JPS6360474A - Copying machine - Google Patents

Abstract

PURPOSE:To shorten the scanning length, and to realize the speed-up of continuous copying by constituting the titled machine so that an exposure scan start position of an optical system scanner can be switched to a first exposure scan start position for executing an exposure scan from a first reference density original, and a second exposure scan start position for executing an exposure scan from a second reference density original. CONSTITUTION:On one side in the scanning direction of an original platen 1, the first reference density original A and the second reference density original B are provided in parallel in this order from the upper side in the scanning direction. These first reference density original and the second reference density original B are constituted by putting directly a suitable color to the lower face of one side in the scanning direction of the original platen 1, or sticking a small piece which has been colored to a suitable color. In this case, an exposure scan start position of an optical system scanner 6 is switched to the first exposure scan start position for executing an exposure scan from the first reference density original A, and the second exposure scan start position for executing an exposure scan from the second reference density original B, in accordance with the time of starting and ending the copying operation, and the time when a continuous copying operation is being executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a technology for increasing the copying speed during continuous copying as part of increasing the speed of copying machines.
A first standard density original and a second standard density original are placed on one side of the original table in the scanning direction.
Reference density originals are arranged side by side in this order from the upper side in the scanning direction, and a first detector for detecting a surface potential of an electrostatic latent image corresponding to the first reference density original is provided around the photoreceptor; Second
A second detector for detecting a developed density corresponding to a reference density original is provided, the amount of light from the light source is controlled based on the detection result of the first detector, and the toner density is controlled based on the detection result of the second detector. The present invention relates to an improvement of a copying machine with a movable optical system configured as described above.

[Conventional technology]

In recent years, various measures have been taken to increase the speed of copying machines. However, due to the relationship with the power source, it is said that these measures alone will soon reach the limit of speeding up.

In view of the current situation, the inventors of the present invention have carefully studied and considered conventional copying machines in order to further increase the speed of copying machines. A density original and a second reference density original are arranged side by side in this order from the upper side in the scanning direction, and the surface potential of an electrostatic latent image corresponding to the first reference density original is detected around the photoreceptor. 1st
a detector and a second detector for detecting a developed density corresponding to the second reference density original; the amount of light from the light source is controlled based on the detection result of the first detector; It has been found that there is room for improvement in the following points in a copying machine with a movable optical system configured to control toner density based on the following points.

That is, in the above-mentioned conventional copying machine, the exposure scanning start position of the optical system scanner is set below the first reference density original (the position where exposure scanning is performed from the first reference density original);
Even when copying - sheets of originals or when making continuous copies of many sheets from - sheets of originals, the optical scanner starts moving from the lower position of the first base density original. It was configured to return to a position below the original.

By the way, since the toner concentration (the ratio of toner in a two-component developer consisting of toner and carrier) may change in a short period of time, it is desirable to constantly and continuously control it. Therefore, in current copying machines, the optical system scanner performs exposure scanning of the second standard density original for each copying operation, and each time the second standard density original is exposed and scanned,
Alternatively, for the purpose of saving toner consumption and reducing the load on the cleaning device, an image corresponding to the second standard density document may be formed on the surface of the photoreceptor once every several exposure scans. The developed density is optically detected by a detector such as a reflective photosensor, and the amount of toner supplied to the developing device is adjusted based on this detection result, thereby controlling fluctuations in toner density within a certain range. ing.

On the other hand, since changes in light intensity due to light source deterioration do not appear in a short period of time, there is no need to control the light source light intensity (so-called AVH correction) for each copying operation unless the copying magnification is changed. By the way, with current copying machines, the -th copy is executed only when a certain amount of time (usually set to about 3 minutes) has elapsed since the last copy was completed, or when the copy magnification is changed. The AVR is configured to be corrected prior to the copying operation. In other words, the optical scanner is the 1st Jj41! When the light source is turned on while the original is stationary below the density original, an electrostatic latent image corresponding to the first reference density original is created, the surface potential is detected, and AVR correction is performed. has been done.

However, in conventional copying machines, as mentioned above, the exposure scanning start position of the optical system scanner is set below the first reference density original, so during continuous copying operation, the exposure scanning start position of the first reference density original is Even though the amount of light from the light source was not controlled (AVH correction), the optical scanner returned to the position below the first reference density original.

