JP2582085B2 - Image forming device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a copying machine, and more particularly to an image forming apparatus having an automatic document feeder (hereinafter abbreviated as ADF). .

[Conventional technology]

Conventionally, various image forming apparatuses equipped with an ADF have been proposed, but no countermeasures have been taken for a document left behind on a contact glass by a previous operator. If there is a misplaced document and the ADF is used to feed in the document without knowing it, the document will be jammed.When the document is removed, not only will the document be torn or wrinkled, but also the copy time required to remove the document Disadvantages such as increased losses.

To solve such a problem, for example,
The following proposals have been made in JP-A-55-130530 and JP-A-61-270740, respectively. That is, in the former, when a copy operation is started using the automatic document feeder, if there is a document on the platen, the document on the platen is discharged by the automatic document feeder, and then the next document is discharged. Is fed onto the platen to start the copying operation.
In the latter case, a detecting means is provided at the entrance of the paper discharge section of the automatic document feeder, and when the detecting means detects a misplaced document, the automatic document feeding operation is stopped.

However, in the above-described conventional technology, the presence or absence of a document on the document table is determined each time a copying operation is started, and the automatic document feeding operation is stopped when a misplaced document is detected. Stopping operation causes a decrease in operation efficiency.

〔Purpose〕

The present invention provides an image forming apparatus with excellent operation efficiency that can detect a misplaced document and discharge the misplaced document by an automatic document feeder without causing unnecessary determination operation or operation stop of the apparatus. The purpose is to:

〔Constitution〕

In order to achieve the above object, the present invention provides an opening / closing detecting means for detecting the opening / closing of an automatic document feeder, and an image forming method based on the opening / closing detecting means detecting the opening operation of the automatic document feeding apparatus during an image forming operation. A pressure plate mode storing means for determining that the forming operation is performed in the pressure plate mode and storing the mode; and selecting an automatic original feeding mode when the next image forming operation is started after a series of the image forming operation is completed. Document presence detection means for detecting the presence or absence of a document on the document placement surface when the pressure plate mode storage means stores the pressure plate mode; and When the is detected, there is provided a discharging means for discharging the document on the document placing surface.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a copying machine according to an embodiment. As shown in the figure, on the upper part of the apparatus main body 2 having the photosensitive drum 1,
An optical unit 3 is provided, and further above the ADF 4 is rotatably mounted. The ADF 4 includes a document table 5, a call roller 6, a set sensor 7, a registration sensor 8, a transport belt 9, a paper discharge sensor 10, and a paper discharge roller.
11 and the like, so that the set originals are automatically fed one by one onto a contact glass (not shown) of the optical unit 3 (original mounting surface).

FIG. 2 is a schematic configuration diagram of the optical unit 3. As shown in FIG.
Below the contact glass 12, an exposure lamp 13 and a reflector
14, first mirror 15, second mirror 16, third mirror 17, fourth
A mirror 18, a dustproof glass 19, a lens 20, and a sensor 21 for detecting a document size and a document density are provided at predetermined positions.

In a copier equipped with an ADF, when a previous operator lifts up the ADF without using the automatic original feed mode and copies in the platen mode where copying is performed using the original as a platen, the original is placed on the contact glass. Often misplaced. Therefore, in the present invention, before setting the automatic document feed mode and performing the copying operation, it is detected whether there is any document left behind on the contact glass. For this document detection, for example, a document size sensor and a document density sensor can be used.

The check of the left document and the subsequent processing can be divided into the following four processes.
That is, a check process of whether or not to detect a misplaced document.

A check process of the timing of detecting a misplaced document.

The process of detecting misplaced documents.

Processing after detecting a misplaced document.

Next, each of these processes will be described together with a flowchart.

A check process for determining whether to detect a misplaced document.

FIG. 3 is a flowchart showing a subroutine of this check process. As shown in the figure, when this routine starts, it is determined in S1-1 whether or not the DF lift-up switch (open / close detection means) was turned on during the previous copy operation.
That is, it is determined whether the DF (document feeder) has been lifted up and used as a pressure plate. If YES, the check start flag is set to 1 in S1-4 because there is a possibility that the document is left behind. When it is determined in S1-2 that the forgotten document flag is 1, the forgotten document may have been removed. Therefore, the forgotten document flag is reset to 0 in S1-3, and the check is performed in S1-4. Reset the start flag to 1.

The check start flag is set to 1 when the power is turned on and when the apparatus returns to the standby state from the preheating mode.

