JPS6097334A - Control method of original scanning means - Google Patents

Abstract

PURPOSE:To prevent disturbance of copied pictures due to changeover between forward movement and backward movement of a clutch by moving backward an original platen after a recording paper passes a transfer part completely. CONSTITUTION:The timing of backward movement of an original platen 1 is shifted to move backward the original platen 1 after the recording paper passes the transfer part completely. That is, the recording paper passes completely the transfer part with pulse number 420, and power is supplied to an original platen clutch with pulse number 425. Consequently, changeover between forward movement and backward movement of the original platen 1 has no influence upon the transfer process of the recording paper.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a method for controlling document scanning means of a copying machine.

[Prior art]

Conventionally, the document scanning means of a copying machine temporarily stops its operation after completing document scanning, switches the forward and backward clutches of the drive mechanism of the document scanning means, and after being stopped for a certain period of time, returns to the document scanning start position. It is configured to operate in a return manner.

In such conventional control systems for document scanning means, especially when the drive source is shared with the drive source of the photoconductor and the drive source of the recording paper conveyance system, the document image is transferred from the photoconductor to the recording paper. If the document scanning means is switched between forward and backward at this point, a sudden change in the load on the drive source may cause fluctuations in the rotation of the drive source, and vibrations caused by impact may cause disturbances in the transfer pattern. There were drawbacks.

[Purpose of the invention]

The object of the present invention-1 is to provide a method for controlling a document scanning means that prevents disturbances in the copy program stage caused by the switching and returning operation to the scanning start position after the document scanning means finishes scanning the document.

[Summary of the invention]

According to the present invention, the timing for starting the return operation to the scanning start position after the document scanning means is temporarily stopped at the end of scanning the document is set after the transfer of the document image on the photoreceptor to the recording paper is completed. This prevents disturbances in the copied image caused by the switching and returning operation of the document scanning means to the scanning start position.

The time when the transfer to the recording paper is completed is when the count value of a series of pulses emitted from the start of the copying operation reaches a predetermined value required in a predetermined transfer completion building, or when the count value of a series of pulses emitted from the start of the copying operation reaches a predetermined value, or when the count value is set at the downstream side of the transfer means. This method uses the time point at which the trailing edge of the recording paper is detected by the recording paper detection sensor.

[Embodiments of the invention]

Examples of the present invention will be described below.

Figure 1 (5) is a schematic diagram of a configuration example of a copying machine to which the present invention is applied, mainly showing the original scanning system and recording paper feeding system. FIG. 1(B) shows the state at the start of scanning, and FIG. It is configured to scan the document surface.The scanning start position of the document table 1 is as follows.
It is detected by a magnet 2 provided on the document table 1 and a corresponding reed switch 3 attached to the main body of the copying machine.

The original image is irradiated by an exposure lamp 4 and is focused on a photoreceptor 6 through a SELFOC lens 5 to form a latent image. On the other hand, in the recording paper feeding system, recording paper is fed from a paper cassette 7 by a paper feed roller 8, synchronized with the latent image on the photoreceptor 6 by a registration roller 9, and fed to a transfer section. . In the transfer section, the recording paper is charged by a transfer corona charger IO.
The developed and visualized original image is transferred, passed through a conveyance bell I-11, fixed by a fixing device 12, and discharged onto a paper discharge tray J3. In addition,
Reference numeral 14 denotes a post-transfer recording paper detection sensor disposed between the transfer corona charger 10 and the conveyor belt 11.

FIG. 2 is a time chart showing the operation mode of each part when a copying machine having such a configuration is operated using a conventional document scanning means control method. The number of pulses on the chart is
It shows the total number of pulses generated in synchronization with the rotation of the photoreceptor 6 from the start of copying, and normally one pulse corresponds to the moving time of one set of recording paper. In the conventional control system, first, when a print key (not shown) is pressed, the copy operation is started, and the main drive motor (
(not shown) starts driving. At this point, the document table l is in the state shown in FIG. 1 (5).