Therefore, in the above-mentioned conventional example, when performing continuous copying, the moving path portion of the optical system scanner on the upper side in the scanning direction than the second standard density original (the optical system required for preliminary scanning of the first standard depth original) The portion of the scanner's travel path) is independent of the AVR's IR positive, and this portion can be considered an unnecessary scan length during continuous copying operations.

Since the width (width in the scanning direction) of the first standard density original is at most a few + 1, the time required for the optical scanner to move this area is the copying time per -sheet (-sheet width). Although it accounts for a small percentage of the time required to make a copy, for example, when making continuous copies of several hundred copies, it is caused by the reciprocating movement of the optical scanner in the above-mentioned area. It is clear that the time loss will be too large to be ignored.

[Problems to be Solved by the Invention] In view of the above-mentioned conventional drawbacks, the present invention provides an optical The aim is to speed up continuous copying by shortening the scanning length of the system scanner.

[Means for solving problems]

The technical means taken by the present invention to achieve the above object are as follows.

That is, in the copying machine described at the beginning, the present invention sets the exposure scanning start position of the optical system scanner at the start and end of the copying operation and during continuous copying operation, so that the exposure scanning is performed from the first reference density original. The present invention is characterized in that it is configured to switch between a first exposure scan start position and a second exposure scan start position for performing exposure scan from a second reference density original.

[Effect]

According to the above configuration, if - copies are to be made,
The optical scanner starts moving from the first exposure scan start position, returns to the 1nth light scan start position, and stops; however, during continuous copying, the optical scanner moves to the second exposure scan start position. By returning, it starts moving in the scanning direction from the second n-light scanning start position again, continues copying the second and subsequent sheets, and returns to the first exposure scanning start position only when the entire number of sheets has been copied. It will stop.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

Figure 1 is a schematic diagram of the configuration of a copying machine with a moving optical system. Figure 2 is a diagram of the configuration of the main parts showing the exposure scan start position of the optical scanner. Figure 3 is a diagram of the movement control circuit of the optical scanner. This is a flowchart.

In Fig. 1, 1 is an original table made of transparent glass, etc.;
3 is a moving optical system; an optical system scanner 6 is equipped with a light source 4 for slit exposure and a mirror 5;
Moving mirror 7.8, fixed mirror 9, variable magnification lens group 10
It is composed of etc.

Reference numeral 11 denotes a drum-shaped photoreceptor that rotates in the direction of the arrow, and around it are a charging device 12, a developing device 13, a transfer device 14,
A copy paper separation device 15 and a cleaning device 16 are arranged. 17 transfers the copy paper in paper feed cassette 8 to transfer device 1;
4, a paper feed conveyance device 19 conveys the copy paper after transfer and separation to a fixing device 20, and 21
is the paper output tray.

As shown in FIGS. 1 and 2, on one side of the document table 1 in the scanning direction, a first standard density original A and a second standard density original B are arranged side by side in this order from the upper side in the scanning direction. has been done.

The first standard density original A and the second standard density original B are printed directly on the lower surface of one side of the document table 1 in the scanning direction in an appropriate color (for example, the first standard density original A is gray, the second standard density original B is black) or by pasting small pieces colored in appropriate colors (gray and black as mentioned above).

Around the photoreceptor 11, the first group ]1! A first detector 21a detects the surface potential of the electrostatic latent image corresponding to the density original A, and a second detector 21a detects the fourth degree of development corresponding to the second standard density original B (the second detector is ,for example,
A reflective photosensor consisting of a combination of a light emitting diode and a photodetector is used. ) 21b are provided. Then, the amount of light from the light source is controlled based on the detection result of the first detector 21a, that is, so-called AVH correction is performed, and the developing device 13 is controlled based on the detection result of the second detector 21b.
By adjusting the amount of toner supplied to the toner, the toner density (ratio of toner in a two-component developer consisting of toner and carrier) can be controlled to be substantially constant. A blank cut lamp 22 is provided between the first detector 21a and the developing device 13, and in addition to being used for its original purpose, the blank cut lamp 22 is used to irradiate the photoreceptor 11 with light to convert the first reference density original A into a blank cut lamp. It is also configured to erase the corresponding electrostatic latent image.

