JPS61151559A - Forming device of image - Google Patents

Abstract

PURPOSE:To form always correct images even if the first page and the second page of an original are different in picture quality, by setting an optimum image forming condition to each page on the basis of an original density detection signal corresponding to two pages of the original which is obtained by one original scanning when the pages of the original are copied continuously. CONSTITUTION:In case of continuous page copying, a book 2' as the original placed on an original platen glass 1 is irradiated with the rays of light from a point A to a point C through a point B by one original scanning of a halogen lamp 3, and the reflected light from the book 2' is made incident on an optical sensor 13. The detection signals is inputted from the optical sensor 13 to a signal processing circuit 14 and is divided to an average original reflection density from the point A to the point B and that from the point B to the point C, and halogen lamp lighting voltages corresponding to them are determined. At the copying time, the halogen lamp 3 and an optical system consisting of optical path changing mirrors 4b-4e, etc. are operated automatically, and the lamp lighting voltage is changed and controlled by a DC controller 15 on the basis of average original reflection densities to control the exposure of the halogen lamp 3 to a correct value.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application)
[Related to an image forming apparatus that performs adjustment.]

(Prior Art) Generally, in this type of image forming apparatus, the density of the original is detected by a means for detecting the image state of the original, image forming conditions are determined based on the signal, and an image of a predetermined density is formed on a support material. . The image forming conditions include the voltage applied to the light source to brighten the original, the amount of exposure thereof, the amount of light reflected from the original that actually irradiates the photoreceptor, the developing bias voltage, and the stabilization of the charge on the photoreceptor. At least one of the above image forming conditions is controlled as necessary.

Recently, electrophotographic copying devices have been introduced that have an automatic density adjustment function and a continuous page copying function. This has a function that makes it possible to omit the work of replacing the book when copying the double-page spread of a book one negative at a time. In Mort', which combines such page continuous copying function and automatic density adjustment function, the following Ij7Lf14 detection methods are available: a) A method that detects the image condition of only a part of the original; b) A method that detects the image condition of the entire screen of the original. There is/a
In method b, only the image condition of the first negative page of the original is detected, and the image forming conditions for the second page are the same as for the negative page. The conditions are detected simultaneously and the image forming conditions are determined from the average value.

(Problem to be Solved by the Invention λ However, in the above-mentioned document detection method, if the negative value is a text document and the second negative value is a color document or a photo document, a large negative difference is caused for the internally placed document. Therefore, the present invention was made by paying attention to the above-mentioned conventional problem, and its purpose is to provide a negative-eye image and a second-eye image during continuous page copying. The purpose of this invention is to always obtain an appropriate image by automatically adjusting the density for each page even if the original is of different quality and has good image quality.

(Means for Solving the Problems) In order to achieve the above object, an image forming apparatus 1 according to the present invention
an M document density detection means for detecting the amount of reflected light corresponding to IS2 negative by scanning the document twice before the copying step, and generating a detection signal for pairing each page; The exposure rung lighting voltage is determined based on the detection signal output from the detection means.
and an image forming condition control stage for setting at least one of the image forming conditions such as the image bias voltage and the band width of the photoreceptor to an optimum value for each page of YA Kusunoki.

(Embodiment) Hereinafter, an embodiment of an image forming apparatus according to the present invention will be described based on the drawings.

FIG. 1 schematically shows an electrophotographic copying apparatus that utilizes the present invention, and the configuration thereof will be explained below.
2 is a document placed on the IJ7A Yuzu table glass 1; 3 is a Haloken lamp as an example of an exposure light source for exposing the yA document 2; 4b, 4c, 4d, and 4e are mirrors for changing the optical path. , four companies' imaging lenses, the halogen lamp 3 and mirrors 4b, 4c, and 4d are moved back and forth to the dotted line position in Figure 1 to obtain the original f? After scanning 42,
Move back to the original solid line position.

Reference numeral 5 denotes a photosensitive drum, which is rotatably supported in the direction of arrow A in FIG. A charger 9, a separation roller 10, and a cleaning device 11 are provided. In addition, a light source for pre-exposure, a light source for non-image area exposure, a flat layer device i1, etc. are arranged around the circumference of the photosensitive drum 5, but these are omitted for convenience of explanation.

12 is a transfer material.