Timing Check Process for Detecting Misplaced Documents This check process is limited to only when the document is fed by the DF while the check start flag is set. In other words, in the normal DF use copy process, when the timing of the DF original feed comes, the check processing may be performed before the feed.

FIG. 4 is a flowchart showing a subroutine of this check process. In this routine, S2-1 is a step for judging whether the DF is equipped and the transmission and reception between the DF and the control unit are normal. S2-2 is a step for calling a subroutine (described later) for detecting the presence or absence of a misplaced document. S2-3 is a step for judging whether or not a subroutine for detecting the presence or absence of a document left behind has been passed.
Thereafter, in S2-4, it is determined whether or not the forgotten document presence flag 1 is set.
If so, the process proceeds to a processing routine after detection of a forgotten document (described later).

Step of Detecting Misplaced Document If the above-described condition is satisfied and the detection processing is performed, the routine shown in FIG. 5 is started. S3-1 during this routine
It is confirmed that the scanner of the optical unit is in the home position as shown in FIG. In S3-2, the data in the previous copying process or the like is cleared.
Then, in S3-3, data is read from the automatic density sensor, and in S3-4, data is read from the document size sensor. In this way, the detection of a misplaced document
This is performed from both the document density detection and the document size detection.

Here, various characteristics relating to automatic density detection and document size detection will be described with reference to FIGS. 7 to 9. FIG.

FIG. 7 is a spectral reflectance characteristic diagram of the ADF transport belt 9 (see FIG. 1). In the figure, a region indicated by oblique parallel lines is a region of the spectral reflectance allowed for the ADF transport belt 9 of this embodiment. As is clear from this figure, the reflectance is small on the short wavelength side (up to 460 nm), and it looks yellow when visually observed.

FIG. 8 is a graph showing spectral reflectance characteristics of various originals. Curve 1 in the figure is a spectral quality characteristic of white fine paper, curve 2 is yellow (green) paper, curve 3 is recycled paper such as newspaper, and curve 4 is blue spectral paper.

FIG. 9 is a sensitivity characteristic diagram showing sensitivity characteristics of the size detection sensor, the density detection sensor, and the photosensitive drum. In the figure, curve a is the light receiving sensitivity characteristic of the size detection sensor, curve b is the light receiving sensitivity characteristic of the density detection sensor, and curve c.
Represents the light receiving sensitivity characteristics of the photosensitive drum under the predetermined light emission characteristics of the exposure lamp and the predetermined transmission characteristics of the lens.

As apparent from these figures, the density detecting sensor has a spectral characteristic close to the drum sensitivity characteristic, and detects the density of the document surface at the document reflection level.

On the other hand, the size detection sensor detects a difference between a conveyance belt having a low reflectance (yellow) in a short wavelength band having a low drum sensitivity and a document having a relatively high reflectance. Therefore, the presence or absence of a document can be determined based on the output value and the output difference of both sensors.

The following table shows specific output values of each sensor when there is a document and when there is no document.

The timer 1 is provided for measuring the time required for starting the exposure lamp, and the timer 2 is provided for measuring the time required for checking whether the document has been forgotten.

Processing Step After Detecting Missing Document If there is no missing document, the subsequent copying process is continued. If there is a forgotten document, after the forgotten document counter is advanced, it is determined whether or not the value of the forgotten document counter has become 10 or more.
If the determination result is No, the process returns to the step S3-1 to perform the process of detecting the left document. If the result is Yes, the flag indicating that the document is left is set to "1". Then, the forgotten document counter, the timer 1, the timer 2, the check start flag, and the check processing flag are all reset, and the reading operation of the size detection sensor and the density detection sensor is ended, and the exposure lamp is turned off. Thereafter, the process proceeds to the routine of FIG. 6 through steps S2-3 and S4 of FIG.
At step -1, the document is discharged by the DF (discharge means). Thereafter, in step S4-2, it is determined whether or not the discharge of the misplaced document has been completed. If the determination result is No, in step S4-3, it is determined whether or not the document discharge jam, that is, whether or not the document discharge operation is abnormal. I do. Yes at step S4-2
If so, the forgotten document presence flag is set to "0", and then the DF performs normal automatic document feeding (S4-4) to create a copy of the fed document. Note that the discharge operation abnormality of the document is performed by a discharge sensor provided in the discharge roller unit of the DF.

