JPH01114875A - Copying machine - Google Patents

Abstract

PURPOSE:To prevent the transcription of an unnecessary image caused by scanner return, etc., by halting a scan optical system for a limited time after scanning is finished, reflecting light from an exposure source by means of a reflecting member and exposing a photosensitive body during said limited time. CONSTITUTION:When a scanner 11 scans, the detection of the tailing edge of paper by means of a paper sensor 32, or the position detection of the scanner 11 by a maximum scan sensor 35 is performed. The instant that the detection by the sensor 35 is performed, the movement of the scanner 11 is halted, and time is set on a return starting timer; the time is needed for an area in which the unnecessary image may be formed to pass an exposure position. While the return starting timer counts, a light source 12 is lighted. The light from the light source 12 is reflected by a reflecting plate 36, and a photosensitive body drum 1 is exposed. During the same time, the returning operation of the scanner 11 is not started. Thereby, the appearance of the unnecessary image in copy paper can be prevented without providing an inter-image eraser.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a copying machine having an electrophotographic process, and in particular, to a copying machine that uses an electrophotographic process to prevent unnecessary images from appearing on a photoreceptor or copy paper after scanning by an optical system. Regarding copying machines.

[Conventional technology and its problems]

Generally, in a copying machine, the i3! The placed original is scanned by a scanning optical system, and light from an exposure source is reflected on the original surface to expose the charged photoreceptor.

In such copying machines, the scanning length of the scanning optical system, such as a scanner, is generally set to be slightly longer than the length of the image area determined by the size of the copy paper and the copy magnification. . Further, after the scanning is completed, the scanner returns to the scanning starting point, and the exposure source is generally turned on until the scanner returns halfway.

However, when making reduced copies, if the copy paper is large and its length is longer than the image area, the original image may be copied onto the copy paper when the scanner returns, and this unnecessary image may cause the copy There is a problem in that the image becomes unsightly, degrading the quality of the copy, and toner is wasted. Furthermore, even when the document cover is opened immediately after scanning by the scanner is completed, the same problem as described above may occur.

Japanese Unexamined Patent Publication No. 55-69169 describes a copying machine in which after scanning by a scanner is completed, the scanner is stopped at that position until the exposure source is turned off, or is caused to travel in the forward direction by inertia.

However, according to this conventional copying machine, although it is possible to prevent the original image from being copied when the scanner returns, images may appear when the scanner is stopped or when it is running after scanning. If the document cover was opened immediately after the document was finished, a black pixel image would sometimes be formed.

By the way, large-sized copying machines are equipped with an inter-image eraser to erase unnecessary images in order to realize many functions such as image editing functions. The unnecessary images are erased to prevent toner from adhering to them. However, in small-sized, low-cost copying machines, the above-mentioned problem is often not provided with an inter-image eraser.

[Technical means for solving the problem] In view of the above-mentioned problem, the present invention prevents unnecessary images from appearing on copy paper due to returning the scanner or opening the document cover without providing an inter-image eraser. The technical means for this purpose include a detection means for detecting the end of scanning a document of maximum length that can be copied, and a scanning optical system that stops at a predetermined position for a certain period of time after the end of scanning. The apparatus is characterized by comprising a control means and a reflecting member for reflecting light from an exposure source and exposing a photoreceptor while the scanning optical system is stopped.

[For production]

The detection means detects the end of scanning the maximum length of the document that can be copied by the copying machine. As a detection means,
A limit switch that detects when the scanner reaches such a position, a timer that is set to the time from the start of scanning, etc. are used. After the scanning is completed, the scanning optical system is stopped for a certain period of time by the control means, and during that time, the light from the exposure source is reflected by the reflecting member to expose the photoreceptor, thereby eliminating the electric charge on this part of the photoreceptor. This prevents unnecessary adhesion of toner and transfer to copy paper.

〔Example] Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a front sectional view showing the general structure of a copying machine.

In the figure, a photoreceptor drum l that can be rotated counterclockwise is arranged approximately in the center of the main body of the copying machine, and around it are an eraser lamp 2, a charger 5, a developing device 6, and a transfer charger 7. , a blade type cleaning device 9 is provided. The photoreceptor drum 1 has a photoreceptor layer provided on its surface, and is uniformly charged by passing through an eraser lamp 2 and a charger 5, and then subjected to image exposure from an optical system 10.

