JPS61198223A - Scanning method for moving scan optical system of image forming device - Google Patents

Abstract

PURPOSE:To shorten considerably the time required for scanning by using a return stroke up to a position after the copying operation end of the 2nd image surface for the measurement of density information for the 1st image surface and the adjustment of exposure. CONSTITUTION:The 1st optical system scan start position (b) is set at specific distance alphaupstream from a center reference position on a stationary original setting part 22 for aligning centers of two image surfaces in the scanning direction of the moving scan optical system 1 which makes an exposure optical scan on the original surface correcting to the two image surfaces set on the stationary original setting part 22 from the 1st image surface A to the 2nd image surface B. Further, the 2nd optical system scan start position (a) is set at an interval of the 1st image surface A and the specific distance alpha upstream from the center reference position X. Then, an exposure optical scan on the 2nd image surface B is made from the position (b) by the exposure optical system 11 to complete the exposure optical scan on the 2nd image surface and the scanning operation system 11 is moved back to the position (a), and an exposure optical scan on the 1st image surface A is made from the position (a) to complete the exposure optical scan on the 1st image surface A, and the scanning optical system 11 is moved back to the position (b).

Description

Detailed Description of the Invention (a) Industrial Application Field The present invention relates to a scanning method of a moving scanning optical system in an image forming apparatus such as an electronic copying machine. In the image forming apparatus, the image forming apparatus includes a stationary original setting section having a document setting area corresponding to the original setting area, and a moving scanning optical system for exposing and optically scanning the surface of the original set in the original setting section. The present invention relates to a scanning method of a movable scanning optical system in an image forming apparatus that forms images corresponding to images of a set original on different surfaces of a transfer material.

(B) Prior Art Conventionally, as shown in FIG. 2, a copying machine 1 has a stationary document placement section 2 at the top, a paper feed section 3 and a paper ejection section 5 at both sides.
The interior includes a moving scanning optical system 6, a fixed optical system 7, an image forming section 9, a fixing section 10, etc., and the moving scanning optical system 6 scans the original placed on the stationary original placing section 2. The obtained optical image is converted into a toner image by the image forming section 9 via the fixed optical system 7, and the toner image is transferred onto a transfer material conveyed from the paper feed section 3, and then transferred by the fixing section 10. After the image is firmly transferred to the transfer paper, it is configured to be discharged to the paper discharge section 5.

In particular, images of the left and right sides of a manuscript, such as a bound book spread, can be copied onto different sides of the transfer material, that is, one side of each of two transfer materials, or both the front and back sides of the same transfer material, in a single copying operation. In the copying machine 1 configured to be able to select copying modes separately, as shown in FIG. It has a document placement area for two sides, and has a structure with a center reference position X that aligns the center of the two screens, and when copying,
The position of the movable scanning optical system 6 is detected by an appropriate detection means installed inside the copying machine 1, and the movement sequence of the movable scanning optical system 6 is controlled by a control device such as a microcomputer. As shown in (b), the original of the first screen A is placed by the moving scanning optical system 6 from the optical system scanning start position a set a predetermined distance further upstream of the first screen A from the center reference position X. Exposure optical scanning is performed to a position a' downstream of the area plus a predetermined distance, and the first screen A is
After completing the exposure optical scan, the optical system 6 is moved back to the position a, and from there it is moved forward again to perform the exposure optical scan from the document placement area of the second screen B plus a predetermined distance downstream to position b'. After the exposure optical scanning of the second screen B is completed, scanning is performed by the optical system 6 so that the optical system 6 is moved back again to return to the above-mentioned position a. Or, see Figure 4 (/
As shown in →, the first screen A from position a to position a'
After completing the exposure optical scanning, move the optical system 6 to the center reference position
Scanning by the optical system 6 is performed so that the optical system 6 moves backward to a position set a predetermined distance upstream, moves forward again from there, performs optical exposure scanning of the second screen B to position b', and then returns to position a again. It is carried out.

(C) Problems to be Solved by the Invention By the way, in the scanning method shown in FIG.
The distance from position a to the position corresponding to position H in FIG. 4 is too long, and the distance from position b' to position a can only be used to return the exposure scanning optical system 6. Furthermore, in the scanning method shown in FIG. The exposure scanning optical system 6 must be stopped before the exposure scanning optical system 6 is moved back to the position, and the process of retreating from the position b' to the position a is simply a process of returning the exposure scanning optical system 6, as in the case of FIG. 3(b). Both of the scanning methods shown in FIG. 3(B) have many inconveniences in terms of process, such as being usable only for copying, and as a result, the time required for copying twice is increased.

