JPS63313145A - Original size detecting device - Google Patents

Abstract

PURPOSE:To eliminate the effect of disturbance light and to accurately detect the original size by extracting the data of the original size based on time series data detected by an original detecting sensor till an original cover is completely closed. CONSTITUTION:A sensor unit 26 having a structure where a light emitting element and a light receiving element are adjacent is arranged corresponding to the position equal to the difference of the original of a fixed form size which is the most approximate. The unit 26 repeatedly outputs the detection data of the original size in time series in a state obtained before the original cover 13 is completely closed. The time series data is sequentially compared, and the effect of the disturbance light is eliminated and the accurate detection data of the original size can be obtained by extracting the smallest data in the time series data at the time when the original cover 13 is completely closed.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a document size detection device, and more particularly, to a document size detection device that performs a document size detection operation during an operation of closing a document holder.

<Prior Art> Many copiers, facsimile machines, and the like have been provided with a document size detection function in order to be able to set documents of various sizes.

To explain the general configuration of such a document size detection device, a plurality of sensors are provided in a preset positional relationship at a predetermined position below a contact glass for setting a document, and when the document holder is open. (More precisely, in a state where it is not completely closed), the document size is detected based on the amount of light received by a sensor consisting of a light receiving element or the like.

To explain in more detail, the above-mentioned sensors are roughly classified into transmissive type and reflective type. Among these, in the transmission type, the light is not guided to the light receiving element where the document is present, and the document size is detected based on the light being guided when the document is not present. In the reflective type, the document size is detected based on the fact that light is guided to the light-receiving element when an original is present, and light is not guided to the light-receiving element when no original is present.

Therefore, it is possible to identify which standard size the document corresponds to based on which light receiving element outputs a signal indicating that a predetermined amount of light or more has been received.

By using a switch to detect the timing before the document holder is completely closed, the document size detection operation described above is performed, thereby eliminating the influence of ambient light that enters through the contact glass, and making it possible to detect the document size quite accurately. A method to do this has also been proposed (Japanese Unexamined Patent Application Publication No. 1981-1999)
Publication No. 151523, and JP-A-61-193141
(see publication).

<Problems to be Solved by the Invention> In the document size detection device having the above configuration, in order to completely eliminate the influence of ambient light, it is difficult to accurately detect the state in which the document holder is closed to a predetermined position. Therefore, it is essential to increase the positional accuracy when installing the switch.Moreover, the positional accuracy must be set by taking into account variations in sensitivity of each light receiving element, etc. There is a problem of poor sex.

To explain in more detail, the mounting position of the above switch is not sufficient to simply prevent ambient light from being guided to the light receiving element, but it is also necessary to prevent the light reflected from the document holder, which is difficult to distinguish from light reflected from the document. Light must be prevented from being guided to the light receiving element. Therefore, the position of the document holder to be detected by the above switch needs to be a very limited position where neither ambient light nor reflected light from the document holder will affect the light receiving element. Moreover, since the switch mentioned above is usually installed near the center of rotation of the document holder, the installation of the switch may be affected by positional errors and variations in the switch itself.
The distance between the tip of the document holder and the contact glass will vary greatly. As a result, there is a problem in that the influence of ambient light or the influence of reflected light from the document holder occurs at the timing when the document size is detected, resulting in an incorrect document size being detected.

Since the erroneously detected document size is larger than the actual document size, if the paper size is automatically selected based on the document size, the image formation magnification is automatically selected. In some cases, a paper size larger than necessary may be used, or a magnification smaller than necessary may be selected.

<Object of the invention> This invention has been made in view of the above problems.
It is an object of the present invention to provide a document size detection device that can improve document size detection accuracy and simplify the configuration and assembly work.

Means for Solving the Problems> In order to achieve the above object, the document size detection device of the present invention detects the size of the document every time the output signal from the document detection sensor changes within a predetermined range until the document holder is closed. a signal holding means for capturing output signals and holding them in time series; a data extraction means for extracting data unaffected by noise from each time series data held in the signal holding means; and a data extraction means. The document size signal generation means receives data outputted from the document size detection signal and generates a document size detection signal.

However, it is preferable that the document detection sensor has a light emitting element and a light receiving element in close proximity to each other.

