JPH06316365A - Control method for image recording device - Google Patents

Abstract

PURPOSE:To perform correction of the change with a year of a recording sheet sensor and to prevent the occurrence of a decision error by a method wherein when image recording operation is executed, the detecting signal level of a recording sheet sensor is read, and based on the detecting signal level, a threshold for deciding a recording sheet is set and varied. CONSTITUTION:A guide plate 3 is disposed facing a recording sheet sensor Sa and a thermal head 4 facing a platen roller 5 on a conveyance passage for a recording sheet 1, and a recording sheet sensor Sb and a cutter 7 are disposed at a stage followed thereby. Output signals from the recording sensors Sa and Sb are inputted to an electronic circuit. Digital signals (detecting signal levels) La and Lb after A/D conversion are compared with specified thresholds Ta and Tb and from a comparing result, the passage of a recording sheet through each spot is decided to monitor and control each part. In this case, the detecting signal levels La and Lb are read and it is decided whether abnormality occurs. In a case of normality, the thresholds Ta and Tb are calculated by multiplying the signal levels La and Lb by a specified factor R.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling an image recording apparatus for recording an image on a recording sheet while determining whether the recording sheet has passed on the conveying path by a recording sheet sensor.

[0002]

2. Description of the Related Art In the case of a facsimile machine using roll-shaped recording paper, when a new recording paper is loaded by an operator, the facsimile machine usually feeds the recording paper from a recording section to a paper discharge port once. Cut the tip. As a result, after the front end of the recording paper is shaped, the front end is returned to the fixed position of the recording unit. At the time of image recording, the paper is fed while sequentially recording the image one line at a time from the fixed position, and when the image recording is finished, the recording paper is fed to the paper discharge port and the recorded image portion is cut and discharged. To paper. Then, the leading end is returned to a fixed position on the recording unit.

In order to correctly execute such a movement of the recording paper, a recording paper sensor is provided at each point on the recording paper conveyance path to judge the passage of the recording paper.

In this case, a reflection type optical sensor is often used as the paper recording sensor. The reflection type optical sensor irradiates a recording paper with light by a light emitting element and detects the reflected light by a light receiving element. Then, when the signal level of the detection signal of the recording paper sensor is larger than a certain threshold value, it is determined that "paper is present", and when the signal level is less than the certain threshold value, it is determined that there is no paper.

The threshold value for determining the recording sheet is set in accordance with each device in the manufacturing process of the facsimile device.

[0006]

By the way, the signal level of the detection signal of the recording paper sensor is high when "paper is present" and is low when "paper is absent". Further, as shown in FIG. 8, the high and low signal levels fluctuate within a certain range due to the power supply voltage and temperature during operation, the difference in reflectance of light on the recording paper, and the like. Further, it has a property of gradually decreasing with age due to the secular change of the parts used.

At the time of manufacturing a facsimile machine, a threshold value is set between the high level and the low level. Now, as shown in FIG. 8, it is assumed that a constant value S between the two level ranges is set to the threshold value at the time T0 of manufacturing the facsimile apparatus. in this case,
After a certain period of time T1, “paper is present” is higher than the threshold value.
As a result, the signal level becomes low, and a recording paper determination error occurs.

Conventionally, in order to prevent such a determination error, a recording paper sensor having a good characteristic such as one having a large level difference between a high level and a low level of a detection signal or one having little secular change is used. I was going to use it.

However, such a recording paper sensor having good characteristics has a problem that the manufacturing cost of the sensor itself is difficult and the cost is high, so that the cost of the apparatus such as a facsimile machine using the sensor is also high.

The present invention solves the above problems and provides a control method for an image recording apparatus capable of preventing a recording paper judgment error without using a special recording paper sensor having good characteristics. With the goal.

[0011]

To this end, according to the present invention, when an image recording operation is executed, the detection signal level of the recording paper sensor is read and the recording paper determination is performed based on the detection signal level. It is characterized in that a threshold value that follows changes in the detection signal level of the recording paper sensor is automatically set by resetting the threshold value.

[0012]

[Effect] Even if the detection signal level changes due to the aging of the recording paper sensor, the threshold value that follows the change is automatically set. Therefore, even if a special recording paper sensor with good characteristics is not used, It is possible to prevent the judgment error of the recording paper.