The optical system 10 is installed below the original glass 16 so as to be able to scan the original image, and includes a scanner 11 having a light source 12 and a movable mirror 13, a slider 41 having movable mirrors 42 and 43, a lens 14, and a mirror. It consists of 15. The scanner 11 is driven by a scan motor so that the slider 41 moves at a speed that is half the speed of the scanner 11 so that the scanner 11 moves at a speed that is a constant ratio according to the copying magnification relative to the peripheral speed of the photoreceptor drum 1. Driven by M3.

On the other hand, there are paper feed rollers 21 on the left side of the copying machine body.
．． An overprint paper section 20 and an underprint paper section 22 are installed, and the copy paper conveyance path is composed of rollers 24 and 25, a timing roller 26, a conveyance belt 27, a fixing device 28, and a pair of discharge rollers 29. There is. In addition, 30 is a discharge tray,
31 is a manual paper feed unit, 32 is a timing roller 2
A paper sensor detects the trailing edge of the paper (copy paper) at position 6, a discharge sensor 37 detects the discharge of the paper, Pl indicates the exposure position, and P2 indicates the transfer position.

Also, in the scanning path of the scanner 11, there is a registration sensor 3 that detects the position of the scanner 11 in order to accurately imprint the image on the paper at the same magnification.
3. At the time of reduction magnification (for example, 0.64 times), a registration sensor 34 similar to the above-mentioned registration sensor 33, and a maximum sensor for detecting that the scanner 11 has reached the scanning end position of the maximum document length that can be copied. A scan sensor 35 is provided.

On the back side of the copier main body cover on the end side of the original glass 16, there is a white reflective Fi3 made of a heat-resistant plastic plate or the like.
6 is attached and the scanner 11 is below this reflector 36, the light from the light source 12 will be reflected by the reflector 36.
The photoreceptor drum 1 is exposed to light.

FIG. 2 shows a circuit diagram of the control section of the copying machine.

The above-mentioned sensors 32, 33, 34, 35, 37 and other sensors (not shown) and switches on the operation panel are arranged as a switch matrix 204, and the input switch scan signal SC from CP 0201 is arranged as a switch matrix 204.
The on/off states of the respective sensors are read into the CPU 2 O5 from the input ports IO-4.

Data such as the number of copies and copy magnification are displayed by the display device 72 based on the display segment signal S Ga % g and the display scan signal SDO~3.

The speed and rotation direction of the scan motor M3 that drives the scanner 11 are controlled by a motor drive circuit 205. By varying the pulse width of the drive signal from the CPU 2 O 5, the rotation speed of the scan motor M3 is varied, and by setting the forward/reverse signal to a high or low level, the scan motor M3 rotates forward or reverse. As a result, the scanner 11 moves at a predetermined speed in the scan direction or return direction. When the scanner 11 is stopped, a brake is applied by the counter electromotive force of the scan motor M3, so that the scanner 11 is quickly stopped. In addition, scan motor M3
is provided with a rotary encoder 207, which outputs pulses corresponding to the rotation of the scan motor M3, which are amplified and waveform-shaped by a waveform shaping circuit 206 and sent to the CPU 2.
It is input to the interrupt input terminal of O5.

3a, b and 4a, b show the relationship among the exposure position P1 on the photosensitive drum 1, the transfer position P2, the paper, and the position of the scanner 11 when the paper is longer than the image area. It is a diagram.

Based on these figures, the control operation of Scanner II and how it prevents the generation of unnecessary images will be explained.

Figure 3 a, b and Figure 4 a, b show examples of unnecessary images being transferred onto paper. Occurs when you go.

3a and 3b show a case where the paper sensor 32 does not detect the trailing edge even though the maximum scan sensor 35 detects the end of scanning. In this case, if the scanner 11 immediately When the return operation starts, an image is formed during the return operation in the area on the photosensitive drum 1 corresponding to La in FIG. 3, and this image is transferred to the paper.

