JPH05241255A - Copying device - Google Patents

Abstract

PURPOSE:To prevent back light during scanning caused by the light emission of original detecting sensors and further, their erroneous detection by a scanner under the scanning. CONSTITUTION:While an illuminating lamp for irradiating an original is turned on, and a driving means for driving the scanner, is operated, that is, a carriage on which the scanner is mounted, is moved, the light emission of light emitting elements 14a and 15a is prohibited. On the other hand, it is detected that the original detecting sensors 14, 15 are in a state where a normal detecting action can not be taken, while the device is operated and an object (the carriage) disturbing the detection of original size passes between the original detecting sensors 14, 15 and a placed original.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copying apparatus in which an electrophotographic process is executed, and more particularly, to a copying apparatus characterized by controlling a document detecting means including a light emitting element and a light receiving element for detecting the size of a document. Regarding the device.

[0002]

2. Description of the Related Art In a copying machine, an "automatic paper selection" function for selecting a paper according to the size of an original and a copy magnification, and an "automatic automatic selection for selecting a copy magnification according to the size of an original and a designated paper size" In order to realize the "magnification selection" function, it is common to detect the size of the document on the document table (contact glass).

By the way, there are various methods for detecting the original size of a copying machine, but a method using an original detection sensor consisting of a light emitting element and a light receiving element fixed at a position below the contact glass that does not hinder the movement of the original scanning carriage. Is excellent in cost (performance), pre-scanning (press key)
It is often used because it is unnecessary (for example, Japanese Patent Laid-Open No. 62-6241).

In this case, it is necessary to keep the light-emitting element constantly lit so that the document size can be detected even when the document pressure plate which is openable and closable with respect to the contact glass is released. The element starts to emit light when the power switch of the copying machine is turned on.

The light emitting element and the light receiving element used here are positioned so as not to obstruct the movement of the original scanning carriage, and are placed at a distance of several tens to hundreds of millimeters from the original, so that the infrared region having a large light emission output is provided. Stuff used.

[0006]

However, the spectral sensitivity characteristic of the element used for photoelectric conversion of the original image is
For example, there is a relative sensitivity of about 0.2 to 0.45 with a peak of 1 for incident light of wavelength 900 nm (for example, pn
Photosensitive elements such as photodiodes and CCD image sensors).

For this reason, a fluorescent tube or a visible light LED which does not have infrared light in the emission spectrum in the first place, irrespective of the device using a halogen tube as a light source for reading an original,
In an apparatus using such a device, an infrared light cut filter, which brings about a large cost increase, is not generally placed in front of the photoelectric conversion element described above. There is a problem that the supporting member is reflected at an unexpected place and jumps into the optical path, which adversely affects the original reading signal (image signal).

Further, since the carriage moves between the light emitting element and the light receiving element and the original during the copying operation, if the carriage comes right above the light emitting element and the light receiving element, the light cannot be correctly received. Therefore, conventionally, there is a problem that the size of the new original cannot be correctly recognized when the original is replaced and the pressure plate is closed while the carriage is being driven (during the return operation).

According to the present invention, it is possible to prevent back light during scanning due to light emission of the document detecting sensor without using an infrared cut filter, a light shielding member, or the like, and to prevent erroneous detection of the document detecting sensor due to scanning during scanning. It is an object of the present invention to provide a copying apparatus that can prevent the above.

[0010]

The above-mentioned object is to provide an illuminating means for illuminating an original placed on an original table for a copying operation, a driving means for scanning the original, and a position corresponding to the original size. Light-emitting means which are respectively arranged, are turned on when the power switch is turned on, and emit light so as to face the placed document,
A copying machine having a plurality of light receiving means for respectively receiving reflected light from a document by light emission of a plurality of light emitting means, and an identification means for identifying a size of a placed document by a light receiving signal of the light receiving means, This is achieved by the first means having a control means for inhibiting light emission.

Further, the above-described object is to provide an illuminating means for illuminating an original placed on an original table for a copying operation, a driving means for scanning the original, and a power source which is arranged at a position corresponding to the original size. Light-emitting means which is turned on when the switch is turned on and emits light in opposition to the placed document, a plurality of light-receiving means for respectively receiving reflected light from the document due to light-emission of the plurality of light-emitting means, and light-receiving signals of the light-receiving means In a copying apparatus having an identification means for identifying the size of the placed document by
A state detecting means for detecting whether or not the original detecting means constituted by the light emitting means and the light receiving means is in a state in which normal detection operation is impossible, and a delay means for delaying the output of the original detecting means for a predetermined period. Is achieved by the second means.

[0012]

In the first means, the light emitting means (light emitting element) is operated while the illuminating means (illuminating lamp) for illuminating the original is lit and the drive means for driving the scanner is operating, that is, while the carriage carrying the scanner is moving. ) Is prohibited.