At the same time as copying starts, exposure lamp 4 is turned on.
A corona charger (not shown) is activated, and the registration rollers 9 are rotated via a clutch (not shown). Simultaneously with these operations, a document table advance clutch (not shown) is energized and driven, and the document table 1 moves in the document scanning direction.

The paper feed roller 8 is fed via a clutch (not shown).
It rotates with a slight delay after the start of copying, that is, between 15 and 70 /C pulses, and feeds recording paper from the paper feed cassette 7. On the other hand, registration roller 9 started rotating at the same time as copying started.
The leading edge of the recording paper is kept on standby by opening and stopping pulses 35 to 60, synchronized with the latent image formed on the photoreceptor 6,
One counter rotation is started again with the number of pulses of 60, and the recording paper is fed into the transfer section.

At the timing of 350 pulses, the document table 1 is moved as shown in FIG.
The state shown in 13) is reached, the scanning is completed, and the exposure/pull step 4 is completed.
, the corona charger, and the document table advance clutch are turned off.

Next, at the timing of the number of pulses 380, a document table backing clutch (not shown) is energized and driven, and the document table 1 is moved in the opposite direction to the scanning direction. Furthermore, as mentioned above,
When switching the document platen clutch for forward or backward, please allow for the response time of the clutch, the inertia of the document platen 1, etc.
The timing of energization of the document platen retreating crankshaft is shifted by 30 pulses. Since the document table 1 is configured to move at a speed of 1 when moving backward and twice as fast as when moving forward by changing the gear ratio, at the timing of the number of pulses 555, the document table 1 moves to its scanning start position i+gt. (the state shown in Figure 1), the scan start position detection reed switch 3 is closed by the magnet 2 of the document table IJ2, and the detection signal causes the scan start position detection reed switch 3 to close.
Via the control section, the document table back clutch is turned on 2, and the document table j is stopped. On the other hand, the recording paper is transferred at a rate of <1X, and then is discharged to the paper discharge tray 13 via the fixing roller 12, at which point the copying operation ends, and the number of pulses at this time is about 600.

During the above series of copying operations, the number of pulses during the period when the recording paper passes through the transfer section is the second pulse number for A4 size recording paper.
As shown in the figure, they range from 120 to 420.

In the conventional control system, as can be seen from this figure, the document table 1 is switched between forward and backward during this period, and the torque fluctuations and vibrations at this time have an adverse effect on the transfer operation to the recording paper. It gives

FIG. 3 is a time chart showing the operation mode of each part when controlling the document scanning means by the control method according to the present invention. The present invention focuses on the drawbacks of the conventional control method described above, and shifts the timing of the retreat of the document table 1 so that the document table 1 is moved back after the recording paper has completed passing through the transfer section.

That is, as shown in FIG. 3, the recording paper has a pulse number of 42.
0, it completely passes through the transfer unit, but the document platen backward clutch is energized at a pulse number of 425 after the completion of the passage. By controlling the drive of document table L in this way, document table ■ starts to move backward after the recording paper has been completely transferred. It is possible to avoid the influence of

FIG. 4 shows a block diagram of a control section used to control the copying machine operation by applying such a control method. 15
is the control board, 0PU16, OM with built-in program.
17. Equipped with 1 tA and MI8 for data storage, it is connected to the human power sensor group 21 and each output load 22 through the input interface 19 and the output interface, and is connected to the input signal from the input frame group 2. It is configured to control each output load 22. Note that 23 is a pass line. The sensors, exposure lamps, clutches, etc. shown in FIGS. 2 and 3 are part of the input sensor group 21 or the output load 22.

FIG. 5 shows a flowchart 1 of a program for executing energization control of the document table reverse clutch in the control method according to the present invention shown in FIG. This routine is executed every time the number of pulses is counted up from the start of copying, and when the number of pulses reaches 425, a control signal is output to energize the document table back clutch.

