JPH0439217A - Picture image forming device - Google Patents

Abstract

PURPOSE:To enable the detection of information about the dimensions of paper sheets with a small number of signal wires even if there are numerous kinds of recording paper by providing a control part for detecting the dimensions of a picture-image recording medium in accordance with the voltage that is produced when at least one of a plurality of switches is operated by projections corresponding to the dimensions of the medium in a housing means. CONSTITUTION:Projections 8-2 provided at the foremost end or on the rear end surface or on the side surfaces of a partition plate, a partition plate 8-3, and a magnet 8-4 are placed in the positions corresponding to the dimensions of picture-image recording medium P that is housed inside a feed-paper cassette 8-1a or 8-1b. On the other hand, in the picture-image forming device in which the feed-paper cassettes are installed, a paper-size detecting device 20a is provided, and the switches 4-1, 4-2 corresponding to the selected size of the feed- paper are turned on or off by the contact of the projections 8-2 corresponding to the various paper sizes, e.g. JIS A3, B4, A4, A5, and the magnet 8-4. Then, this signal is input into an A/D converter 4-5, and the dimensional information of the picture-image recording medium P, 8-5 housed inside the feed-paper cassette can be detected by a microprocessor 4-6.

Description

Detailed Description of the Invention [Objective of the Invention] (Industrial Field of Application) The present invention relates to improvement of an image forming apparatus, and more specifically, to improving the dimensions of recording paper stored in a paper feed cassette, that is, the image recording medium. The present invention relates to an image forming apparatus in which information can be easily detected by a small size detection device.

(Prior art) In image forming devices such as copying machines and laser printers,
There are various sizes of recording paper used for image formation, such as A4.84, and it is necessary to control the timing of image formation and alignment to suit each size. therefore,
It is necessary to know the dimensions of the recording paper in advance before image formation. Conventionally, methods for detecting the dimensions of this type of recording paper include (a) a method of detecting from the paper feed cassette that stores the recording paper, and (b) a method of detecting the size from the paper feed cassette that stores the recording paper, and (b) a method of detecting the size from the paper feed cassette that stores the recording paper. A method using a jam (paper jam) detection switch is known. Among these methods, method (a) uses the paper feed cassette (8-1) as shown in FIG. 8(a).
a) Recording paper (8-
5) Multiple protrusions (8-2), (8-2) according to the dimensions of
,... are provided, and these protrusions (8-2), (8-2),...
As shown in FIG. 9, the projection (8-2) of the paper feed cassette (8-1a) is used as a dimension detection device 20 to display the dimensions of the recording paper (8-5) depending on the combination of...
, (8-2), ... with the same number of Sui Sochi (9-1)
, (9-1), ... are provided, and protrusions (8-2), (
8-2), ... and the combination of on and off of the switch are converted into a binary code.

One end of the switches (9-1), (9-1), . . . is connected to a microprocessor (hereinafter referred to as It is simply abbreviated as rMPUJ.

) (9-2), and electrical leads (9-3), (9
-3), ... are connected to a DC voltage source (+5V). Furthermore, switches (9-1), (9-1),...
The other end is grounded and connected to the projection (8-1a) of the paper feed cassette (8-1a).
8-2) contacts the switch (9-1), and the switch (
9-1), the DC voltage will be applied to the electric lead wire (9-1).
3) to the ground side and the MPU (9-2) does not detect the voltage due to the closing of the switch (9-1).
1a) The dimensions of the stored recording paper (8-5) are detected.

The paper feed cassette (8-1a) described above has a partition at the rear end of the paper feed cassette (8-1b) according to the length of the recording paper (8-5), as shown in FIG. 8(b). Board (8-3) (
In general, a device may be used in which a plurality of magnets (generally, a plurality of magnets are arranged according to the difference in size) and a small magnet (8-4) is installed on the side of the partition plate (8-3), and in this case also, the above-mentioned dimension detection device can be used.

In the above method ((a)), as the types of recording paper dimensions increase, the number of signal lines increases accordingly, and the MPU
Since the number of poles of the harness and connector that connects (9-2) and switch (9-1) increases, this poses a problem in that it impedes miniaturization and cost reduction of the dimension detection device.

From the point of view of reducing the number of signal lines in a dimension detection device, a device 21 having the configuration shown in FIG. 10 is conventionally known. A parallel/serial conversion circuit (hereinafter referred to as rP/S conversion circuit) converts the signal of the switch 4 in accordance with the difference in the dimensions of the recording paper (8-5) stored in the paper feed cassette.>(10-
1), and serial/parallel conversion circuit (hereinafter referred to as “S
/P conversion circuit". ) (10-3) is used to reduce the number of signal lines. However, there are still 4 lines (+5V), serial clock line (10-5), and serial data line (1
0-6) and SG wire (10-7)) are required. Furthermore, a P/S conversion circuit (102) and an S/P conversion circuit (
10-3) circuit (IC) is required. therefore,
This cannot be said to be sufficient for the purpose of reducing the cost and size of image forming apparatuses. In particular, recently there have been many requests to purchase an image forming apparatus to which a plurality of optional paper feeders are connected, and this has led to the problem of an increase in the number of signal lines provided in the dimension detection apparatus.