In addition, in recent years, in copying machines, in order to prevent the fogging phenomenon in copies caused by the high density of the background of the original, such as when the original is colored or made of poor quality paper such as newspaper, etc.
Some machines have been developed that are equipped with an automatic exposure adjustment mechanism inside the machine. Before copying, such copying machines first measure the density information of the original, automatically adjust the exposure based on the results, and then start copying. In order to obtain the object, exposure optical scanning of the original is started, but as shown in Fig. 4 (b),
In the scanning method shown in Figure 3 (b) and in order to perform the automatic exposure adjustment as described above prior to copying, the first screen A of the original is usually scanned in the same scanning process as shown in Figure 3 (b) and
Therefore, the density information of the second screen B must be measured, which has the disadvantage that the time required for the second copy becomes longer and longer.

Furthermore, when measuring the density of a document in the same process as the scanning process as described above, automatic exposure adjustment is generally performed based on the average density value of the first screen A and the second side B. If the respective density values of the two screens B are significantly different, there is a problem in that a satisfactory copy cannot be obtained despite exposure adjustment.

(b) Means for Solving the Problem The present invention aims to solve the above-mentioned problems by moving the document surface of two screens set in the stationary document setting section from the first screen toward the second screen. The first optical system scan start position is set a predetermined distance upstream from the center reference position on the stationary original setting section for aligning the centers of the two screens, when viewed in the scanning direction of the movable scanning optical system that performs exposure optical scanning with the , a second optical system scanning start position is set upstream of the first screen and a predetermined distance further from the center reference position, and the second optical system is exposed to optical scanning of the second screen from the first optical system scanning start position. After the exposure optical scanning of the second screen is completed, the scanning optical system is moved back to the second optical system scanning start position, and then the exposure optical scanning of the first screen is performed from the second optical system scanning starting position. The image forming apparatus is characterized in that the movable scanning optical system in the image forming apparatus scans so that after the exposure optical scanning of the first screen is completed, the scanning optical system is moved back and returned to the first optical system scanning start position at tX. .

(E) Effect By employing the above means, when a copying command is issued, the movable scanning optical system, which was at the first optical system scanning start position,
Prior to copying, the second screen is first scanned to measure density information on the second screen, and then the first optical system is returned to the scanning start position to proceed to the copying process. When entering the copying process, first, the exposure optical scanning of the second screen is performed from the first optical system scanning start position to copy the second screen, and after completion of the exposure optical scanning, the second optical system is retreated to the second optical system scanning start position. In the backward stroke, the density information of the first screen to be copied next is also measured, and during this time, the transfer material for the first screen is supplied inside the copying machine. Next, exposure optical scanning of the first screen is performed from the second optical system scanning start position,
After that, the moving scanning optical system moves to the first optical system scanning position tx
be returned.

(F) Embodiments Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.

The moving scanning optical system 11 of the copying machine is, as shown in FIG.
Main moving scanning optical system 15 including a light source 12 and a first reflecting mirror 13, a second reflecting mirror 16 and a third reflecting mirror 17
and a sub-moving scanning optical system 19 that moves at 1/2 the moving speed of the main moving scanning optical system 15,
The main moving scanning optical system 15 and the sub moving scanning optical system 19
The document setting area is guided by a guide bar 20 and a galley rail 21, and has document setting areas for two screens, a first screen A and a second screen B, as shown in FIG. 1(a). The first screen A and the second screen B set on the set section 22 are moved along a stationary document setting section 22 provided with a center reference position X for aligning the centers of the two screens while optically scanning the exposure. It is configured. An optically detected member 23, such as a shielding plate, is installed in the main moving scanning optical system 15 at a position that coincides with the axis of the light source 12, and is movable on an appropriate fixed part inside the copying machine. In order to detect the detected member 23, for example, optical detection means s, s2. s3. s4 is provided.

Then, the detection means S2 detects the stationary document setting section 2.
The detection means S4 is provided at a position corresponding to the first optical system scanning start position shown in FIG. The detection means S is provided at a position corresponding to position b' in FIG.
l is provided at a position corresponding to the second optical system scanning start position a shown in FIG. Figure 1 (
(b) The main moving scanning optical system 1 is detected by each of the detection means S, ~S4 provided at a position corresponding to position a'.
By detecting the detected member 23 of No. 5, the main moving scanning optical system 15 of the moving scanning optical system 11 first issues a copying command under the control of a control device such as a microcomputer built into the copying machine. From the position in Figure 1 (b) to position b
', measure the density information of the second screen B, adjust the exposure corresponding to the second screen, and then move to position b-4 position b' as shown in FIG. 1(b). The second screen B is first copied, and then the first screen A is copied by moving from position a to position a' to position A.