Function> With the document size detection device of the invention described above, when a document is set on the contact glass and the entire surface of the document is exposed to light to form an image corresponding to the document image, the document size detecting device of the invention can detect the size of the document until the document holder is closed. Each time the output signal from the document detection sensor changes within a predetermined range, the output signal is captured and the captured signal is held in time series by the signal holding means. Then, based on each time series data held in the signal holding means, the data extracting means can extract data that is not affected by noise. Therefore, the document size detection signal can be generated by the document size signal generating device using human power from the data output from the extracting device. .

If the density detection sensor is one that has a light-emitting element and a light-receiving element in close proximity to each other, the amount of light reflected is determined based on the output light amount of the corresponding light-emitting element and the presence or absence of a document. Light or scattered light can be received by each light receiving element.

<Example> Hereinafter, embodiments will be described in detail with reference to the accompanying drawings showing examples.

FIG. 6 is a perspective view of the main parts showing the general structure of the copying machine, in which a contact glass (11
), an operation panel (12) is provided on the front side of the top surface, and a document holder (13) is provided on the rear side of the top surface so as to be movable up and down. Then, the contact glass (11) and the operation panel (
A switch (14) is provided at a predetermined position between the original document holder (12) and the original document holder (13) to detect a completely closed state. Specifically, the switch (14) is a reed switch, and is driven by a magnet (15) provided at a predetermined position on the document holder (13).

FIG. 5 is a schematic perspective view showing the configuration of an optical section for illuminating the original set on the contact glass (11), one end of which is inserted through the guide rod (21), and the other end of which is inserted into the guide rail (22). ) and a second movable frame (24) supported by the main body of the copying machine. A sensor frame (25) is connected at the ends and has a bendable central portion. A plurality of sensor units (2B) are mounted at predetermined positions on the upper surface of the sensor frame (25) by integrating a light emitting element and a light receiving element in close proximity to each other. In addition, (27) transmits driving force to both the above-mentioned moving frames (23) and (24), and is a first frame equipped with a light source (28), a curved reflector (29), and a first reflector (30). A drive wire that sets the moving speed of the moving frame (23) to twice the moving speed of the second moving frame (24) equipped with a pair of reflecting mirrors (31 and 32), and (33) is a driving wire that It is a motor pulley that applies a tensile force in the forward and reverse directions to the wire (27), (34) is a lead wire that runs along the outer surface of the sensor frame (25), and (35) is a lead wire that applies a tension force in the forward and reverse directions to the wire (27). It is a part that prevents damage.

Figures 3 and 4 are diagrams explaining the mounting position of the sensor unit (26), and each sensor unit) (28
) is made to correspond to the position corresponding to the difference between the documents of the most approximate standard size, and in the state before the document holder (13) is completely closed (see Figure 3), the influence of ambient light is , and the influence of reflected light from the document holder (13) can be completely eliminated, the sensor unit (26) corresponding to the area where the document (D) is located will direct the light from the light emitting element to the document (D). The light from the light emitting element is transmitted upward through the contact glass (11) to the sensor unit (26) corresponding to the area where the document (D) is not present, and the light is reflected and guided to the light receiving element. It is in a state where it is not guided to the element.

Therefore, if the influence of ambient light and the influence of reflected light from the document holder (13) can be completely eliminated as described above, each sensor unit (26 ) in the part corresponding to the manuscript (D
) can be detected. and,
Since the mounting position of the sensor unit (26) is set in advance as described above, it is possible to identify which standard size the document corresponds to.

FIG. 1 is a schematic block diagram showing the electrical configuration of the copying machine, in which the output signals from each sensor unit (26) are
Microcomputer (3) through converter (37)
8), and also supplies signals from the operation panel (12) and signals generated by the switch (14) to the microcomputer (38).

The output signal from the microcomputer (38) is supplied to an exposure distance control section (39) and a paper size selection section (40).

In addition, (36) is a memory, and each sensor unit (26)
) and converted by the A/D converter (87) are stored in time series. The microcomputer (38) mainly determines whether each piece of time-series data is composed of the same data or not. Specifically, the microcomputer (38) performs the determination and processing as shown in the flowchart shown in FIG. That's what I'm supposed to do.

The above flowchart will be explained in detail below.

