JPS59123835A - Copying device - Google Patents

Abstract

PURPOSE:To detect the position of an original and density of an original background by detecting reflectance of the inside face of an original pressing plate, the original background, and an original character information part and comparing one with another. CONSTITUTION:A photodetector 9 receives light reflected from an original 0 placed on a moving platen 1 and illuminated with a lamp 10 to detect reflectance. This lamp for measuring the reflectance may be installed separately from an illumination lamp 10 for projecting the original image on a drum 11. An inside face of an original pressing plate 2 has been formed of a material as high in quality as Kent paper, so its reflectance is higher than that of the background of the original 0. The position of the original 0 is detected from their differences. The original density is also detected from the reflectances of an original character information part or the original background part, and the inside face of the plate 2, and copying conditions are adjusted so as to form the optimum density.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention also relates to a copying apparatus having an information reading device that detects size, controls density, and selects copy paper.

Conventionally, in copying machines, the density of a document has been detected by a method in which a light emitter and a light receiver are provided near the document, or a surface potential proportional to the amount of light reflected from the document is detected using an electrometer in a VC near the photoreceptor. Methods of measuring this are known.

In addition, as a means of detecting the position, size, or presence or absence of a document, a light emitter and a light receiver are installed together, so that the light traveling from the light emitter is blocked by the document (4-). does not reach / reaches O
N10FF-like measures are being taken.

For the former density detection method, Japanese Patent Application Laid-Open No. 367-2J discloses a method in which a light projector and a light receiver are integrated to scan the document surface before the latent image forming process and optically read the density. As a known example of principle, JP-A-4TG-3G7
In the publication No. 2002/1999, a switching mirror is provided in the middle of the imaging lens photoreceptor to read the density of the original. Further, in Japanese Patent Application Laid-Open No. 70727θ, a light receiver is provided in an aperture mask near the drum to read the original density.

On the other hand, regarding the latter method of reading the document position, Japanese Patent Application Laid-open No.
5-6-//4'? ．． ! As disclosed in Japanese Patent No. 3, there is a method in which a colored member is provided on a document holding plate and the boundary with the document is identified by a color sensor. Furthermore, as a method for detecting the presence or absence of a document, a method disclosed in Japanese Patent Application Laid-open No. 37-76777 involves processing a document table glass into a tipper shape and projecting light from a thick end surface using a projector. , the light that reaches the other end surface after being repeatedly totally reflected inside the tipper-shaped platen glass is captured by a light receiver. In this case, the presence or absence of a document is determined based on whether or not light enters the light receiver.

As described above, there are different methods for detecting the density of a document depending on how it is installed in the apparatus, but with the disclosed technology, it is unclear how to detect the document position and size. On the other hand, concentration detection is unknown with the technology disclosed for the detection of manuscript position machimei is.

In any of the known examples, in order to add other functions, it is not possible to detect the document position, size, etc. at the same time as density detection unless functional elements and structures suitable for the purpose are added separately.

However, Tokukai Akira! ;A-39! ;! In the '1 publication, a means for detecting the document position and density is proposed.

In the case of this proposal, the spectral characteristics of the photoreceptor and document holding cover are set to the same wavelength range, and the spectral wavelength range of the photoreceptor is separated from the wavelength range, and when there is a document on the document table, Since the reflected light from the original is flat in terms of wavelength, the reflected light is detected by a light receiver. If there is no document, the direct reflected light from the document holding cover will be directed to the receiver, but as mentioned above, the spectral reflection characteristics of the document holding cover are different from those of the receiver, The reflected light from the document holding cover is not detected. In this way,
The presence or absence of a document is determined by whether or not reflected light is detected by the light receiver.

In this method, if the background of the document is white (spectrally flat), the reflected light will be detected by the light receiver. However, if the original has a color background, light is absorbed depending on the color characteristics, and the reflected light from the original cannot be detected depending on the spectral sensitivity range of the light receiver. There is a drawback that if reflected light cannot be detected, the presence or absence of a document cannot be detected.