FIG. 6 is a time chart showing the operation mode of each part of the copying machine under control of another embodiment of the control method of the present invention. In this embodiment, the post-transfer recording paper detection sensor 14 shown in FIG. This controls the clutch to be energized.

In the configuration example shown in FIG.
In the case of a size of recording paper, the detection sensor 14 detects the recording paper at a pulse number of about 130 to about 430. Note that this number of pulses is an approximate number, so in the drawing,
It is shown in parentheses.

In this embodiment, as in the @<1 embodiment, the operation of the document table can be controlled using the control board including the 0 1) U shown in FIG. 4. A flowchart of a program for executing seven steps of detecting the trailing edge of the recording paper by the recording paper detection sensor 14 after transfer and energizing the document platen backward clutch in this embodiment is shown. This routine is executed at regular intervals and constantly detects the state of the recording paper. While the paper detection sensor 14 is detecting recording paper, the paper detection flag provided on the RAM 18 is set to "
When the paper detection sensor 14 no longer detects recording paper and the paper detection flag is "1", set it to "0" when it is not detecting the recording paper. is detected, and a control signal is output to energize the document platen retraction clutch.With this control,
After the transfer to the recording paper is completely completed, the document table can be configured to return to the scanning start position.

〔Effect of the invention〕

According to the present invention, the document scanning means is temporarily stopped at the end of scanning the document, and the timing for starting the return operation to the scanning start position is adjusted to
Since the transfer is performed after the transfer of the original image on the photoconductor 2 to the recording paper is completed, there is no disturbance in the copied image due to switching of the forward and backward clutches when the original scanning means returns to the scanning start position. can be prevented.

In particular, when the driving force for the document scanning means is obtained from the same drive source as the drive source for conveying the photoreceptor or document, rotation fluctuations occur due to torque fluctuations in the drive source due to switching of the forward and backward clutches, resulting in image disturbances. is likely to occur, so the effect of applying the control method according to the present invention is significant.

[Brief explanation of drawings]

FIG. 1 (5), (Bl is a schematic diagram of a configuration example of a copying machine to which the present invention is applied, and FIG. 2 is a time diagram showing the operation of each part of the copying machine controlled by the conventional manuscript table control method. 3 is a time chart showing the operation of each part of the copying machine controlled by the document scanning means control method of the present invention, and FIG. 4 is a block diagram of the control section used in the document scanning means control method of the present invention. , FIG. 5 is a flowchart of a part of the program for executing the control method according to the present invention, and FIG. 6 is a time chart showing the operation of each part of the copying machine controlled according to another embodiment of the present invention. Fig. 7 is a flowchart of a part of a program for executing another embodiment of the present invention. 1 is a paper roller, 9 is a register roller, 10 is a transfer corona charger, 12 is a fixing roller, 1
4 is a recording paper detection sensor after transfer, 15 is a control board,
J9 is the input interface, addition is the output interface,
Reference numeral 21 indicates an input sensor group, and 22 indicates an upper load. 5th Seki

Claims (3)

[Claims] (1) Copying comprising an original scanning means, a photoreceptor that holds the original image scanned by the original scanning means, and a transfer means that transfers the original image visualized by development on the photoreceptor onto recording paper. In the apparatus, the document scanning means is temporarily stopped at the end of document scanning, and the timing for starting the return operation to the scanning start position is set after the completion of transfer of the visualized document image on the photoreceptor to the recording paper. A method for controlling a document scanning means. (2) The timing of the return operation of the document scanning means to the scanning start position is such that the count value of a series of pulses emitted from the start of the copying operation reaches a predetermined value corresponding to the completion of transfer to the recording paper. 2. A document scanning means control method according to claim 1, wherein said document scanning means is controlled at a point in time when said document scanning means is reached. (3) A patent claim characterized in that the timing for starting the return operation of the document scanning means to the scanning start position is set at the time when a trailing edge 1 of the recording paper is detected by a recording paper detection sensor provided on the downstream side of the transfer means. A method for controlling a document scanning means according to item 1.