Further, as a conventionally known method for detecting paper size in an image forming apparatus, a method as shown in FIG. 11 is also known.

In this method, the image recording medium (not shown in FIG. 11) in the paper feed cassette (11-1) is transferred to the paper feed roller (11-1).
-2) and aligning roller (11-4).
The photosensitive drum (image carrier) is stopped at
11-5) At the stage when the original image is recorded on the paper, the conveyance of the stopped recording paper is started. At this time, this method attempts to detect the length of the recording paper from the time during which the jam switch (11-3) is pressed by the conveyed recording paper. However, this method does not work with the photoreceptor drum (11-
5) Since the length dimension cannot be detected before the document image is recorded, it has the problem that it cannot be used in devices such as printers that require recording paper dimension information before paper feeding. ing.

(Problems to be Solved by the Invention) Therefore, the present invention provides an image forming apparatus having a dimension detection means that can detect recording paper dimension information with a small number of signal lines even if there are many types of recording paper dimensions. This is what I am trying to do.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, an image forming apparatus according to claim (1) is an image forming apparatus including a storage means for storing an image recording medium. , a plurality of protrusions installed at different positions according to the dimensions of the image recording medium to be stored in the storage means, a plurality of switches operated by the protrusions and outputting different voltages, and the plurality of switches. and a control section that detects the dimensions of the image recording medium according to the voltage generated when at least one of the four switches is operated by the protrusion of the storage means.

Further, the image forming apparatus according to claim (2) is provided with an analog-to-digital conversion section between the switch and the control section of the image forming apparatus according to claim (1), and converts the analog output voltage generated at the switch. The analog signal is connected via a common signal line.
This is characterized in that the information is input to the control section by a digital conversion section.

Further, in the image forming apparatus according to claim (3), the output voltages generated in the plurality of switches of the image forming apparatus according to claim (2) are connected to an analog signal line through a common analog signal line through respective diodes. - It is configured to be input to the digital conversion section.

(Function) Therefore, in the image forming apparatus according to claim (1), the storage means is provided with a plurality of protrusions arranged at different positions according to the dimensions of the image recording medium, and the plurality of protrusions output different voltages at the time of switching. Since the switch provided with the plurality of switches inputs the output voltage generated by the operation of the protrusion of the accommodation means and detects the size of the image recording medium, the size of the image recording medium can be detected even if the number of signal lines is not large. Information can be easily detected.

Further, in the image forming apparatus according to claim (2), an analog-to-digital conversion section is provided between the switch and the control section, and the analog output voltage generated at the switch is transmitted to the analog/digital converter through a common signal line. Since the size information of the image recording medium can be detected as a digital signal by inputting it to the control section through the digital conversion section, a small number of signal lines can be used.

Furthermore, in the image forming apparatus according to claim (3), the output voltages generated in the plurality of switches are inputted to the analog-to-digital conversion section via a common analog signal line via diodes, and further passed through the control section to the dimensional converter. Since information is detected, the size information of the image recording medium can be detected as a digital signal using the minimum number of signal lines.

(Example) Hereinafter, an image forming apparatus according to a typical example of the present invention will be described based on the drawings.

FIG. 1 is an external perspective view of the image forming apparatus of the present invention, in which (1-1) is the main body of the apparatus, (1-2) is an envelope feeding device,
(1-3) is a multiple set paper feeding device. Figure 2 is the first
FIG. 3 is a vertical cross-sectional view showing the internal configuration necessary for explaining the image forming apparatus shown in FIG. Second
In the figure and Figure 3, (1-7) is the paper feed cassette (1-5
), the paper feed roller (1-8) takes out the image recording medium P and sends it into the image forming apparatus, and the paper feed roller (1-7
) transports the image-forming medium P fed out into the paper feed conveyance path; (110) is a photosensitive drum that records the original image; (111) is the image-recording medium P that has been conveyed; A transfer charger (1-12) is a fixing device that heats and fixes the image transferred to the image recording medium P.

The paper feed cassette of the image forming apparatus of this embodiment, for example, the top paper feed cassette (1-3) in the multiple set paper feed device (1-3).
-4) is (8-1B) in Figure 8(a) or (8-1B) in Figure 8(b).
), like (8-1b), there is a protrusion (8-2) on the front or rear end surface of the cassette.