The present invention has been made in view of the above-mentioned points, and an object thereof is to provide information on the density information of the original, the position and size of the original, and the information on the original by using a set of a projector and a light receiver or by using a single light receiver. It is an object of the present invention to provide a copying machine equipped with an information reading device that is simple in configuration, has high reading accuracy, and is inexpensive, which reads presence/absence.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

FIG. 1 is a schematic explanatory diagram of a copying apparatus according to an embodiment of the present invention.

As shown in Figure 1, the movable document table glass/
An original θ containing information to be read is placed on top of the original θ, and an original holding plate 2 for pressing the original θ is placed above it. A mirror 3 is disposed at a suitable position in the copying machine at the lower left side of the original platen glass.
Mirror names S are arranged on the left side of , and these mirrors <4.5 are orthogonal to each other. Further, a mirror 7 is also disposed at a suitable position in the copying device on the lower right side of the document platen glass /, and an imaging lens 6 is disposed between the mirror S and the mirror 7. .

Further, there is a light emitter immediately below the right side of the document platen glass / that emits light onto the original θ and the original holding plate 2, and a light receiver that receives the light emitted from the original θ and the light reflected from the original holding plate 3. The receptacles are respectively disposed at suitable positions within the copying machine.

Note that the original illumination lamp/θ is the original platen glass/and the mirror 3.
It is placed between the glass / and the manuscript holding plate! When scanning the document by moving integrally in the direction of the arrow, the reflected light from the document θ that receives the illumination light from the document illumination lamp/θ is reflected by mirror 3, mirror ty:, s, lens 6, and mirror 7. The light is projected onto the surface of the photosensitive drum // through a path indicated by a dashed line through the optical system. /ku/3
are a paper feed roller and a paper ejection roller, respectively, which are components of a normal copying machine.

In the embodiment of the present invention having such a configuration, first, the projector and the document holding plate are moved parallel to the document platen glass with respect to the receiver to scan the document, and then the document platen glass is moved by the projector at an angle of 8 degrees. / to illuminate the original surface and the original holding plate surface, and the reflected light is received by the light receiver. When light is emitted from the emitter g and received by the receiver 2, the lines in FIG. As shown in the figure, it is possible to create an output difference between the density of the original's base (the intensity of light reflected from the base) and the intensity of the reflected light from the surface of the original holding plate. The spectral reflection characteristics of the light receiver 20 and the spectral characteristics of the light receiver 20 are arranged to be in approximately the same region. That is, the spectral characteristics of the light receiver are set so as to include at least a region of spectral reflection characteristics including the density of various original document bases. This is because, in order to detect the position of the original or the presence or absence of the original, at least the reflected light from the base of each type of original needs to be output to the light receiver. Here, a represents the spectral characteristics of the light receiver 2 (including the spectral characteristics of the emitter), 5 to g represent the spectral reflection characteristics of the base of various originals, b is white, c is yellow, d is magenta, e represents cyan, f represents blue, and g represents brown, respectively, and h represents spectral reflection characteristics related to information on the original. Furthermore, in the present invention, as shown in the diagram showing the output characteristics of the light receiver in FIG. It is being done.

This means that, for example, the reflectance of the base of a general document is wavelength 3! ;O
At ra, it is around 2 notches for a 5° incidence, but on the other hand,
If the same characteristics as Kent paper are used for the surface of the document holding plate, the paper will be around 2 das under the same conditions. The position of the original or the presence or absence of the original can be detected based on the difference in reflectance between the two.
II indicates the intensity of reflected light from the document base, and "B"
indicates the intensity of reflected light from the flesh surface of the original presser plate a Cj
′ indicates the intensity of reflected light from image information in the document, such as characters, numbers, pictures, etc. In this way, the light receiver generates an output difference among the three, detects the position or presence of the original by the output difference between A and B, and detects the output difference between A and C (or the difference between A and the standard original from the base The appropriate exposure amount for copying can be detected based on the output difference with the reflection intensity). FIG. 9, which shows the document size and the scanning direction of the light receiver and light emitter, shows the sizes of various kinds of documents, and also shows that the document moves from the X to the Y direction with respect to the light emitter and light receiver. , indicates that the original background density is detected simultaneously with the position of the original or the presence or absence of the original.