When the power is turned on for the first time, the variable n is initialized to zero and the variable m is initialized to 1, and in step It is determined whether (14) is ON or not.

The document presser (13) is not completely closed 8 (including not only the fully open state but also the state in the middle of closing).
If it is determined that
The data obtained by converting into a digital value by the converter (37) is stored in the accumulator AC, and step
It is determined whether the variable n indicating the number of times of memory storage is zero or not, and if the variable n is zero, the contents of the accumulator AC are stored in the memory (36) in step ■, and the variable n is increased by 1 in step ■. let Furthermore, if it is determined in step (3) that the variable n is not zero,
In step ■, the contents of the (n-1)th memory and the contents of accumulator AC are compared, and if it is determined that they are not equal, the process of step ■ above is performed as is, and conversely, it is determined that they are equal. If so, the process ends immediately.

That is, by repeating the above-described determination and processing until the document presser (18) is completely closed, document size detection data as shown in the following table can be obtained.

Furthermore, if it is determined in the above step (2) that the document holder (13) is completely closed, in step (2), it is determined whether or not the variable n is zero;
If it is determined that it is zero, the process ends as is, but if it is determined that it is not zero, the Oth memory content is stored in the accumulator AC in step
Whether variable m and variable n are equal in step ■,
That is, it is determined whether there is one piece of captured data or a plurality of pieces of captured data, or whether the following determination and processing have been performed on all of the captured data.

If n+m is determined in the above step (3), it is determined in step [phase] whether or not the contents of the accumulator AC are larger than the contents of the m-th memory, and if it is determined that the contents are larger than the contents of the m-th memory, m in step ■
The contents of the th memory are stored in the accumulator AC, and in step @, the value of m is increased by 1, and the determination in step (2) is performed again. Conversely, if it is determined in the above step [phase] that the contents of the accumulator AC are not larger than the contents of the mfltth memory, the process of step @ is directly performed.

That is, by repeating these series of determinations and processes,
Among the data chronologically stored in the memory, the smallest data (data not affected by disturbance light) is stored in the accumulator AC.

On the other hand, if it is determined that the document size is nm in the above step Clear all memory contents from to nth and proceed to step ■
In n-5Q.

m-1, and the process ends.

In summary, the document detection signal output from each sensor unit (2B) is detected only when the output signal from the sensor unit (26) corresponding to a large document size is MSB and when a change occurs. Time series data can be generated and retained by storing it in memory.

Then, when the original presser foot (13) is completely closed,
By extracting the smallest data from the time-series data, it is possible to eliminate the influence of external light and the like and obtain accurate document size detection data.

Note that the present invention is not limited to the above-described embodiments; for example, the sensor unit may be provided in an immovable manner, or the data constituted by the output signals from the sensor unit may be arranged in reverse order. It is possible to make various other design changes without changing the gist of the invention.

<Effects of the Invention> As described above, the present invention performs the document detection operation using the light receiving element until the document holder is completely closed, and finally adjusts the document size based on the obtained document detection time series data. Since the document detection data that corresponds to the document size is extracted, the effect of special feature (a) is that the influence of scattered light, reflected light from the document holder, etc. can be eliminated, and the document size can be accurately detected.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the main parts of an embodiment of the document size detection device of the present invention, FIG. 2 is a flowchart explaining the document size detection operation, and FIG. 3 is a longitudinal sectional view showing the main parts of the copying machine. , FIG. 4 is a diagram explaining the positional relationship between the document size and the sensor unit, FIG. 5 is a perspective view showing the main parts of the optical system, and FIG. 6 is a perspective view showing the main parts of the copying machine.

Claims (1)

[Scope of Claims] 1. A document detection device having a document holder for fixing the document on a contact glass, and a document detection sensor provided below the contact glass corresponding to a plurality of standard sizes, A signal holding means captures the output signal from the document detection sensor every time the output signal changes within a predetermined range until the document holder is closed, and holds the output signal in chronological order; The present invention is characterized by comprising a data extraction means for extracting data not affected by noise from the series data, and an original size signal generation means for generating an original size detection signal by inputting the data output from the data extraction means. Document size detection device. 2. Claim 1 above, wherein the document detection sensor has a light emitting element and a light receiving element in close proximity to each other.
Document size detection device described in Section 2.