[0013]

Embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

FIG. 1 is a schematic configuration diagram showing a mechanism of an image recording apparatus of an image recording apparatus according to an embodiment of the present invention. In the figure, a recording paper 1 is a roll-shaped thermal recording paper, and is placed on a tray 2. A guide plate 3, a recording paper sensor Sa, and a thermal head 4 are provided on the recording paper 1 conveyance path.
And the platen roller 5 are arranged so as to face each other. A recording paper sensor Sb and a cutter 7 are arranged further on the transport path. The recording paper sensor Sa and the recording paper sensor Sb are known reflection type optical sensors composed of a light emitting element and a light receiving element.

A device cover 8 is attached above the recording paper 1. The device cover 8 is opened / closed when the recording paper 1 is attached, and a cover switch SW for detecting the opening / closing is attached.

FIG. 2 is a block diagram of an electronic circuit of the image recording apparatus. In the figure, an image recording unit 9 drives the thermal head 4 in accordance with input image information to record an image on the recording paper 1. A / D converter 10
Is for converting the detection signals of the recording paper sensors Sa and Sb into digital signals. The operation display unit 11 is used by an operator to operate the device and / or the device displays an alarm indicating an abnormal state.

The recording paper transport unit 12 includes a platen roller 5
Is driven to feed the recording paper 1 along the conveyance path. The memory 13 stores threshold data for recording paper determination of the recording paper sensors Sa and Sb. The control unit 14 is a microcomputer that monitors and controls each unit.

When the image recording apparatus of the present embodiment is used with the above configuration, the recording paper 1 is first mounted. In this case, the operator opens the device cover 8 and receives the recording paper 1 in the tray 2
Then, the device cover 8 is closed again.

By the above operation, the image recording apparatus is initialized to a recording operation possible state. That is, as shown in FIG. 3, the image recording apparatus monitors the opening / closing of the device cover 8 (N loop of process 101), and when the device cover 8 is opened / closed as described above (Y of process 101). ), And reset the "paper out flag" (process 102). The "paper-out flag" is stored in the memory 13 and is set when the recording paper 1 runs out after the operation of the apparatus is started.

Next, the leading edge of the recording paper 1 is fed by a preset specified amount (process 103). As a result, the leading edge of the recording paper 1 is conveyed to the position where it passes the cutter 7. Here, the cutter 7 is operated to cut and shape the front end of the recording paper 1 (process 104).

Next, the signal level La of the detection signal of the recording paper sensor Sa and the signal level Lb of the detection signal of the recording paper sensor Sb are read (process 105). And
It is determined whether or not the read signal levels La and Lb are normal (process 106).

When the signal levels La and Lb are above a certain value, it is judged to be normal. In this case (Y of processing 106),
Based on those signal levels La and Lb and the coefficient R,
The threshold values Ta and Tb are calculated as Ta = La × R Tb = Lb × R. The coefficient R is preset with a constant value such as "0.7" (process 107). Then, the calculated determination threshold values Ta and Tb are stored in the memory 13
It is stored in and stored in (step 108). After this, recording paper 1
Is reversed by a preset specified amount and returned to a predetermined recording position P (process 109).

On the other hand, the read signal levels La and L
If b is less than a certain value, it is determined to be abnormal. Examples of cases that are determined to be abnormal include a case where the recording paper 1 is not mounted and a case where the recording paper sensors Sa and Sb are out of order. In this case (N in process 106), an alarm is displayed on the operation display unit 11 (process 110), and the "paper-out flag" is set (process 111).

This image recording apparatus starts the recording process by an operator's activation operation or activation control from an external device.

FIG. 4 and FIG. 5 show this recording process. That is, when starting the recording process, this image recording apparatus checks the above-mentioned "paper-out flag" (process 201). When the “paper out flag” is off (“off” in step 201), the detection signal of the recording sheet sensor Sa is read and the signal level La is compared with the stored threshold value Ta (step 202). . Here, when the recording paper 1 is at the position of the recording paper sensor Sa, the signal level La
Becomes larger than the threshold value Ta. In this case (process 202)
Y), and further, the detection signal of the recording paper sensor Sb is read, and the signal level Lb is compared with the stored threshold value Tb (process 203). Here, the recording paper sensor Sb
When the recording paper 1 is not present at the position, the signal level Lb becomes equal to or lower than the threshold value Tb. In this case (Y in process 203), image recording is started. That is, image information is sequentially input from an external device (not shown), and the recording paper 1 is sub-scanned, that is, sequentially fed while the image is recorded line by line with the thermal head 4 (process 204).

After that, the detection signal of the recording paper sensor Sa is read, and while monitoring that the signal level La is higher than the threshold value Ta (process 205, Y in process 205), image recording for one page is completed. (Process 20)
6. From N in process 206 to process 205). When the image recording for one page is completed (Y in process 206), the recording paper 1 is fed by the specified amount, and the trailing end of the recorded one page is conveyed to the position of the cutter 7 (process 207). Then, the recorded image of one page is cut (process 208).