In FIG. 2, reference numeral 23 indicates a holding plate for fixing the document table 1 to the upper surface of the copying machine main body, 24 indicates a document, 25 indicates a control circuit for the amount of light from the light source, and 26 indicates a control circuit for toner density.

In this embodiment, in the copying machine configured as described above, the exposure scanning start position of the optical system scanner 6 is changed from the first standard density document A at the start and end of the copying operation and during the continuous copying operation. The present invention is characterized in that it is configured to switch between a first exposure scan start position for performing exposure scans from the second reference density original B and a second exposure scan start position for performing exposure scans from the second reference density original B. To explain more specifically, photointerrupters PI+ and Pli are provided below the first reference density original A and the second reference density original B, respectively, to detect the position of the optical scanner 6, and the copying operation is started. And at the end of the process, the optical system scanner 6 is detected by the photo ink club Pit under the first reference source kl, and the upright position of the photo ink club PI is the 1nth light scanning start position, During other continuous copying operations, the optical scanner 6
is the photo ink printer P1 below the second reference density original B. A movement control circuit C is provided to control the movement of the optical system scanner 6 so that the second exposure scan start position is detected by the first photo ink printer Pls.

Next, the operation of the copying machine having the above configuration will be explained with reference to the flowchart shown in FIG. In the following, 81~s
S indicates a step in the flowchart.

First, the original 24 is placed on the original table 1 and the print switch is turned on. In step S, the optical system scanner 6
It is determined whether or not there is at the 1nth light scanning start position, and if the optical system scanner 6 is not at the 1nth light scanning start position,
In other words, for some reason, the optical scanner 6
If it is stopped at a position other than the exposure scan start position,
The optical scanner 6 is returned to the first exposure scan start position (the position detected by the photointerrupter PI).

When the optical system scanner 6 is at the first exposure scan start position, it is detected by the photointerrupter PI (S,), so that the exposure scan is started (Sz).

To explain more specifically, in the configuration of the present invention, if the optical scanner 6 is at the first exposure scan start position, the light source 4 is turned on at the same time as the print switch ○N, and the optical scanner 6 is turned on at the first t@light. While stationary at the scanning start position, an electrostatic latent image corresponding to the first reference density original A is formed on the photoreceptor 11, and the first detector 21a detects the surface potential of the image. Control of light source light amount based on AVR
correction) is performed.

Next, the optical system scanner 6 exposes and scans the second standard density original B to form an electrostatic latent image corresponding to the second standard density original B on the photoreceptor 11, which is developed by the developing device 13. This developed density, that is, the density of the visible image formed on the surface of the photoreceptor 11 corresponding to the second 1!1 degree original B is optically detected by the second detector 21b, and the detection result is Based on this, toner is replenished to the developing device 13, and the toner concentration in the developer is controlled so as to suppress fluctuations within a certain range. The toner of the image corresponding to the second reference density original B is removed from the surface of the photoreceptor 11 by the cleaning device 16 .

Thereafter, the copy paper is fed toward the transfer device 14, the original 24 is exposed and scanned, and a copying operation is performed on the copy paper.

When the exposure scan to the edge of the original 24 is completed (S3),
In step S, it is determined whether the remaining number of copies is zero. For example, if - copies are to be made, the remaining number of copies is zero, so the optical scanner 6 1 Exposure scan start position (Photo ink printer P
It returns to the position detected by TI) and stops (S,), but
If continuous copying is in progress, the number of remaining copies is not zero, so the exposure scanning start position of the optical system scanner 6 is set to the second position.
The optical system scanner 6 is switched to the exposure scan start position, stops at the second exposure scan start position (the position detected by the photointerrupter P), and starts the exposure scan again.

Note that the copying machine includes one that controls the toner density by exposure scanning of the second standard density document B for each exposure scan, and one that reduces toner consumption and is equipped with a cleaning device 1.
As mentioned above, in order to reduce the load of 6, some exposure scans are performed once every several exposure scans. In the case of the latter type of copying machine, exposure scanning of the second reference density original B is performed every copying operation, but the electrostatic latent image corresponding to the second reference density original B formed on the surface of the photoreceptor 11 is is erased by the blank cuff lamp 22, and the electrostatic latent image corresponding to the second reference density original B is developed once every several exposure scans.

