6.

The rising edge of this paper feed clutch control signal FC is detected by the differentiating circuit 36, which sets the flip-flop 30 so that the output signal s1 becomes "old" and the AND circuit 32 becomes operational. Ru.

Here, if the paper PP has already been sent out and stopped at any position on the guide plate 8 before the operator turns on the print key 21, the paper PP is transported by the transport roller pair 7, It is further conveyed by a pair of registration rollers 9.

When the leading edge of the paper PP has moved to the separation claw 12, the separation claw 12 is in contact with the photosensitive drum 1 as described above. Therefore, this paper PP is separated from the photosensitive drum 1 by the separation claw 12 and is ejected onto the ejection tray 15 by the conveyor belt 13.

At this time, this paper PP is detected by the paper detector 19, and its detection signal DP (see FIG. 3(g)) rises to the logic level "old," but the logic level of the signal S2 is r.
Since it is LJ, the output of AND circuit 33 does not change.

Monomulti 40 is not triggered.

On the other hand, when the resist clutch control signal RC rises to the logic level "old" at a predetermined timing after the preliminary operation, this rise is detected by the differentiating circuit 37, and the detection signal is applied to the flip-flop 31 via the AND circuit 33. This causes the logic level of the signal S2 to rise to "old" and the logic level of the signal n to fall to rLJ.

As a result, the AND circuit 33 becomes operational and the logic level of the output signal s3 of the OR circuit 34 becomes rlJ.
Therefore, the separation claw solenoid 35 is turned off and the separation claw 12 is separated from the photosensitive drum 1.

Then, the paper PP sent out by the paper feed roller 5 after this
is detected by the paper detector 19, and the detection signal DP rises to the logic level "old", the output of the AND circuit 33 rises to the logic level rHJ, the monomulti 40 is triggered, and the signal P+(th 3(h)) is output.Furthermore, the monomulti 41 is triggered by the fall of this signal P1, and a signal P2 (see FIG. 3(i)) with a pulse width τ2 is output.

This signal P2 causes the logic level of the output signal s3 of the OR circuit 34 to rise to rHJ, thereby turning on the separation claw solenoid 35 and causing the separation claw 12 to come into contact with the photosensitive drum l.

Here, the pulse width of the signal P1 is set to be slightly smaller than the time required for the paper PP to move from the registration roller pair 9 to the separation claw 12, and the pulse width of the signal P2 is set to τ.
2 is set to such an extent that the separating claw 12 can separate the leading end of the paper pp.

Therefore, after the separation claw 12 comes into contact with the photoreceptor drum 1, the paper PP is conveyed to the separation section, whereby the paper PP is separated from the photoreceptor drum l by the separation claw 12.

After the separation claw 12 is kept in contact with the photosensitive drum 1 in this manner until a predetermined period of time has elapsed from immediately after the start of copying.

The separation claw 12 is operated at normal timing.

In the embodiment described above, only the separation claw 12 is operated until a predetermined period of time has elapsed from immediately after the start of copying, but the separation charger 11 may also be operated.

By the way, if a paper collating device is connected to the copying machine DM, the paper PP ejected before the first regular sheet is ejected to the output tray without being sent to the paper collating device, and the paper PP is ejected at the timing before the first regular sheet. It is only necessary to send only the paper to the paper collating device. To do this, for example, a means for switching the paper conveyance path so that the paper is conveyed to the ejection tray instead of the paper collation device from the start of copying until the timing when the first regular sheet of paper is sent to the paper collation device. All you have to do is set it up.

[Effects] As described above, according to the present invention, there is an advantage that paper remaining on the conveyance path can be reliably discharged and damage to the cleaning section can be prevented.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram showing an embodiment of the present invention, Fig. 2 is a block diagram showing an example of a control system, and Figs. 3 (a) to (j) are waveform diagrams showing the operation of each part of the control system. It is. 9... Registration roller, 11... Separate charger. 12...Separation claw, 19...Paper detector, 20...Main body control unit, 21...Print key, 30.31...
Flip-flop, 32.33...AND circuit, 3
4...OR circuit. 35... Separation claw solenoid, 36.37... Differential circuit, 1) 0, 41... Mono multi.

Claims (1)

[Claims] A copying machine that separates paper after transfer from a photoreceptor by a separating means is provided with a control means that operates the separating means for a predetermined period of time after the start of copying, and forcibly discharges residual paper remaining on a conveyance path. Characteristic copying machine.