Reference numeral 13 denotes an optical sensor such as a CCD, which is placed in a position that does not interfere with the image density incident on the imaging lens 4, and is used to detect the image density of the original. When illuminating while scanning, the reflected light from the source 2 enters the optical sensor 13, and the optical sensor 13 detects that the output falls (g is sent to the signal processing circuit 14 and processed there. After that, it is manually inputted to the DC controller 15.L) A lamp lighting voltage control signal is output from the C controller 15 to the CVR 16 in accordance with the relationship between the original reflective light cover and the rung stipple voltage shown in FIG. Here, the signal processing circuit 14, DC controller 15, and CVR 16 constitute an image forming condition control means 17. halogen rung 3
A type with a rating of 80V and 250W is used, and for a standard original, when the lighting voltage of the Haloken rung 3 is 65V, an appropriate image with good contrast and no capri is formed.

When detecting the image density of an original, the average original reflection IIk degree of a colored original or a photographic original is detected as a cylindrical value as well as that of a standard original. The lamp lighting voltage is determined from the relationship of one reflection.

Now, when performing continuous page copying, as shown in Figure 3,
A book 2', which is an M-sized yuzu, placed on the document table crow 1 is irradiated with light from A to B to C in one scan of the document by the halogen lamp 3, and the reflected light from the book 2' is detected by the optical sensor. 13. Then, the detection signal from the optical sensor 13 is input to the signal processing circuit 14, where the signal from point A to point B (-negative) is inputted to the signal processing circuit 14.
and the average document reflection density of the second page from point B to point Ct, and the Haloken lamp lighting voltage for the pair is determined according to FIG.

Next, during copying, the optical system t- includes a halogen lamp 3 and mirrors 4b, 4c, 4d + 4e for changing the optical path.
As shown in Figure 4, the LIC is actuated visually, based on the average JJA reflection density from point A to point B.
The controller 15 controls the lamp lighting ratio to adjust the exposure amount of the halogen lamp 3 to an appropriate value, and then the optical system moves from point A to point B1 to copy the first page of the book 2'. After that, the optical system returns to the point A position. After adjusting the exposure amount of the halogen lamp 3 to an appropriate value using the DC controller 15 based on the average original reflection density from point B to point C, the optical system starts moving forward for the second time and moves from point B to point C. The halogen lamp 3 is turned on until C to copy the second negative number of the book 2', and then the optical system returns from point C to point A. In this way, even if the image quality of the first and second pages of Book 2' is different,
- Appropriately change the lighting voltage when copying the first page and the lighting voltage when copying the second negative page! The halogen lamps 37 can be turned on under conditions such that contrast without capri can be obtained through adjustment.

In the above embodiment, the halogen lamp lighting voltage is controlled based on the detection signal from the optical sensor 13, but the invention is not limited to this. The developing bias voltage applied to the master imager 70 and the image sleeve 7a and the voltage on the photoreceptor may be controlled based on the signal, and the halogen lamp lighting voltage 1. The odor change control may be performed on all of the image bias pressure 2 and the potential of the photoreceptor 11 based on the detection signal from the sensor 13.

(Effects of the Invention) The 1lIli image forming device gt according to the present invention has the above-described configuration and operation, and when printing originals such as books, two originals obtained by - times of original set meals are obtained. flkK
By setting the optimal image format for each page based on the detection signal, it is possible to always capture an appropriate image even if the image quality of the first and second pages of the document is different. can.

[Brief explanation of the drawing]

The drawings show an embodiment of the image source type hx and apparatus according to the present invention, and FIG. 1 is a schematic side view of an electrophotographic copying apparatus equipped with an image forming apparatus according to the invention, and FIG. A graph showing the relationship between the rung lighting voltage and the average original reflection density according to the negative 2i? Figure 4 shows the operating state of the optical system during negative slow shooting of a book. It is four diagrams. 13... Optical sensor as 10 stages of Suzokusu manuscript detection 17...
・-1 image form M, control means Fig. 3, Fig. 4; = conflict hao? ／、＋、＊'T □ Hello Dōl lights out

Claims (1)

[Claims] Before the copying process, a document density detection means detects the amount of reflected light for two pages of the document by one scan of the document and generates a detection signal based on the density of each page; The exposure lamp lighting voltage is determined based on the detected signal.
An image forming apparatus comprising: image forming condition control means for setting at least one of image forming conditions such as a developing bias voltage and a charging potential of a photoreceptor to an optimum value for each page of a document.