Then, in the backward movement from position b' to position a,
In the subsequent process from position a to position a', the density information of the first screen A to be copied is measured in advance, and the exposure adjustment corresponding to the first screen A is performed, and during this time, the next copy is made inside the copying machine. In preparation for the first screen A to be displayed, feeding of transfer material, setting of the image forming section, etc. are performed.

In the above embodiment, four detection means are provided, but for example, the detection means S corresponding to the above position
It is also possible to provide only one and control the moving scanning optical system 11 in the same process as described above according to the timing set in advance by a microcomputer or the like.

(g) As described in detail, according to the present invention, the surface of the document set in the stationary document setting section 22 for two screens is exposed and optically scanned from the first screen A toward the second screen B. When viewed in the scanning direction of the moving scanning optical system 11, the first optical system scanning start position is set a predetermined distance α upstream from the center reference position Further, a second optical system scanning start position a is set upstream of the first screen A and a predetermined distance α from the center reference position X, and the second screen B is exposed optically scanned by the scanning optical system 11 from the above position. After completing the exposure optical scanning of the second screen, the scanning optical system 11 is moved back to the above position a, and then the exposure optical scanning of the first screen A is performed from the position a, and the exposure optical scanning of the first screen A is performed. The movable scanning optical system 11 in the image forming apparatus is configured to scan in such a way that the scanning optical system 11 is moved back and returned to the above-mentioned position after the scanning is completed, so that the scanning optical system 11 is moved backward until it returns to the position a after the copying of the second screen B is completed. The process of can be used to measure the density information of the first screen A and adjust the exposure, and therefore,
Measurement of density information and exposure adjustment of the original document prior to copying only need to be performed for the second screen, which not only significantly reduces the time required for exposure adjustment, but also for the second screen B and the first screen A. Even if there is a significant density difference between the images, the quality of the copy can be improved by responding to the difference individually.Also, since the journey to return to the above position a is relatively long, use this time to copy the subsequent first screen A. The internal equipment of the subject machine can be prepared effectively and with sufficient margin, and the time required for copying in this type of mode can be greatly reduced.

Furthermore, when the scanning method of the present invention is applied to an upward copying method in which a document such as a bound book is set facing upward in a document setting section in an open state and optical scanning is performed from above, it is possible to Due to the synergistic effect of the good engineering operability and the above-described effects of the present invention, it is possible to further greatly improve the copying performance of the copying machine.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a scanning method according to the present invention, FIG. 2 is a perspective view showing an example of a scanning optical system applicable to the present invention, and FIG. 3 is a schematic side sectional view of a general image forming apparatus. FIG. 4 is an explanatory diagram showing a conventional scanning method. DESCRIPTION OF SYMBOLS 15... Moving scanning optical system, 22... Stationary document setting part, A... First screen, B... Second screen, X... Center reference position, α... (deviated) ) predetermined distance, b...first optical system scanning start position
, a... Second optical system scanning start position.

Claims (1)

[Claims] (1) A stationary original setting area that has an original setting area for two screens, a first screen and a second screen, and a center reference position that aligns the center of the two screens, and a stationary original setting area that moves along the stationary original setting area. In the image forming apparatus, the image forming apparatus includes a moving scanning optical system that optically scans the surface of the original set in the original setting section from the first screen toward the second screen, when viewed from the scanning direction of the moving scanning optical system. , a first optical system scanning start position is set a predetermined distance upstream from the center reference position, and a second optical system scan start position is set a first screen distance and further a predetermined distance upstream from the center reference position, The movable scanning optical system performs an exposure optical scan of the second screen from the first optical system scan start position, and after completing the exposure optical scan of the second screen, the scanning optical system is retreated to the second optical system scan start position. Then, an exposure optical scan of the first screen is performed from the second optical system scan start position, and after the exposure optical scan of the first screen is completed, the scanning optical system is retreated and returned to the first optical system scan start position. Then, images corresponding to the images of the originals set on the first screen and the second screen are formed on different surfaces of the transfer material, that is, on both sides of the same transfer material or on one side of each of the two transfer materials. A scanning method of a moving scanning optical system in an image forming apparatus characterized by: