JPH0693074B2 - Optical system scanning controller for electrophotographic copying machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning drive of an optical system in a dry electrophotographic copying machine.

Conventional technology Scanning of the optical system consists of skian traveling in which the light emitted from the exposure lamp scans the surface of the original on the platen glass on the original placing table and return traveling to return, and normal return traveling is faster than skian traveling. Yes, after the skian ends, it returns at high speed to prepare for the next skian start timing.

Since the scanning start timing requires alignment between the leading edge of the original and the leading edge of the copy sheet, a certain sheet feeding state is set to that point regardless of the size of the sheet.

Therefore, if the paper size is larger than the scanning distance of the optical system, the paper is still in the specified position at the end of the return, so the return end state remains until the next paper is fed and scanning starts. You will have to wait. At that time, in the continuous copying state, the exposure lamp continues to be in a lighting state, so that heat generation at the standby position becomes a problem.

Now, the conventional scanning of the optical system will be described with reference to FIGS.

FIG. 2 is a schematic explanatory view of the main part of the copying machine. In FIG.
Reference numeral 01 is a platen glass serving as a document placing table, and the document 02 is placed with the front side facing down. Below the platen glass 01, an exposure lamp 03 such as a halogen lamp which is a light source of the scanning optical system.
And a drum-shaped photoreceptor in which light is imaged through a plurality of mirrors 04 that change the direction of light emitted from the exposure lamp 03.
05 is installed.

A charge corotron 06, a developing device 07, a transfer corotron 08, etc. are arranged around the drum-shaped photoconductor 05, and the photoconductor surface uniformly charged by the charge corotron 06 is passed through the optical system. An electrostatic latent image is formed by the reaching light, the toner is attached by the developing device 07, and the toner image is transferred to the sheet by the transfer corotron 08.

An image is transferred to the transferred paper by a fixing device (not shown), and a series of copying processes is completed.

Reference numeral 09 is a paper tray for stocking paper, and the paper is fed one by one from the topmost one by driving the feed roll 010.

A photo sensor 011 for detecting the passage position of the paper before the transfer is installed in the paper conveyance path from the paper tray 09 to the position of the transfer corotron 08 together with a conveyance device (not shown).

The timing charts showing the driving states of the scanning of the optical system, the exposure lamp and the photo sensor are shown in FIGS. 3 to 5.

In the same timing chart, the upper diagram shows the position of the optical system, the middle signal shows the lighting state of the exposure lamp, and the high level is the lighting state, and the low level is the extinguishing state. The lower signal shows the detection state of the paper by the photo sensor 011.When the signal is at the high level, it indicates that the paper is being detected.
When it is at the low level, the paper is not detected.

The timing charts shown in FIGS. 3 to 5 show the case where three copies are continuously performed.

FIG. 3 is a timing chart when the copy paper is shorter than the scanning distance of the optical system, and such driving is normally performed.

That is, when copying is started, the exposure lamp is first turned on (at the time when the signal rises), and then the feed roll 010.
Is driven and the paper is fed, and the photo sensor 011 detects the paper (at the time of rising of the signal), and at the same time, the optical system starts skimming.

When the sheet passes through the photo sensor 011 (at the time when the signal falls), the ski run is switched to the return run.

When the second sheet is fed and detected by the photo sensor 011 the scanning is started again.

As shown in FIG. 3, the scanning of the optical system can be shifted to the next scanning without waiting at the return end position.

This is also the case when the paper size becomes smaller.

However, when the paper size is longer than the scanning distance of the optical system, the optical system does not wait for the paper to pass through the photo sensor 011 and changes to return running at the scan end position at the scanning distance limit as shown in FIG. Since the paper has not passed through the photo sensor 011 even after the traveling is ended, the printer waits at the return end position.

Photo sensor 011 after the optical system reaches the return end position
Is the waiting time (between XY in FIG. 4) until the next sheet is detected.

During continuous copying, the exposure lamp remains lit during this waiting time, so that heat is concentrated on a part of the platen glass by the halogen lamp or the like, which causes a change in shape due to high heat and causes a problem.

Therefore, if the paper is longer than the scanning distance, it is possible to reduce the return speed to shorten the standby time.
If the return speed is kept constant in a slow state, when the paper is appropriately long, not only the scanning start time is delayed, but the entire copying time is lengthened as shown in FIG.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention relates to improvement of such a drawback, and the problem to be solved is to place the optical system at a certain position during continuous copying when the paper is longer than the scanning distance of the optical system. The point is not to wait for a long time and to delay the copying time.

Means and Actions for Solving Problems The means for solving such problems will be described with reference to FIG.

In a dry electrophotographic copying machine having a scanning optical system, A is a scanning position detecting means for detecting the scanning position of the optical system,
Reference numeral B is a paper feed position detection means for detecting the position of the fed paper at a predetermined position before transfer.

C is a scanning control means for controlling the scanning drive of the optical system,
Reference numeral D denotes a scanning drive unit that drives the optical system under the control of the scanning control unit.

E inputs information from the scanning position detecting means A and information from the paper feeding position detecting means B, appropriately determines the scanning return speed of the optical system based on the both information, and outputs the speed signal to the scanning control means. It is an information processing means for outputting to C.

Then, when the paper feed position detecting means B detects a sheet at the time when the optical system shifts to the return traveling, the information processing means E makes an initial constant speed return traveling, and the paper feeding detecting means B causes the sheet to travel. When no longer detected, the speed is changed to high-speed return traveling.

Therefore, the return travel of the optical system is performed in two steps, and the timing of returning to the return travel limit position is appropriately adjusted to the length of the paper by changing the time point of shifting from the constant speed to the high speed according to the length of the paper. It is possible to control the traveling without waiting for and to prevent the delay of the copying time.

Embodiment An embodiment according to the present invention shown in FIGS. 6 to 10 will be described below.

FIG. 6 is an explanatory view showing the position of a photo sensor for detecting the scanning position of the optical system arranged in the scanning path of the exposure lamp.

In the figure, 1 is a platen glass and 2 is an exposure lamp. The exposure lamp 2 travels in a rightward direction and travels in a leftward direction.

A scan sensor sensor 3 is installed at the scanning limit position at the right end of the platen glass 1, and a return end sensor 4 is installed at the return travel limit position at the left end.

In addition, a registration position sensor 5 for aligning the leading end of the fed sheet with the leading end of the document is arranged at a predetermined position near the return end sensor 4.

The above three sensors are reflection type photosensors, and the actuators integrally attached to the traveling optical system detect when the optical system reaches a predetermined position.

The other devices are the same as those shown and described in FIG. 2 in the section of the prior art.

FIG. 7 is a block diagram of the control system of this embodiment, and 10 is a CPU which is the center of information processing, and is driven while appropriately utilizing the RAM 12 according to the program written in the ROM 11.

As an input signal, the scan end sensor 3, the return end sensor 4, the registration position sensor 5
Signal from the photo sensor 01 mentioned in the prior art section.
There is a detection signal from the paper feed sensor 6 corresponding to 1, which is input to the CPU 10 via the input interface 13.

A drive control signal is output from the CPU 10 to the scanning motor 15, the feed roll driving motor 16 and the exposure lamp 2 of the optical system via the output interface 14.

In the above control system, scanning of the optical system is
When the paper is short, the conventional scanning control is performed, and when the paper is longer than the scanning distance, the following control is performed.

FIG. 8 is a timing chart when performing continuous copying of three sheets when the paper is longer than the scanning distance.

In the figure, the same signal as above indicates the lighting state of the exposure lamp, and the signal indicates the detection state of the paper by the sensor 6.

The signal is a drive signal of the feed roll drive motor 16 and is driven when it is at a high level.

When copying is started, the feed roll drive signal is set to a high level to drive the feed roll, the paper is fed, and then the exposure lamp is turned on and the paper feed sensor 6 detects the paper (the rising edge of the signal). ), The skiyan of the optical system is started.

