JP2010032889A - Image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achive a circuit configuration capable of discriminating existence of a recording paper detection sensor and a recording paper detection signal by one signal line. <P>SOLUTION: A voltage divider means is connected with the recording paper detection sensor and the output of the sensor in parallel, and reading output voltage of the detection sensor by an analog/digital converter, thereby the state is discriminated. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an image forming apparatus such as a laser printer.

  A conventional image forming apparatus will be described with reference to FIGS. FIG. 5 is a cross-sectional view of an image forming apparatus such as a laser printer. In this figure, reference numeral 510 denotes a paper feed cassette that accommodates recording paper, and a recording in the paper feed cassette is provided above the paper feed cassette 510. A cassette paper presence sensor 502 for detecting the presence or absence of paper and a cassette paper feed roller 511 are provided, and the recording paper is conveyed by a conveyance roller 512 arranged in the recording paper conveyance direction of the paper supply roller 511. Downstream of the conveying roller 512 is a cartridge 513 containing an electrophotographic process forming means. A photosensitive drum 514 in the process cartridge is uniformly charged by a primary charger 508, and an image from an external device (not shown) is displayed. When the semiconductor laser 503 is turned on / off by the signal, the laser beam is irradiated onto the polygon mirror 501, and the reflected light is irradiated onto the photosensitive drum 514 via the imaging lens 504 and the reflecting mirror 505, the surface of the photosensitive drum 514. A latent image corresponding to the image signal is formed in. The latent image formed on the photosensitive drum 514 by the developing device 523 in the process cartridge becomes a visible image, and is transferred by the transfer roller 515 onto the conveyed recording paper. The recording sheet to which the visible image is transferred is conveyed toward the heat fixing device 518 and fixed as a permanent image in the fixing device 518. The recording sheet on which the image is fixed is discharged out of the apparatus by a discharge roller 517 and is stacked on a discharge tray 519. 509 includes a circuit for generating a DC power source for operating the image forming apparatus, a high voltage generation circuit necessary for the image forming operation, and an electric board equipped with a microcomputer, which controls the image forming operation. ing.

  An optional cassette 520 is detachable from the apparatus. An optional cassette paper presence / absence sensor 522 for detecting the presence / absence of recording paper in the optional cassette and an optional cassette paper feed roller 521 are provided above the optional cassette 520. When the sheet feeding operation is instructed from the electric substrate 509 to the option cassette, the recording sheet is conveyed from the option cassette sheet feeding roller 521 to the conveying roller 512, and the image forming operation is performed. Is called.

  FIG. 6 is a block diagram showing electrical connection between the option cassette 520 and the electric board 509. In FIG. 6, 101 is a microcomputer for controlling the image forming operation, and 103 is provided in the option cassette. The paper presence / absence detection sensor is supplied with current from the DC voltage Vcc through the resistor 106 to the light-emitting diode of the photo interrupter. The output terminal of the photo interrupter 103 is pulled up to a DC voltage Vcc by a resistor 107. When the light receiving transistor is turned on / off, the output voltage is switched between the DC voltage Vcc and the collector-emitter voltage Vce of the transistor. The presence or absence of paper is detected. Reference numeral 601 denotes a switch for setting the recording paper size of the optional cassette. The microcomputer 101 switches the size of the recording paper by switching the DC voltage Vcc and the GND level according to the pull-up resistor 603 to the pull-up resistor 605 and the switch setting. Recognize

Reference numeral 602 denotes a circuit for detecting the presence or absence of the photo interrupter 103. The microcomputer 101 detects whether or not the photo interrupter 103 is connected to the GND via the connector 104 and the connector 105, and the presence or absence of the photo interrupter and the presence or absence of the optional cassette. Is detected.
JP-A 63-66030

  In the above conventional example, since the means for detecting that an optional device such as an optional cassette is attached is individually provided, the configuration is complicated in proportion to the number of corresponding optional devices. In particular, when the recording paper size is set with an optional cassette or the like, a signal line corresponding to the type of the corresponding recording paper is required, which further complicates the configuration and causes a cost increase.

  In order to achieve the above object, the invention according to claim 1 of the present application is configured such that a voltage dividing means is connected in parallel with a paper presence / absence sensor provided in the optional device, and the output voltage of the sensor signal is analog / digital. It is read by a conversion device, and the configuration of the optional device and the presence or absence of recording paper are detected by a single signal line based on the voltage value.

  The invention according to claim 2 relating to the present application is characterized in that the main body configuration is discriminated when the power source is activated.