In the second means, while the apparatus is operating, the manuscript detecting means operates during a period in which an object (carriage) obstructing the detection of the manuscript size passes between the manuscript detecting means (manuscript detecting sensor) and the placed manuscript. Normal detection Detects the inoperable state.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a control block diagram of a main part of a copying apparatus according to the embodiment, in which 1 is a control unit including a CPU,
2 is a lamp control circuit for controlling the illumination lamp 3, 4 is a motor control circuit for controlling the motor 5 for driving a carriage,
6 is a carriage position detection circuit, 7 is a pressure plate opening / closing detection circuit,
Reference numeral 8 is a document size detection circuit, and 9 is a delay circuit.

FIG. 2 is a side view of the vicinity of the contact glass, in which 10 is a pressure plate, 11 is a contact glass on which a document shown by hatching is placed, and 12 and 13 are the shaft fulcrum side (back side) and the tip side (the back side) of the pressure plate 10. The lead sensor provided on the front side,
Pressure plate open / close detection sensor composed of photo sensor, etc., 1
Reference numerals 4 and 15 denote document detection sensors arranged at different positions below the contact glass 11, and each of them is a light emitting element 1.
4a, 15a and the light receiving elements 14b, 15b.

Since the pressure plate open / close detection sensor 12 (ASW1) detects the closing of the pressure plate 10, the on / off threshold position is set at an angle of about 30 degrees between the pressure plate 10 and the contact glass 11. Further, the pressure plate opening / closing detection sensor 13 (ASW2) detects that the pressure plate 10 is completely closed.

FIG. 3 is an explanatory view showing the relationship between the arrangement position of the document detecting sensor and the document size.
(S1) detects the A4 size, and the document detection sensor 15
(S2) is adapted to detect the A3 size.

FIG. 4 is a flowchart of the document size determination process by each document detection sensor. If S2 is on (YES in P1), the document size is determined to be A3 (P2). If S2 is off (NO in P1), S
When 1 is on (YES in P3), it is determined that the document size is A4 (P4). When S2 is off (NO in P1) and S1 is also off (N in P3)
O) determines that the document size is unknown (P
5).

By the way, the pressure plate 10 or A (not shown)
If the DF (Automatic Document Feeder) is completely closed,
The original detection sensors 14 and 15 are turned on regardless of whether the original is placed on the contact glass 11 (because the back surface of the pressure plate 10 or the ADF is white and the light from the light emitting element is reflected and enters the light receiving element). ), The original size cannot be detected.

Therefore, in this embodiment, the document size is detected by combining the document detection sensor output when only ASW1 detects closing and the document detection sensor output when ASW2 also detects closing. That is, at the moment when the pressure plate 10 is closed, the outputs of the document detection sensors 14 and 15 are latched to recognize the document size.

FIGS. 5A and 5B are flow charts of document detection control according to the first embodiment.

First, if the print switch is on (YES in P11), the program P20 is entered. If the print switch is off (NO in P11), ASW1
Detects the closing → opening of the pressure plate 10, in other words, the pressure plate 1
When 0 is opened 30 degrees or more (YES in P12), the contents of memory areas REG1 and REG2 are cleared (P1).
7). Further, when the ASW1 is detected from open to closed, that is, when the pressure plate 10 is closed to 30 degrees or less (YES in P13), the output of the document detection sensor is latched (P18) and the content is stored in the memory area REG1. (P19). Further, when the ASW 2 detects that the pressure plate 10 is completely closed (YES in P14), the document detection sensor output at that time is latched (P15). And memory area RE
The exclusive OR is taken with the memory contents of G1 and the result is stored in the memory area REG2.

When the print switch is turned on (P11
YES), it is determined whether the ASW1 is on, and if the pressure plate 10 is closed (YES in P20), it is determined whether there is information in the memory area REG2 (P23).
If there is no information, the contents of the memory area REG1 are moved to the memory area REG2, and if there is information, the program P25 is directly executed. If the pressure plate 10 is not in the closed state (P2
0 for NO), latches the original detection sensor output (P2
1), the memory is stored in the memory area REG2 (P22).
Next, the document size is determined according to the contents of the memory area REG2 (P25), the light emission of the document detection sensors 14 and 15 is stopped (P26) to prevent the unwanted light from entering the optical path, and then the copying operation is started (P27). ). After the copying operation is completed, the light emission of the document detection sensors 14 and 15 is restarted (P28) to prepare for the next document size detection.

FIG. 6 is a circuit diagram of the light emitting element and the light receiving element. Light emission can be stopped by turning off the light emitting signal of the light emitting element 14a shown in the figure.

Further, the light emission of the document detection sensors 14 and 15 may be synchronized with the light source for reading the document or the scanning motor. That is, when the light source is emitting light, the document detecting sensors 14 and 15 are turned off, when the light source is off, the document detecting sensors 14 and 15 emit light, or when the motor is rotating, the document detecting sensor is turned off. The same effect can be obtained by emitting light when stopped.

FIG. 7 is a schematic diagram of the optical system, and FIG. 8 is a waveform diagram showing a state detection signal indicating a period in which the original cannot be detected by the carriage.