Even if the scanning of the optical system reaches the skim travel limit position, if the paper feed sensor 6 still detects the paper (the signal is in the high level state), that is, if the paper is longer than the travel distance, the return travel is performed at this point. Switching is performed, and the return speed at that time is constant.

When the paper passes through the paper feed sensor 6 (the signal trailing time point P) and the optical system has not returned to the predetermined position, the return speed is increased at that time.

Here, the predetermined position is the registration position sensor 5
Is a position corresponding to the horizontal axis in the uppermost drawing showing the scanning position of the optical system in the timing chart at the position where is installed.

After the return speed is changed from low speed to high speed, the feed roll is driven at the time Q when the optical system passes the registration position (signal high level), the next paper is fed, and the optical system scans at the return travel limit position. Switch to running.

If the optical system has returned to the predetermined position at the point P when the signal falls during the low speed return traveling, the return speed is not changed. However, in this case, if the paper is extremely long compared to the scanning distance, the length of the paper used should be almost the maximum, and the optical system should move to the registration position sensor position almost at the same time as the signal falls. Design in advance so that it is back.

By designing in this way, it is possible to move to the next skimming run even for the maximum length of paper without making the optical system stand by at the return end position.

Therefore, if the paper has a length other than the maximum length, the return run is 2
By shifting the speed and changing the shifting time point from the low speed to the high speed according to the length of the paper, the timing at which the optical system returns to the return end position can be appropriately adjusted to the length of the paper as shown in FIG. Therefore, the copying time is not delayed without waiting the optical system.

The operation of the scanning drive control of the above optical system is shown in FIGS.
It is shown as a flow chart in the figure and will be described.

First, after setting the reduction ratio, the number of copies Z, etc. (step), when the start button is pressed (step), the feed roll is driven (step), paper is fed, and then the exposure lamp is turned on. (Step).

When the paper feed sensor 6 detects a paper by feeding the paper (step), the drive of the feed roll is stopped (step), and at the same time, skim running is started (step).

Next, the paper passes through the paper feed sensor and the paper feed sensor
When the F state is reached or the optical system reaches the limit of the scanning distance and the scan end sensor 3 turns ON, it is detected (step), and the paper feed sensor 6 turns OFF first. The value of the symbol K is set to 0 (step),
Stop skiing (step). This is the same as the conventional example when the paper is shorter than the scanning distance.

If the skimming end sensor 3 is turned on first, the value of the mode symbol K is set to 1 (step), and skimming is stopped (step). This is compared to the scanning distance
This is the case when the paper is long.

Then, the number of copies Z is decremented by 1 (step), and it is determined whether Z is 0 or not (step).

If Z = 0, the exposure lamp is turned off (step).

Here, it is judged whether or not the mode symbol K is 1 (step), and if K is not 1 but 0, the return traveling is started at high speed as in the conventional example (step), and the process proceeds to step.

If K = 1, the return travel is started at a low speed (step).

When the return runs at low speed, the paper feed sensor 6
Waiting until the paper feed sensor is turned off after passing through (step), the scanning position of the optical system at the simultaneous point is judged by the value of the symbol R (step).

The value of R is determined by the registration-ratio sensor interrupt routine shown in FIG. 10, and is interrupted each time the optical system passes the position of the registration-ratio sensor 5 shown in FIG. The previous value of R is judged (step) and if R = 0, the value of R is set to 1 (step), and if R = 0, the value of R is set to 0 (step).

At that time, as shown in FIG.
When the optical system is present on the left side where the return end sensor 4 is located, the value of R becomes 0, and when it exists on the right side, the value of R becomes 1 in advance.

Therefore, when the value of R is discriminated in the step of FIG. 9 and the value is 1 instead of 0, the optical system has not yet returned to the position of the registration resolution sensor 5, which means that the return speed is changed from low speed to high speed. Switch to (step).

Next, the value of Z is discriminated (step), and when Z = 0 and it is not necessary to feed the next sheet, the process jumps to step Z = 0.
If not, the optical system passes the position of the registration ratio sensor 5 and waits until the value of R becomes 0 (step), drives the feed roll (step), and proceeds to step.

When the value of R is already 0 in step, the process proceeds to step, and if the value of Z is determined and Z = 0, the feed roll is immediately driven (step), and the process proceeds to step, Z = If it is 0, it jumps to the step as it is.

When moving from step to step, when the paper has the maximum length, as described above, the optical system passes the registration ratio sensor 5 so that the paper passes the paper feed sensor 6 immediately after R = 0. As a result, it is possible to perform alignment without disturbing the start of paper supply for the next skimming run. In this case, the return speed is not switched.

In step, the optical system reaches the position of the return end sensor 4 and waits for the sensor 4 to turn on, then the return traveling is stopped (step), and the value of Z is determined in the next step, and if Z = 0. Program progress stopped, Z
If the value of is not 0, the process returns to step, and the same operation as described above is performed until the copy set number Z is exhausted and the process is completed.

As described above, when the length of the paper is longer than the scanning distance, the return speed is changed in two steps except when it is the maximum length, and the time of the change is adjusted to the length of the paper (step, It is also possible to prevent the copying time from becoming long by making the optical system stand by at the return end position and not aligning with the next sheet, and by slowing the return speed.

EFFECTS OF THE INVENTION The present invention uses return travel two-stage gear shifting in scanning of the optical system, regardless of the distance traveled by the optical system and the size of the paper.
By changing the shift time point from low speed to high speed according to the length of the paper, the timing at which the optical system returns to the travel limit position can be adjusted appropriately to the length of the paper, and the optical system is set to the standby state during continuous copying. Since there is no need to keep it, it is possible to prevent problems due to heat generation by the exposure lamp, and it is possible to perform efficient copying work without increasing the copying time.

[Brief description of drawings]

FIG. 1 is a diagram corresponding to the claims of the present invention, and FIG. 2 is a schematic explanatory diagram of a main part of a dry electrophotographic copying machine, FIG. 3, FIG. 4 and FIG.
FIG. 6 is a diagram showing a conventional scanning drive of an optical system and timing chart of a predetermined signal, FIG. 6 is a diagram showing an arrangement of sensors provided in a scanning path in an embodiment according to the present invention, and FIG. 7 is this embodiment. FIG. 8 is a block diagram of the control system of FIG. 8, FIG. 8 is a diagram showing the scanning drive of the optical system and timing charts of predetermined signals in this embodiment, and FIGS. 9 and 10 are flow charts of the control program of this embodiment. Is. 01 …… Platen glass, 02 …… Original, 03 …… Exposure lamp, 04 …… Mirror, 05 …… Drum-shaped photoreceptor, 06 …… Charge corotron, 07 …… Developer, 08 …… Transfer corotron, 09 …… Paper tray, 010 …… Feed roll, 011…
… Photo sensor, 1… Platen glass, 2… Exposure lamp, 3… Scan end sensor, 4… Return end sensor,
5 ... Registration sensor, 10 ... CPU, 11 ...
… ROM, 12 …… RAM, 13 …… input interface, 14 ……
Output interface, 15 ... Scanning motor, 16 ... Feed roll driving motor.

Claims (2)

[Claims] 1. An electrophotographic copying machine having a scanning optical system for reading an image, a scanning position detecting means for detecting a scanning position of the optical system, and a paper feed for detecting a supplied sheet at a predetermined position before transfer. Position detection means, scan control means for controlling scan drive of the optical system, scan drive means for driving the optical system under the control of the scan control means, information from the scan position detection means and the paper feed position Information is input from the detection means, the scanning return speed of the optical system is determined based on both the information, and the information processing means outputs the speed signal to the scanning control means. If the paper feed position detection means detects a sheet at the time of returning to the return traveling, the speed is changed to the high speed return traveling at the time when the sheet feeding detection means does not detect the sheet at first when the sheet is detected as the low speed return traveling. You The optical scanning controller, characterized in that. 2. The information processing means, if the scanning position of the optical system detected by the scanning position detecting means has returned to a predetermined position when the paper feeding detecting means stops detecting a sheet. 2. The optical system scanning control device according to claim 1, wherein the control is performed so that the vehicle travels back at a low speed.