Then, when the remaining number of copies becomes zero, that is, when all the copies have been completed, the optical scanner 6 returns to the first exposure scan start position (the position detected by the photo ink printer PI+) and stops. (S,).

Therefore, if the scanning length of the optical scanner 6 when copying the first sheet is shown in FIG. The scanning length L2 of the optical scanner 6 is shortened, and the speed of continuous copying is increased.

In FIG. 2, the second exposure scan start position is set at the boundary between the first reference density original A and the second reference density original B, but the present invention is not limited to this, and the above-mentioned It is also possible to set a position slightly biased toward the upper or lower side of the boundary in the scanning direction as the second n-light scanning start position. That is, as shown in FIG. 4, the optical scanner 6 is set to move at a high speed at the start of movement, and after stabilizing at a predetermined speed, to perform exposure scanning for the second reference density original B and onwards. is normal. On the other hand, the width 11 of the first standard density original A and the width 1t of the second standard density original B are usually each 25 m-
Generally, only the intermediate portion of each width of 11° and 12° is used for detection by the first detector 21a and the second detector 21b.

Therefore, in the width 12 of the second reference density document B, by the time the moving speed of the optical system scanner 6 reaches this area on the upper side in the scanning direction than the area actually used for detection by the second detector 21b. In principle, it is possible to select the second exposure scan start position as long as the position is away from the area by a distance necessary for stability.

Further, in the above embodiment, there are two photointerrupters Pit for detecting the position of the optical system scanner 6.

Although the first exposure scan start position and the second exposure scan start position 1 of the optical system scanner 6 are set using PI, the present invention is not limited to this. By using an encoder in the motor and adding the number of pulses of the encoder when the optical scanner 6 moves in the scanning direction, the moving distance of the optical scanner 6 in the scanning direction is determined, and when the optical scanner 6 returns, In a copying machine in which the braking timing of the optical scanner 6 is controlled by subtracting the number of pulses, the stopping position of the optical scanner 6 during continuous copying operation can be determined by setting the number of pulses to be subtracted. It is possible to set the 2-exposure scan start position.

〔Effect of the invention〕

The present invention has the above-described configuration, and during continuous copying operation, the optical system scanner returns to the second exposure scan start position and starts moving in the scanning direction from the second exposure scan start position again, Since I will continue copying the second and subsequent copies,
The scanning length of the optical scanner is shortened, making it possible to speed up continuous copying.

[Brief explanation of the drawing]

1 to 4 show one embodiment of the present invention, FIG. 1 is a schematic diagram of the configuration of an optical system mobile copying machine, and FIG. 2 is a configuration of main parts showing the exposure scan start position of an optical system scanner. A schematic diagram, FIG. 3 is a flowchart executed by the movement control circuit of the optical scanner, and FIG. 4 is a diagram for explaining the movement speed of the optical scanner. A...First reference density original, B...Second reference density original, C...Movement control circuit, 1...Original table, 4...
Light source, 6... Optical scanner, 11... Photoreceptor,
13... Developing device, 21a... First detector, 21b
...Second detector.

Claims (1)

[Claims] A first standard density original and a second standard density original are placed on one side of the original table in the scanning direction.
Reference density originals are arranged side by side in this order from the upper side in the scanning direction, and a first detector for detecting a surface potential of an electrostatic latent image corresponding to the first reference density original is provided around the photoreceptor; Second
A second detector for detecting a developed density corresponding to a reference density original is provided, the amount of light from the light source is controlled based on the detection result of the first detector, and the toner density is controlled based on the detection result of the second detector. In a copying machine with a movable optical system, the exposure scanning start position of the optical system scanner is adjusted at the start and end of a copying operation, and during continuous copying, to the first position for exposure scanning from a first reference density original. 1. A copying machine characterized in that the copying machine is configured to switch between a first exposure scan start position and a second exposure scan start position for performing exposure scan from a second reference density original.