Here, the signal levels La and Lb of the detection signals of the recording paper sensors Sa and Sb are read and temporarily stored (process 209). Then, the recording paper 1 is reversely fed by a preset specified amount and returned to the recording position P (process 21).
0).

After that, the detection signal of the recording paper sensor Sb is read and the signal level Lb is compared with the threshold value Tb (process 211). When the signal level Lb is equal to or lower than the threshold value Tb (Y in process 211), the process 209 is performed.
It is determined whether or not there is an abnormality in the signal levels La and Lb stored in (step 212). When both the signal levels La and Lb have a certain value or more, it is determined to be normal. In this case (Y in process 212), the threshold values Ta and Tb for determination are calculated from those signal levels La and Lb as in the process 107.
Is calculated (process 213) and stored in the memory 13 (process 214).

As a result, when the image is recorded next time, the presence / absence of the recording paper 1 is determined by the determination thresholds Ta and Tb that have just been stored.

On the other hand, when the recording paper 1 is not loaded when the recording process is started, the "paper out flag" is turned on, or the signal level La becomes equal to or lower than the threshold value Tb. To do. In such a case (“ON” in process 201 or N in process 202), an alarm is displayed on the operation display unit 11 (process 215) and the operation is stopped.

Further, for example, the recording paper 1 is the recording paper sensor S.
When the paper does not move due to a paper jam at the position of b, the recording paper sensor Sb detects the paper and the signal level Lb becomes the threshold value Tb.
Get bigger. In this case as well (N of 203), an alarm is similarly displayed (process 215). Also, during image recording,
When the recording paper 1 is torn, the recording paper sensor Sa no longer detects the paper and the signal level La becomes equal to or lower than the threshold value Ta.
In this case as well (N in step 205), an alarm is similarly displayed (step 215). Further, in the process 210, when the recording paper 1 is fed backward when the recording paper 1 is broken, the signal level Lb becomes higher than the threshold value Tb. In this case as well (N in process 211), an alarm is similarly displayed (process 215).
If the recording paper sensors Sa and Sb fail, the process 20
The signal levels La and Lb read and stored in 9 become equal to or less than a certain value. In this case as well (N in process 212), an alarm is similarly displayed (process 215).

By the way, the operation of feeding the recording paper 1 and cutting the leading end with the cutter 7 and returning the leading end to the fixed position P is called a paper cycle. In this embodiment, the operator can arbitrarily execute this paper cycle operation. When executing the paper cycle operation, the operator performs a predetermined activation operation on the operation display unit 11 as shown in FIG. 6 (process 301). When the image processing apparatus is activated, the processing 1 of FIG.
Each processing after 02 is similarly executed (processing 302). As a result, new threshold values Ta and Tb are set.

As described above, in the present embodiment, the detection signal level of the recording paper sensors Sa and Sb is read every time an image is recorded on one page, and the recording paper determination is performed based on the detection signal level. I am trying to reset the threshold value. As a result, due to the secular change of the recording paper sensors Sa and Sb,
Even if the detection signal level changes, the threshold value that follows the change is automatically set, so recording paper judgment errors can be prevented without using a special recording paper sensor with good characteristics. Like

Also, when the recording paper 1 is newly mounted, the threshold value is reset as in the above case. Thus, it is not necessary to set the initial value of the threshold value in advance in the apparatus, and even if the light reflectance of the newly attached recording paper 1 changes, the threshold value suitable for the recording paper 1 can be obtained. The value will be set correctly.

Further, when the detection result of the recording paper 1 is abnormal, an alarm is displayed so that the operator can easily know the occurrence of the abnormality. Further, in that case, since a new threshold value is not set, it is possible to prevent an improper threshold value from being set due to a temporary abnormality, and then becoming inoperable.

Further, the paper cycle operation can be arbitrarily executed by the manual operation of the operator, and the threshold value is automatically set at that time. Thereby, for example, when the recording operation is not executed for a long time, by executing the paper cycle operation once,
At that point, the correct threshold can be set again.