  The invention according to claim 3 relating to the present application is characterized in that the voltage is finely changed by connecting a plurality of voltage dividing means in parallel, and the configuration of the recording paper is determined in more detail, such as the size setting of the recording paper. .

  As described above, according to the present invention, the presence / absence and configuration of an optional device can be determined without increasing the number of signal lines.

  Next, details of the present invention will be described in accordance with the description of the embodiments.

  A first embodiment of the present invention will be described with reference to FIGS. 1 having the same functions as those in FIG. 6 are given the same numbers, and the description thereof is omitted.

  Reference numeral 102 denotes an analog / digital conversion device, which is built in the microcomputer 101 in this embodiment. Reference numeral 108 denotes a voltage dividing resistor R2 representing this embodiment, which is connected in parallel with the output terminal of the photointerrupter 103 and is divided by a pull-up resistor R1 107.

  FIG. 4 is a diagram illustrating a voltage range that varies depending on the presence or absence of an optional sheet cassette. As shown in FIG. 4, when the optional paper feed cassette 520 is not connected, the voltage input to the analog / digital conversion device is the same as Vcc. When the optional paper feed cassette 520 is connected and the light-receiving side transistor of the photo interrupter is off, the voltage input to the analog / digital conversion device divides the power supply voltage Vcc by the voltage dividing resistors R1 and R2. Voltage is input. When the optional paper feed cassette 520 is connected and the light-receiving side transistor of the photo interrupter is on, the voltage input to the analog / digital converter is the collector-emitter voltage of the photo interrupter. .

  According to this circuit configuration, it is possible to determine the presence / absence of an optional device and the presence / absence of recording paper from one output signal.

  A second embodiment of the present invention will be described with reference to FIG. 2 having the same functions as those in FIG. 1 are given the same reference numerals and explanations thereof are omitted.

  The difference between this embodiment and the first embodiment is that the voltage dividing resistor 201 is connected between the circuit to which the light-emitting diode of the photo interrupter 103 is connected and the collector terminal of the photo interrupter.

  According to this embodiment, when the light-receiving side transistor of the photo interrupter is off, the input impedance of the analog / digital converter is so high that the Vf voltage of the light emitting diode is input. Become. When the light-receiving side transistor of the photo interrupter is on, the voltage input to the analog / digital converter is the collector-emitter voltage of the photo interrupter.

  According to this configuration, it is possible to realize the same function with a cheaper configuration.

  A third embodiment of the present invention will be described with reference to FIG. 3, those having the same functions as those in FIG. 1 are given the same reference numerals, and description thereof is omitted.

  The difference between this embodiment and the first embodiment is that the recording paper size setting switch and the voltage dividing resistors 301 to 303 are connected between the collector terminals of the photo interrupter.

  According to this embodiment, since the divided voltage value is changed by turning on and off the size setting switch of the recording paper, it is possible to detect the presence / absence of the recording paper and the size information at the same time.

  In this embodiment, since the size information of the recording paper is required when there is paper in the cassette, the light-receiving side transistor of the photo interrupter is turned off when there is paper.

The block diagram which shows the 1st Example of this invention. The block diagram which shows the 2nd Example of this invention. The block diagram which shows the 3rd Example of this invention. The table | surface which shows this invention 1st Example. 1 is a cross-sectional view of an image forming apparatus. The block diagram which shows a prior art example.

Explanation of symbols

102 Analog / Digital Converter 108 Voltage Dividing Resistor 103 Photointerrupter

Claims (3)

In an image forming apparatus for forming an image on a recording material, a recording material detecting means;
DC voltage generating means for operating the image forming apparatus, a microcomputer that controls the operation of the image forming apparatus, a control board including an analog / digital conversion device connected to the microcomputer, and a photo interrupter Sensor board,
DC voltage dividing means for dividing the output voltage of the sensor substrate,
The DC voltage dividing means is connected in parallel with the output terminal of the recording material detecting means, and the presence or absence of the sensor board is obtained by reading the output voltage of the sensor board into the microcomputer via the analog / digital converter. And an image forming apparatus characterized by identifying the presence or absence of a detection target of the sensor.   An image forming apparatus characterized in that the presence or absence of the recording material detection means is determined by reading an output voltage from the recording material detection means when the microcomputer is activated.   An image forming apparatus comprising: a plurality of the DC voltage dividing means connected in parallel, and the recording material detecting means determining the configuration of the image forming apparatus by switching the connection of the DC voltage dividing means.

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