In addition, in FIG. 4a, when the paper sensor 32 detects the rear end of the paper, the scanner 11 is still located in front of the maximum scan sensor 35, and the scanner 11 remains at the remaining distance (Ll- A case is shown in which the maximum scan sensor 35 detects the end of scanning the original while the original is being scanned by L2). In this case, if the return of the scanner 11 is started immediately after the maximum scan sensor 35 is turned on, an image during the return operation will be formed in the area on the photoreceptor drum l corresponding to La (La+Lb) in Figure 4. , of which the portion corresponding to La will be transferred onto the paper.

If the document cover is opened immediately after scanning and the document is removed for replacement or the like, a black flat image will be formed in the area corresponding to La.

In either case, the quality of the copy deteriorates and toner is wasted.

Therefore, in this embodiment, by delaying the start of the return operation of the scanner 11, the image being returned is not imprinted (not formed) on the photoreceptor drum l, and the maximum scan sensor 35 is turned on. Sometimes, the scanner 11 is stopped below the reflection plate 36 until the area corresponding to L3 on the photosensitive drum 1 passes through the exposure position WPI to prevent unnecessary images from being captured.

Next, the processing procedure of the copying operation in the CPU 201 will be explained, focusing on the control operation of the scanner 11, according to the flowcharts shown in FIGS. 5 to 7.

Figure 5 schematically shows the entire processing of the CPU2O5, and when the power is turned on and the program starts,
First, in step #1, the initial state of the CPU 2O5 is set, the number of copies is initialized to 1, and all control objects are initialized, such as returning the document table to the starting position. In step #2, an internal timer is set to define the length of one routine. Then step #
Step 3 counts up timer 2 used to control the copying machine. In step #4, determine the value of the main counter,
Control is performed by dividing into five parts according to each value of "0" to "4".

When the main counter is "0", input processing from the switch matrix 204 and setting of display data based on the input data are performed (steps #5 and #6). When the main counter is "1", display processing of the hundredth digit on the display device 72 and mode-specific processing according to the operation mode of the copying machine are performed (steps #7 to #8).

When the main counter is "2", display processing of the tens digit on the display device 72, jam detection, and trouble detection are performed (
Steps #9-11). When the main counter is "3", display processing of the first digit on the display device 72, AIDC control,
and toner empty control (step #12~
14). When the main counter is "4", LED lighting display processing, input key processing, manual feed processing, and temperature control are performed (steps #15 to #18).

After completing each of the above processes, perform the process for scanner return control and the process for registration control (
Steps #19-20). When these series of processes are completed, the main counter is counted up in step #21.
), wait for the main timer to time up (step #22), and if the time is up, return to step #3,
Thereafter, these processes are repeated. Note that when the main counter is "4", it is set to "0" in step #21.

FIG. 6 is a flowchart showing in detail the mode-specific processing of step #8 described above.

In step #51, the value of the operation mode is determined. Normally,
The operation mode is "0" and is set to "1" when a trouble is detected in the trouble detection routine of step #ll, and is set to "1" when a trouble is detected in the trouble detection routine of step #11. When a replenishment key (not shown) is input, each is set to "2", "3", or "4".

When the operation mode is "O", it is a normal copy operation,
Feed and transport the paper (step #52),
Control the area around the photoreceptor drum 1 (step #53)
.

When the operation mode is "1", it means that a trouble has occurred, and a trouble handling routine is executed (step #54).
).

When the operation mode is "2", it is during function execution, and function processing is executed (step #55).
, When in the continuous copy mode in which multiple copies are made from one document (YES in step #56), the process jumps to step #52 to continue copying.

When the operation mode is "3", a drum drying routine is executed (step #57).

When the operation mode is "4", a forced toner replenishment routine is executed (step #58).

FIGS. 7a and 7b are flowcharts showing the scanner return control routine in step #19 in detail.

When the processing state is "0", it is determined whether the scanner 11 is scanning (scanning) (step #72
). If scanning is in progress, the paper sensor detects the trailing edge of the paper (step #73) or the maximum scan sensor 35 detects the position of the scanner 11 (step #74).

When the trailing edge of the paper is detected in step #73, set a timer until the scanner 11 stops, that is, a scanner stop timer (step #75).
, set the processing state to "2" (step #76).

