JPS6356645A - Original information detecting device for copying machine - Google Patents

Abstract

PURPOSE:To eliminate variation in light distribution characteristics for copy exposure by detecting optical variation of a reflected beam used to decide the size of an original and image density by an optical sensor which extends from outside an exposure lamp. CONSTITUTION:A reflecting plate 6 which has such an opening part 6a that part of a light beam projected with the exposure lamp 3 is projected on a photosensitive drum through the original 2 and part of a light beam 4 is projected toward an optical fiber 7 as the optical sensor through the original is arranged at the peripheral part of the exposure lamp 3. The fiber 7 consists of fibers 7a-7c, the fibers 7a and 7b are for original size detection, and the fiber 7c is for original density and extends slantingly from through holes 8a and 8b of a reflecting frame 8. Then the width of the original 2 is detected by the preliminary scanning of a scanner 13 with a detection signal from the fiber 7b and the width of the original 2 is detected with a detection signal from the fiber 7a. Consequently, variation in light distribution characteristics can be eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a copying machine, and more particularly, to
The present invention relates to a document information detection device for a copying machine that can detect sizes such as width and density of the document surface.

(Prior Art) A conventional copying machine employs the configuration shown in FIG. 5 to detect information on a document, that is, detect document size and density. In FIG. 5, contact glass 1
A light beam 4 emitted from an exposure lamp 3 disposed below the contact glass l is irradiated onto the original 2 placed on the original. A first opening portion 6a is formed so that a part of the light beam 4 emitted from the exposure lamp 3 can be irradiated onto a photosensitive drum (not shown) through the original through the mirror 5.
A reflecting plate 6 is provided with a second opening 6b so that a portion of the light beam 4 emitted from the exposure lamp 3 can be irradiated through the original in the direction of an optical fiber 7, which will be described later. The optical fiber 7 is held within a reflection frame 8, and upon receiving the reflected beam 9 after the light beam 4 irradiates the original 2, the original size and original density are detected by a conversion means (not shown). .

By the way, in the above-mentioned conventional apparatus, the second opening 6b is formed in the reflection plate 6 to convert a part of the light beam 4 emitted from the exposure lamp 3 into a light beam that is different from the light beam that irradiates the photoreceptor drum. It is meant to lead you to the path. Therefore, as shown in FIG. 6, when looking at the relationship between the exposure lamp in the document width direction and the illuminance, the illuminance decreases where the second opening 6b is located.

The above-mentioned phenomenon becomes larger as a plurality of optical sensors are provided to detect information on various documents, and as the numerical aperture of the reflector plate 6 increases accordingly. The light distribution characteristics as shown in the figure are distorted in a complicated manner, which causes a problem in that the latent image on the photoreceptor drum becomes abnormal.

(Objective) The present invention solves the above-mentioned problems of the prior art, and provides a copying method that allows good copies to be made without causing any change in the light distribution characteristics of the irradiated surface of the photoreceptor in the light beam emitted from the exposure lamp. The purpose of this invention is to provide a document information detection device for a machine.

(Structure) In order to achieve the above object, the present invention provides a plurality of optical sensors that are provided at predetermined positions in the width direction of the document and extend diagonally from the outside of the exposure lamp in order to detect reflected beams from the document. and driving means for scanning the optical sensor relative to the document surface, one of the optical sensors and the scanner detects the length of the document, and the other optical sensor detects the width of the document. The present invention is characterized in that it is configured to detect image information on the surface of the document as well as detect image information on the surface of the document.

Hereinafter, a detailed explanation will be given based on one embodiment of the present invention.

FIG. 1 is a side partial sectional view showing one embodiment of the present invention, and FIG.
The figure is a perspective view showing the main parts, and in the same figure, the same reference numerals are given to the members corresponding to those explained in FIG. 5.

In FIG. 1, an original 2 placed on a contact glass 1 is irradiated with a light beam 4 emitted from an exposure lamp 3 placed below the contact glass 1. The part has a tubular shape and can irradiate a part of the light beam emitted from the exposure lamp 3 through the mirror 5 to a photoreceptor drum (not shown) through the document, and a part of the light beam 4 can be irradiated to the photosensitive drum (not shown). 1 so that the light can be irradiated through the original in the direction of the optical fiber 7, which is a light sensor to be described later.
A reflection vi6 in which two openings 6a are formed is provided. The optical fiber 7 is held within a reflection frame 8, and the second
As shown in the figure, two through holes 8a and 8b formed in the earthen wall of the reflective frame 8 extend obliquely toward the contact glass 1. In this embodiment, the optical fiber 7
consists of three fiber bars 7a, 7b, and 7c, and the three fibers 7a, 7b, and 7c are arranged in the width direction of the original 2 (in the direction of the arrow), and are located in the front in FIG. The two fibers 7a and 7b are for detecting the original size, and the fiber 7c at the back is for detecting the density of the original. A photodiode 11 and an amplifier circuit 12 provided on the control board 1O are arranged at the end of each fiber 7a, 7b, 7c! The output of each amplifier circuit 12 is input to an A/D port of a CPU (not shown).