In FIG. 7, reference numeral 21 is a light source, 22 is a reflecting mirror, 23 is a holding member for holding the light source 21 and the reflecting mirror 22, and a carriage for moving the light source 21 to perform a scanning operation is formed. ing.

As is apparent from this configuration, when a carriage comes above the document detection sensors 14 and 15, the document size cannot be detected by the document detection sensors 14 and 15. Here, by the carriage position detection circuit 6 of FIG.
The state detection signal shown in FIG. 8 is output during the period from the solid line position in FIG. 7 to the dotted line position in FIG.
The control shown in (b) is performed.

FIGS. 9A and 9B are flow charts of the document detection control according to the second embodiment, which is the program P3.
Although 1 to P46 are almost the same as those in the first embodiment shown in FIG. 3, the control portion based on the above-mentioned state detection signal will be described.

As described above, the carriage position detection circuit 6 outputs a state detection signal for the period until the carriage moves from the solid line position to the dotted line position in FIG. 7 and delays the document detection sensor output by the delay circuit 9 for this period. When it is necessary to check the outputs of the document detection sensors 14 and 15 by generating the generated signal as well, first check the above-mentioned state detection signal, and if it can be detected (NO in P35, N in P39).
O), the sensor output is input (P43, P40), and if it is in the undetectable period (YES in P35, YE in P39).
S), a signal obtained by delaying the sensor output is adopted as an input (P36, P41).

[0032]

According to the inventions of claims 1 to 3,
Since the light emission of the document detection sensor is prohibited during the copying operation, it is possible to prevent the light emission of the document detection sensor from adversely affecting the copied image without increasing the cost or increasing the weight of the apparatus.

According to the fourth and fifth aspects of the present invention, even if the carriage interferes with the optical path of the document size sensor, the sensor output before interruption can be obtained. Therefore, during the return operation of the carriage, the document is replaced and the pressure plate is moved. After closing, the new document size can be detected correctly even if the print switch is pressed.

[Brief description of drawings]

FIG. 1 is a control block diagram of essential parts of a copying apparatus according to an embodiment of the present invention.

FIG. 2 is a side view of the vicinity of contact glass.

FIG. 3 is an explanatory diagram showing the relationship between the arrangement position of the document detection sensor and the document size.

FIG. 4 is a flowchart of a document size determination process by each document detection sensor.

FIG. 5 is a flowchart of document detection control according to the first embodiment of the present invention.

FIG. 6 is a circuit diagram of a light emitting element and a light receiving element.

FIG. 7 is a schematic diagram of an optical system.

FIG. 8 is a waveform diagram of a state detection signal indicating a period in which an original cannot be detected by a carriage.

FIG. 9 is a flowchart of document detection control according to the second embodiment of the present invention.

[Explanation of symbols]

 1 Control Unit 2 Lamp Control Circuit 3 Illumination Lamp 6 Carriage Position Detection Circuit 7 Pressure Plate Open / Close Detection Circuit 8 Original Size Detection Circuit 9 Delay Circuit 10 Pressure Plate 11 Contact Glass 12, 13 Pressure Plate Open / Close Detection Sensor 14, 15 Original Detection Sensor 14a, 15a Light Emission Element 14b, 15b Light receiving element

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] November 27, 1992

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

[Figure 5]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Correction target item name] Figure 9

[Correction method] Change

[Correction content]

[Figure 9]

Claims (5)

[Claims] 1. An illuminating means for illuminating an original placed on an original table for a copying operation, a driving means for scanning the original, and a position corresponding to the original size, which are respectively arranged, and a power switch is turned on. Is lit by the light-emitting means and emits light in opposition to the placed document, a plurality of light-receiving means for respectively receiving the reflected light from the document due to the light emission of the plurality of light-emitting means, and a light-receiving signal from the light-receiving means A copying machine having a discrimination means for discriminating the size of an original, comprising a control means for prohibiting the light emission of the light emitting means. 2. The copying apparatus according to claim 1, wherein the control means performs control to prohibit the light emission of the light emitting means while the illumination means is on. 3. The copying apparatus according to claim 1, wherein the control means performs control to prohibit the light emission of the light emitting means while the driving means is operating. 4. An illumination means for illuminating an original placed on an original table for a copying operation, a driving means for scanning the original, and a position corresponding to the original size, which are respectively arranged, and a power switch is turned on. Is lit by the light-emitting means and emits light in opposition to the placed document, a plurality of light-receiving means for respectively receiving the reflected light from the document due to the light emission of the plurality of light-emitting means, and a light-receiving signal from the light-receiving means In a copying apparatus having an identification unit for identifying the size of a document, a state detection unit for detecting whether or not the document detection unit configured by the light emitting unit and the light receiving unit is in a state in which normal detection operation is impossible,
And a delay unit that delays the output of the document detection unit for a predetermined period. 5. The state detecting means according to claim 4, wherein the state detecting means outputs a signal during a period in which an object obstructing the detection of the original size passes between the original detecting means and the placed original in the operating state of the apparatus. A copying machine characterized by the above.