When the detection by the maximum scan sensor 35 is performed in step #74, the movement of the scanner 11 is immediately stopped, a timer until the scanner 11 starts returning, that is, a return start timer is set, and the processing state is changed to " 1” (steps #77 to 79).

When the processing state is "1", it is determined whether the return start timer is zero (step #82), and if it is not zero, the return start timer is subtracted by one (step #83). . Next, the trailing edge of the paper is detected by the paper sensor 32 (step #84), and if the trailing edge of the paper is detected, the processing state is set to "3" (step #85).

When the processing state is "2", it is determined whether the scanner stop timer is zero (step #92), and if it is zero, the movement of the scanner 11 is stopped (step #9).
5) Set the return start timer in step #
96), set the processing state to "3" (step #9
7).

If it is not zero in step #92, the scanner stop timer is subtracted by one (step #93), and it is determined whether the maximum scan sensor 35 is on (step #93).
94). If it is on, execute step #95 and below as if the scanner stop timer was zero,
If it is not on, processing state "2" continues as is.

Here, in order to eliminate toner consumption outside the image area, a return start timer is set when the scanner stop timer reaches zero (step #
92, 96), when the paper sensor 32 detects the trailing edge of the paper and starts returning the scanner 11 without the maximum scan sensor 35 being turned on, it is not necessary to set the return start timer.

When the processing state is "3", it is determined whether the return start timer is "0" or not (step #102); if it is not zero, the return start timer is subtracted by one (step #103); if it is zero, the return start timer is subtracted by one (step #103); , start the return of the scanner 11 (step #104), and set the processing state to "0".
” (Step #105).

The return start timer used here is a timer that is set when the maximum scan sensor 35 is turned on, and normally the charger 5 is also turned off at the same time. At that point, the area between the exposure position P1 and the position of the charging charger 5 is charged, and this is an area where an unnecessary image may be formed. Therefore, the time required for this area to pass through the exposure position P1 is set in the return start timer, and while the return start timer is counting, the light source 12 is turned on and the return operation of the scanner 11 is not started. This prevents unnecessary images from being formed.

In addition, in the case of continuous copy mode, since there is a small possibility that the operator opens or closes the document cover during copying, the scanner return control in step #19 described above is executed only for the last sheet of continuous copying. do it.

In the above embodiment, the maximum scan sensor 35 is used as a detection means for detecting the end of scanning of a document having the maximum length that can be copied. A timer may be used to measure the time it takes to reach the position. This makes it possible to reduce costs.

In the above-mentioned embodiments, a method in which the scanner 11 having the light [12] moves to perform scanning has been described, but it is also applicable to a method in which the document table moves.

〔Effect of the invention〕

According to the present invention, it is possible to prevent unnecessary images from appearing on copy paper due to returning the scanner or opening the document cover without providing an inter-image eraser. Therefore, it is possible to reduce costs without degrading the quality of copies, and to prevent unnecessary consumption of toner.Furthermore, since the document cover can be opened after scanning is completed, replacing the document can be done smoothly. I can do it.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a front cross-sectional view showing an example of a schematic configuration of a copying machine; FIG. 2 is a circuit diagram of a control section of the copying machine; FIGS. 3a, b, and 4. Figures a and b are diagrams for explaining the relationship between the length of paper and the control operation of the scanner, and Figures 5 to 7 a and b are flowcharts showing the control operation of the copying machine. P... Paper (copy paper), Pi... Exposure position, P
2...Transfer position, 1...Photoconductor drum (photoconductor),
11... Scanner (scanning optical system), 12... Light source (exposure [), 32... Paper sensor, 35...
- Maximum scan sensor (detection means), 36... Reflection plate (reflection member), 201... CPU (control means). Figure 3 2? 40a Figure 3 Figure 4 b

Claims (1)

[Claims] a detection means for detecting the end of scanning a document of maximum length that can be copied; a control means for stopping the scanning optical system at a predetermined position for a certain period of time after the end of scanning; and a control means for controlling the light of the exposure source while the scanning optical system is stopped 1. A copying machine comprising: a reflecting member for reflecting light and exposing a photoreceptor to light.