FIG. 10 is a timing chart of various flags and the like. In the same figure, after power on, copy using DF,
After performing operations in the order of copying using the DF as a pressure plate and copying using the DF again, pressing the preheating key enters the preheating mode, then the preheating mode is released, and copying using the DF is repeated twice. It shows a time change of various flags and the like at the time of being turned off. The DF lift-up switch in the figure is turned on by restoring the DF, and is normally turned off when the original can be fed. When the check start flag is "1", the routine of the above step is processed, and when the check start flag is "0", the processing of the routine is unnecessary. The forgotten document presence flag is “1” when there is a document, and “0” when there is no document. First, when the power is turned on, the check start flag is set to "1". Thereafter, when the document is placed on the document mounting table 5 of the DF and the print key is pressed, the subroutine of step S2-2 in FIG. The flag is set to "1", and the misplaced original document is detected. In this case, since there is no misplaced document, the forgotten document existence flag remains at “0”. Next, copying is performed using the DF as a pressure plate, and the DF lift-up switch is turned on, so that the check start flag is set to "1". At this time, the subroutine of the process of detecting the presence or absence of a document left behind is not executed.

Thereafter, when a document is placed on the document mounting table 5 of the DF to perform copying using the DF and the print key is pressed,
As described above, since the check start flag is "1", the misplaced document is detected. In this case, it is determined that there is a misplaced document, and the misplaced document existence flag is set to “1”. As a result, DF becomes contact glass
After performing the operation of discharging the misplaced original on the document 12, the ordinary automatic automatic feeding operation of feeding the original placed on the original placing table 5 is performed to create a copy. After the copy operation, the user enters the preheating mode by pressing the preheating key.

Thereafter, the preheating mode is released, copying using the DF is performed, and a subroutine of a process for detecting the presence or absence of a misplaced document is executed in accordance with the check start flag that has become "1" due to the release of the preheating mode. However, in this case, there is no misplaced manuscript, so the forgotten manuscript presence flag is set to “0”.
The copy process is performed in which the document is automatically fed by the DF.

FIG. 11 is a schematic block diagram of the control unit. 51 in the figure
Is an optical control board, 52 and 53 are sensor units, 54 is a main control plate (press plate mote storage means, document presence / absence detection means), 55 is various input / output ports related to copying, 56 is a display segment for various key inputs, 57 Is an AC drive circuit, 58 is an exposure lamp, 59
Are various drive units such as heaters and motors, 60 is an operation unit, 61 is an option control board, 62 is an ADF control board, 63 is a registration sensor, and 64 is a set sensor.

〔effect〕

As described above, the present invention determines that the image forming operation is in the pressure plate mode based on the detection of the opening operation of the automatic document feeder during the image forming operation, stores the mode, and stores a series of the image forming operation. After the operation is completed, when the next image forming operation is started, the automatic document feed mode is selected, and when the previous image forming operation is stored as the pressure plate mode, the original on the document placing surface is The presence / absence of the document is detected, and when the presence of the document on the document placing surface is detected, the misplaced document is ejected. Therefore, the misplaced document is detected without causing unnecessary determination operation and operation stop of the apparatus. As a result, it is possible to discharge a misplaced document by the automatic document feeder, thereby improving the image forming operation efficiency.

[Brief description of the drawings]

The drawings are all for explaining the embodiments of the present invention,
FIG. 1 is a schematic configuration diagram of a copying machine according to an embodiment, FIG. 2 is a schematic configuration diagram of an optical unit in the copying machine, and FIGS.
FIGS. 4, 5 and 6 are control flow charts,
7, 8, and 9 are various spectral characteristic diagrams, FIG.
FIG. 10 is a timing chart, and FIG. 11 is a block diagram of the control unit. 2 ... Main unit, 3 ... Optical unit, 4 ... ADF, 12
... contact glass, 21 ... sensor.

Claims (1)

(57) [Claims] A pressure plate mode for copying a document placed on a document placing surface by using an automatic document feeder attached to the image forming apparatus main body so as to be openable and closable, and said automatic document feeder; Opening and closing detecting means for detecting the opening and closing of the automatic document feeder, in an image forming apparatus capable of selecting an automatic document feed mode for automatically feeding and copying a document placed on a document table. A pressure plate mode storing means for determining that the image forming operation is based on the pressure plate mode based on detection of the opening operation of the automatic document feeder by the open / close detection means during the forming operation, and storing the mode; After the image forming operation is completed, when the next image forming operation is started, the automatic document feed mode is selected, and when the pressure plate mode storage means stores the pressure plate mode, upper And document presence detection means for detecting the presence or absence of paper, when the document presence detection means detects the original chromatic on the document placement surface, the image forming apparatus characterized by having the original unit.