...or a magnet (8-4) on the side of the partition plate (8-3).
). These protrusions (8-2)...
The partition plate (8-3) and the magnet (8-4) are located at positions corresponding to the dimensions of the image recording medium P accommodated in the paper feed cassettes (8-12) and (8-1b).

On the other hand, the image forming apparatus to which the above-described paper feed set is installed is provided with a paper size detection device 20a having a circuit configuration shown in FIG. This paper size detection device 20a has the above-mentioned projections (8-2), (8-2), . . . corresponding to various paper sizes (for example, Japanese Industrial Standards A3, B4.A4.A5);
By contact with the magnet (8-4), the switches (4-1), . . . , (4-1) corresponding to the switch (4-1) are turned on/off.

These switches (4-1), (4-1),...
- (4-1) may be a mechanical switch or a reed switch. Each switch (4-1, (4-1).

... (4-1) are connected to voltage dividing resistors (4-2), respectively. For example, if each resistor is 1000 ohms, when the A3 switch (4-1) is turned on to one analog signal line (4-4), the +5VSBJ switch (4-1) is turned on.
Approximately 3°4V when on, A4 switch (4-1> Approximately 1.7V when on, A5 switch (4-1), OV when on is diode (4-3), (4-3),... The A/D converted digital voltage is input to an analog-to-digital converter (hereinafter referred to as rA/D converter) (4-5), and the A/D-converted digital voltage is input to a microprocessor (4-6).
), the image recording medium P accommodated in the paper feed cassette
(8-5) dimension information can be detected.

Here, the diodes (4-3), (4-3), ... (
4-3) is a switch (1-1, (4-1).

If two or more are accidentally pressed at the same time and turned on,
so that a voltage corresponding to the larger paper size is generated,
Even if the image recording medium is not of an appropriate size, a large recording paper is selected so that the recorded image does not protrude from the image recording medium.

In addition, in FIG. 4 (the same applies to FIGS. 6, 9, and 10), the display in parentheses is LEDGER.

LEGAL, LETTER, and STATEMENT indicate the rated dimensions of paper used in the United States and Canada. Generally, the rated dimensions of the image recording medium are A row 5 (A5) to A row 3 (A3) in Japan and Europe;
In the US and Canada, STATEMENT to LEDG
ER is used.

If the image forming apparatus has separate destinations as described above, the paper size detection switch is either a four-type image forming apparatus as shown in FIG. 4, or a diode or If you increase the voltage dividing resistor and connect the cathodes of the diodes together, A5
~A3 and STATEMENT to LEDGER can be detected by the same detection circuit. Moreover,
The number of signal lines between the MPU section and the switch section remains unchanged.

Further, the dimension detection device for an image forming apparatus according to the present invention has a fifth dimension detecting device.
When using the paper feed cassette (5-1) with the structure shown in the figure, in order to detect the paper size of the image recording medium (5-2) stored in the paper feed cassette, the circuit configuration shown in Fig. 6 is used. Good too.

That is, the image recording medium (5-2) is stored in the paper feed cassette (5-1), and the image recording medium (5-2)
) A partition plate (5-3) is arranged at the rear end position. Furthermore, a protrusion (5-4) is provided on the side of this partition plate (5-3).
Or is provided. This paper feeding force (5-1) is
When attached to an image forming apparatus (not shown in FIG. 5), it is inserted in the direction of arrow C. A variable resistor (5-5) is attached to the image forming device side, and the paper feed cassette (
When inserting 5-1 in the direction of arrow C, the protrusion (5-4)
presses the sliding resistance (5-5), so the sliding resistance (5-5)
The position of 5) changes depending on the paper size of the image recording medium (5-2). A coiled spring (5-6) is attached to the sliding resistor (5-5), and the paper feed cassette (5-5)
1) is configured to return to its original position when it is pulled out.

In the dimension detection circuit 21a of FIG. 6, both ends of the sliding resistor (6-1) are connected to the DC power supply +5V and SG, and the slider is
connected to the D converter (6-2), and connected to the A/D converter (6-2).
) is manually input to the MPU (6-3). Paper feed cassette (5-1) Depending on the paper size stored in the paper feed cassette (5-1),
-1) The position of the protrusion (5-4) on the side surface changes, and an analog voltage is generated corresponding to the paper size (for example, A5 to A3), which is output to the A/D converter (6-2). Similarly to the paper size detection circuit shown in FIG. 4, in the case of the paper size detection circuit shown in FIG. 6, if the destination of the image forming apparatuses is the same,
This is made possible by finely matching the divided voltage ranges corresponding to A5 to A3 and STATEMENT-LEDGER. If the relationship between the paper size and the output voltage according to the sliding resistance method is shown, characteristic diagrams such as those shown in FIGS. 7(a) and 7(b) can be obtained.