Further, as shown in FIG. 1, an exposure lamp 3, a mirror 5, a reflection plate 6, an optical fiber 7, and a reflection frame 8 are mounted on a scanner 13. This scanner 13 is scanned and guided by a guide shaft 14, and a drive belt 17 is wound around a pulley 16 fixed to one end of an output shaft 15a of a drive motor 15.
It is stuck to a part of. Output shaft 1 of the drive motor 15
An encoder 18 is fixed to the other end of 5a, and a phototransistor 19 and a light emitting diode 20 are arranged opposite to this encoder 18.

Next, the operation of the above-described embodiment will be explained.

That is, the document size is detected by preliminary scanning by the scanner 13 prior to the start of the copying operation. When the scanner 13 performs exposure scanning at a predetermined speed from the home position C, the scanner 13 returns to the home position C, and the detection signal from the optical fiber 7 detects the amount of movement from the return position 8 and detects the original. It is used to determine the length and width, and is also used to determine the original 115tH degree. The range of reflected light that can be received is regulated by circuits such as the photodiode 11 and the amplifier circuit 12 connected to each fiber 7a, 7b, and 7c.
When the amount of reflected light is greater than a predetermined reference amount of light, the outputs of the fibers 7a, 7b, and 7c are at a high level in an analog amount, and when the amount is less, they are at a low level. Specifically, when the amount of reflected beam 9 from the document 2 is large, the level is high, and when there is little or no amount, the level is low.

Further, output pulses accompanying the rotation of the encoder 18 are input to an internal circuit of the control board 10 and are counted as pulses.

Then, compare and measure the signal when the output of the central fiber 7b changes with the above-mentioned pulse count number, and measure the amount of movement from the return position A by scanning with the scanner 13. Convert to original length.

In addition, the fiber 7a is attached as shown in Figure 3(a) depending on the document size.
The detection output shown in is obtained.

For example, the original 2 is set on the contact glass 1 in A4 size horizontally. When the start button is pressed, the scanner 13 starts detection from the return position A, which is opposite from the document setting reference position B. From this return position A, the scanner 13 scans by the drive motor 15, and the optical fiber 7 is placed directly under the contact glass 1. From the time of movement, each fiber bar 7a, 7b, 7c starts receiving the reflected beam 9. As this start signal, the pulse count from the encoder 1 may be received.The output of the reflected beam 9 at this time is transmitted to the CPU via the amplifier circuit 12.
For example, read from the A/D boat of encoder 1.
The output of the reflected beam 9 from the original 2 is sampled at a pulse interval of 8, and the previous signal data and the next signal data are compared. If the signal data is several volts higher than the previous signal, it indicates that the original is present. Based on the pulse count of the encoder 18, the size is determined as shown in FIG. 3 (al).

In response to the document presence signal described above, the fiber 70 starts receiving light as shown in the timing chart of FIG. 4, and the signal from the amplifier circuit 12 is read by the A/D board of the CPU, and data sampling is performed based on the pulse interval. The signal data of the previous data is compared with the next data, and only the data with the larger value is stored in the register. After the scanner 13 has scanned a certain distance, the reading is finished,
Image density is detected based on the data output value at that time,
Set the concentration conditions. When the scanner 13 moves to the home position C, the copy exposure operation is started.

The output of the document size and horizontal or vertical setting state detected as described above is used together with the operation variable magnification mode to select the optimum paper, and the output of image density detection is used to set the developing bias condition.

The general operation process is that when the automatic document detection switch or the automatic density detection switch is turned on, the scanner 13
moves from home position C to return position A. After setting the document 2, when the start button is turned on, preliminary scanning for detecting the document size and document image density described above is started, and scanning is performed to the home position C.

During this time, each of the above-mentioned detections is performed, and when the scanner 13 reaches the home position C, copy exposure is started.

(Effects) As explained above, the present invention detects optical changes in a reflected beam used to determine the size of an original and image density using an optical sensor extending obliquely from the outside of an exposure lamp. Provides a document information detection device for a copying machine that eliminates the need to provide an aperture for an optical sensor in the exposure lamp as in conventional methods for detection, does not change the light distribution characteristics for copy exposure, and improves copy quality. can.

[Brief explanation of the drawing]

1 to 4 are diagrams for explaining one embodiment of the present invention, in which FIG. 1 is a partially sectional side view, FIG. 2 is a perspective view of main parts, and FIG. 3(a), Figure 3(b) is a diagram showing the relationship between document size and optical fiber, Figure 4 is a timing chart for starting optical fiber detection, Figure 5 is a partial cross-sectional side view of the conventional example, and Figure 6 is a diagram showing the light distribution characteristics. FIG. 2... Original, 3... Exposure lamp, 7.7a, 7b. 7C... Optical sensor, 15, 16, 17... Drive means. Procedural amendment (voluntary) Δ month/7, 1985

Claims (1)

[Claims] A plurality of optical sensors are installed at predetermined positions in the width direction of the document and extend diagonally from the outside of the exposure lamp in order to detect the reflected beam from the document, and these optical sensors are scanned relative to the document surface. drive means for detecting the length of the document using one of the optical sensors and the scanner, and detecting the width of the document and image information on the surface of the document using the other optical sensor. A document information detection device for a copying machine, characterized in that it is configured as follows.