The first flowchart shows that the two detection outputs detected in this way are used to control the 1d-≠-Kikobee density on the one hand, and to control the size selection of the copy paper on the other hand. Figure 5. It goes without saying that these control methods can be achieved using conventional techniques. For example, as shown in FIG. The signal output from the sensor/5 that detects the output/output difference detection circuit/B inputs the detection signal detected from the magnitude of the output difference to the concentration/position information comparison processing circuit/7. This detection signal not only detects the position, but also detects concentration information from the magnitude of the output difference.This signal is input to the information comparison processing circuit 77' in advance.
Based on the comparison result, a density signal /g and a position signal /9 whose density and position have been detected are output from the information comparison processing circuit /7.

This concentration signal/g is passed through the control circuit 2θ to the lamp voltage,
2 and development bias 2. ．． 2 and the position signal /9 is used to control the size of the document via the control circuit, 23. In this way, the density information of the original, the position of the original, the presence or absence of the original, and the size of the original can be read. Further, it goes without saying that when the document is fixed, the same effect and result can be obtained even if both the light projector and the light receiver are moved simultaneously in the X to Y direction.

FIG. 6 shows a schematic explanatory diagram of another embodiment according to the present invention, in which a pinhole or a sag-like hole is provided in the mirror 3, and a light receiving device is placed immediately behind the hole. In addition, the arrangement of the photoreceiver/sol can be freely selected as long as it can measure light within a range that prevents the imaging light flux.
The operation of the device shown in the figure is almost the same as that shown in FIG. 1, except that the light receiver 2 directly receives the light illuminated by an illumination lamp /θ instead of a projector.

As explained above, according to the present invention, information obtained from a simple configuration is electrically processed, and the obtained density information is used to control the light amount of the illumination system or the developing bias, thereby ensuring that clean copies are always made. is obtained. In addition, it is possible to provide an easy-to-use copying device that automatically selects the copy paper based on the information on the document position and size, and can reliably match the original size and copy paper size. effective.

[Brief explanation of drawings]

FIG. 1 is a schematic explanatory diagram of a copying apparatus according to an embodiment of the present invention, and FIG. 2 is a diagram showing the spectral characteristics of a light receiver and the spectral reflection characteristics of a document base, a document holding plate, and various document bases. Figure 3 is a diagram showing the output characteristics of the receiver, Figure 5 is a diagram showing the document size and the scanning direction of the receiver and emitter.
The figure is a flowchart of signal processing according to one embodiment of the present invention, and FIG. 6 is a schematic explanatory diagram of another embodiment according to the present invention. θ...Original /...Original table glass! Document holding plate 3, G, 5.7...Mirror B...Imaging lens...Emitter...Receiver /θ...Original illumination lamp//...
Photosensitive drum/Event...Paper feed roller/3 Paper ejection roller/G Pulse generation circuit/J・Sensor/Otsu・
・Output/output difference detection circuit/7 Information comparison processing circuit/and...Concentration signal/9・Position signal Go to 2, 23 Control circuit patent applicant Canon Corporation

Claims (1)

[Claims] A copying device that reads the density information and position of a copied document by receiving reflected light from the base of the document and the inner surface of the document presser, the copying device reads the density information and position of the document to be copied by receiving reflected light from the base of the document and the inner surface of the document presser. The characteristics are different, and the spectral sensitivity characteristics of the light receiver that receives the reflected light overlap at least the spectral reflection characteristics of the base of the original, and the intensity of the reflected light of the base of the original is different from that of the original. A copying apparatus comprising a detection device for reading density information and position of a document to be copied by increasing the intensity of reflected light from a presser plate surface.