However, Fig. 7(a) is a characteristic diagram when the paper size (length) and output voltage are proportional, and it shows the characteristics of LETTER and A4.
The longitudinal dimensions are 279゜4mm and 297mm as shown.
When the difference in output voltage is small, it is possible to increase the difference in output voltage by using a sliding resistor with an exponential characteristic as shown in FIG. 7(b).

In addition, in order to detect whether the paper feed cassette is installed in the image forming apparatus, the slider of the sliding resistor moves to the end of the sliding resistor, and the voltage at the SG level is applied to the A/D converter ( 6-2
). By the way, the fourth
In the paper size detection circuit configured as shown in the figure, the switch (4-1),
(4-1).

When ... is completely off, SG is turned off by resistor (4-7).
Since the level voltage is output to the A/D converter (4-5), the state of "no cassette" can be known. The voltage dividing resistor (4-7) has a larger resistance value than (4-2). In addition, the voltage value output according to the paper size and the "no cassette" state is determined by the shutter (4-1) (4-1), ...; voltage dividing resistor (4- 2
), (4-2), diode (4-23), (4
-3),... and the connection method of the resistor (4-7), the paper size detection device shown in Figs. You can change it freely.

The dimension detection devices shown in Figs. 4, 5, and 6 have the advantage of minimizing the number of signal lines between the switch section and the MPU section, and the switch shown in Fig. 4 can be replaced with a reed switch, etc. If a non-contact switch is used, it is suitable for non-contact paper size detection, and the paper feed cassette shown in FIG. 5 is suitable for contact paper size detection.

[Effects of the Invention] As is clear from the above description, according to the image forming apparatus of the present invention, the storage means has a plurality of protrusions arranged at different positions depending on the size of the image recording medium to be stored. In addition, a plurality of switches each outputting a different voltage at the time of switching are used for dimension detection.
Since the voltage generated when at least one of the plurality of switches is operated on the protrusion of the storage means is inputted to the control section, it is possible to reduce the size of the image recording medium without increasing the number of signal lines. Information can be easily discovered.

In the image forming apparatus according to claim (2), an A/D converter is provided between the switch section and the control section, and the analog voltage generated in the switch section is transmitted to the A/D converter via a common signal line. Since the size information of the image recording medium is input to the control unit and detected as a digital signal, the number of signal lines can be reduced.

Furthermore, in the image forming apparatus according to claim (3), the output voltage generated in the switch is inputted to the A/D converter through a diode and a common analog signal line, and the dimensional information is detected by the control unit. A real analog signal line can be used, and the dimension detection means can be miniaturized.

[Brief explanation of the drawing]

FIG. 1 is an external perspective view of an image forming apparatus according to an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing the internal configuration of the image forming apparatus of FIG. 1, and FIG. 3 is an enlarged view of the main parts of FIG. 2. 4 is a circuit configuration diagram of a paper size detection device according to the first embodiment of the present invention, FIG. 5 is an external perspective view of a paper feed cassette used in the paper size detection device of this invention, and FIG. The figure is a circuit configuration diagram of the paper size detection device for the recording paper in the paper feed cassette shown in Figure 5, and Figures 7 (a) and (b) are the paper size detection device using the sliding resistance method.
A characteristic curve diagram showing the relationship between the length) and the output voltage, and a characteristic curve diagram showing the relationship between the paper dimension (length) and the output voltage using a resistor having an exponential sliding resistance characteristic, Figure 8 (a),
(b) is an external perspective view showing the configuration of a paper feed cassette used in a conventional image forming apparatus, FIG. 9 and FIG.
FIG. 0 is a circuit configuration diagram of a conventional size detection device for recording paper stored in a paper feed cassette, and FIG. 11 is a basic recording configuration diagram showing an aspect of a paper size detection method using a conventional paper feed cassette. 4-3...Diode 5-1.8-1a, 8-1b, 11-1-Paper feed cassette 4-4.6-4.10-5.10-6...Signal line 4-
5.6-2...A/D converter 4-8゜0-7...SG line

Claims (3)

[Claims] (1) In an image forming apparatus equipped with a storage means for storing an image recording medium, a plurality of protrusions installed at different positions according to the dimensions of the image recording medium to be stored in the storage means; a plurality of switches each outputting a different voltage when operated by a plurality of switches; An image forming apparatus comprising: a control section that detects the dimensions of the image forming apparatus. (2) An analog-to-digital conversion section is provided between the switch and the control section, and the analog output voltage generated at the switch is inputted to the control section by the analog-to-digital conversion section via a common signal line, and the image recording medium is input to the control section. Claim (1) characterized in that the dimensional information of is detected as a digital output.
). (3) The image forming apparatus according to claim (2), wherein the output voltages generated in the plurality of switches are inputted to the analog-to-digital converter through a common analog signal line through respective diodes.