In the above embodiment, a new threshold value is set every time one page of an image is printed. However, it is set every time a plurality of pages are printed, or a printing operation is performed a plurality of times. It may be set to. For example,
When the threshold value is set for every n pages, as shown in FIG.
The detection signals a and Sb are read, and the respective signal levels La1, Lb1 to Lan, Lbn are stored in the memory 13. Then, when recording for n pages is completed,
From the signal level and the coefficient R, the threshold value T
a and Tb may be calculated as Ta = (La1 + La2 + ... Lan) .R / n Tb = (Lb1 + Lb2 + ... Lbn) .R / n. In this way, by setting the threshold value based on a plurality of signal levels, it is possible to set a highly reliable threshold value that is not affected by temporary condition changes such as fluctuations in the power supply voltage.

The threshold values Ta and Tb are calculated by multiplying the signal levels La and Lb of the detection detection signals of the recording paper sensors Sa and Sb by the coefficient R. When the signal level when Sb paper is detected is Lha and Lhb and the signal levels when it is not detected is Lla and Llb, the threshold values Ta and Tb are Ta = (Lha + Lla) / 2 Tb = (Lhb + Llb) / It may be calculated as 2. As a result, it is possible to accurately set the appropriate signal level.

Further, in the above embodiments, the case where the recording paper sensors Sa and Sb which are the reflection type optical sensors are used has been described, but the present invention can be applied to the case where the transmission type optical sensor is used. it can. In a transmissive optical sensor, a light emitting element and a light receiving element are arranged to face each other, the light receiving element detects incident light, an object is passed between the two, and at this time it is detected that the incident light is blocked. It is a thing. When a transmissive optical sensor is used in the image recording apparatus of FIG.
The recording paper 1 may be disposed between the light emitting element and the light receiving element.

Further, in the above-mentioned embodiments, the case where the roll paper is used as the recording paper has been described as an example, but the present invention can be similarly applied to the case where the so-called cut paper of a fixed size is used. . Furthermore, although a single image recording apparatus has been described as an example, it goes without saying that the same applies to an image recording unit of a facsimile machine or a copying machine.

[0041]

As described above, according to the present invention, when the image recording operation is executed, the detection signal level of the recording paper sensor is read and the threshold for recording paper determination is based on the detection signal level. Since the value is set again, even if the detection signal level changes due to aging of the recording paper sensor, the threshold value that follows the change is automatically set, so a special recording paper sensor with good characteristics can be used. Even without using, it is possible to prevent a recording paper determination error.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a mechanism of an image recording apparatus according to an embodiment of the present invention.

FIG. 2 is a block configuration diagram of an electronic circuit of the image recording apparatus.

FIG. 3 is a flowchart of an initial setting operation.

FIG. 4 is an operation flowchart showing a part of an image recording process.

FIG. 5 is an operation flowchart showing another part of the image recording process.

FIG. 6 is a flowchart of a paper cycle operation.

FIG. 7 is an explanatory diagram showing another embodiment of the threshold value setting method.

FIG. 8 is an explanatory diagram showing a detection signal of a recording paper sensor and a conventional problem.

[Explanation of symbols]

 1 recording paper 2 saucer 3 guide plate 4 thermal head 5 platen roller 7 cutter 8 device cover 9 image recording unit 10 A / D conversion unit 11 operation display unit 12 recording paper transport unit 13 memory 14 control unit SW cover switch Sa, Sb recording Paper sensor

Claims (6)

[Claims] 1. A recording paper feeding means for feeding a recording paper mounted in the apparatus, a recording means for recording an image on the recording paper fed, and a reflected light or a transmitted light for irradiating the recording paper with light. An image provided with a recording paper sensor for detecting light and a judging means for judging passage of each point of the recording paper based on a result of comparison between a detection signal level of light detected by the recording paper sensor and a constant threshold value. In a control method for a recording apparatus, a signal level reading means for reading a detection signal level of the recording paper sensor when executing an image recording operation, and a threshold for resetting the threshold value based on the read detection signal level. A method of controlling an image recording apparatus, comprising: a value updating unit, and automatically setting the threshold value that follows a change in a detection signal level of the recording paper sensor. 2. The method of controlling an image recording apparatus according to claim 1, wherein the threshold value is reset only when the recording paper has passed through the points correctly. 3. The image recording apparatus according to claim 1, wherein the threshold value is reset by reading the detection signal level of the recording paper sensor even when the recording paper is newly mounted. Control method. 4. The method of controlling an image recording apparatus according to claim 1, wherein an alarm is displayed when the read detection signal level indicates an abnormal value. 5. The image recording apparatus according to claim 1, further comprising operation means for reading a detection signal level of the recording paper sensor and arbitrarily performing an operation of resetting the threshold value. Control method. 6. The image according to claim 1, wherein the threshold value is reset based on an average value of the detection signal levels read each time the image recording operation is performed a predetermined number of times. Recording device control method.