JP6220686B2 - Image forming apparatus - Google Patents

Description

  Embodiments described herein relate generally to an image forming apparatus.

  An image forming apparatus that forms an image on a roll of continuous paper may need to form an image from a predetermined position on a recording medium.

  For example, a label which is a recording medium on which an image is formed by a label printer is affixed on a mount at a predetermined interval, and the label printer needs to form an image at a predetermined position on the label.

  Also, for example, a roll paper printer, which is an image forming apparatus installed in a bank ATM (automated teller machine), forms a predetermined content at a predetermined position on a preprinted recording medium. There is a need to.

  In the case of a label printer, the image forming apparatus includes a transmissive optical sensor, detects a portion where a label is not attached between the labels, and positions an image forming position.

  In the case of a roll paper printer, a black mark indicating an image forming position is printed on a recording medium in advance. The roll paper printer includes a reflection type optical sensor, detects a black mark, and positions an image forming position.

  Each of the transmission type optical sensor and the reflection type optical sensor includes a light emitting element that emits light and a light receiving element that receives the light.

  The light intensity of a light emitting element is weakened or increased with time. In addition, the sensitivity of the light receiving element may change due to changes over time.

  In these cases, the conventional image forming element cannot accurately position the printing position, and requires maintenance by a service person.

JP 2008-203899 A

  Therefore, there is a need for an image forming apparatus that can minimize the maintenance frequency even if the sensitivity of the optical sensor changes with time.

In order to solve the above-described problem, an image forming apparatus according to an embodiment includes an optical sensor including a light emitting unit and a light receiving unit, a head that forms an image on a roll-shaped recording medium, and a light detected by the light receiving unit. The first maximum threshold and the second maximum threshold indicating the range of the maximum intensity value, and the first minimum threshold and the second threshold indicating the range of the minimum value of the light intensity detected by the light receiving unit Image forming positions set between the minimum threshold value, the maximum threshold value range between the first maximum threshold value and the second maximum threshold value, and the minimum threshold value range between the first minimum threshold value and the second minimum threshold value. A storage unit for storing a determination threshold value and a plurality of maximum values for each image formation or a plurality of minimum values for each image formation of light intensity detected by the light receiving unit, and light detected by the light receiving unit And a control unit that discriminates the image forming position on the basis of the intensity and the discrimination threshold. The control unit stores the maximum or minimum value of the light intensity detected by the light receiving unit in the storage unit for each image formation, and a first average value that is an average of a plurality of maximum values stored in the storage unit or, calculating a second average value is an average of a plurality of minimum values stored in the storage unit, if the first average value is not in the maximum threshold range, or second average value is highest If not in the small threshold range, the discrimination threshold is adjusted.

1 is a diagram illustrating a configuration of an image forming apparatus. 1 is a block diagram illustrating a configuration of an image forming apparatus. 3 is a flowchart illustrating an operation of the image forming apparatus. It is a top view of a recording medium. FIG. 6 is a diagram illustrating a relationship between received light intensity and a discrimination threshold when the image forming apparatus detects a black mark. It is a figure which shows a mode when the illumination intensity of a 1st light emission part falls by a time-dependent change. It is a figure which shows a mode when the illumination intensity of a 1st light emission part rises with a time-dependent change.

  Hereinafter, an embodiment of an image forming apparatus will be described in detail with reference to the drawings.

  The image forming apparatus according to the present embodiment should take the maximum value of the light intensity detected by the light receiving unit, the optical sensor including the light emitting unit and the light receiving unit, the head that forms an image on a roll-shaped recording medium, and the light receiving unit. A first maximum threshold value and a second maximum threshold value indicating a range; a first minimum threshold value and a second minimum threshold value indicating a range to be taken as a minimum value of the light intensity detected by the light receiving unit; A storage unit for storing a determination threshold for determining detection of a black mark on a label or a recording medium, and a maximum value and a minimum value of light intensity detected by the light receiving unit each time one image is formed; The average value of the maximum value and the average value of the minimum value are calculated for each predetermined number of sheets, and the average of the maximum values is not between the first maximum threshold and the second maximum threshold, or the average of the minimum values is the first minimum A controller that adjusts the discrimination threshold when not in a range between the threshold and the second minimum threshold; Equipped with a.

  FIG. 1 is a diagram illustrating a configuration of the image forming apparatus 1. Hereinafter, the image forming apparatus 1 will be described using a label printer as an example.

  As shown in FIG. 1, the image forming apparatus 1 includes a reflective optical sensor 11 that detects a black mark printed in advance on a recording medium 10 wound in a roll shape, and a label that is attached to a mount 10 </ b> B of the recording medium 10. A transmissive optical sensor 12 for detecting a gap therebetween, a head 13 for forming an image on the label 10A, a platen 14 disposed opposite to the recording medium conveyance path between the head 13 and the label 10A from the mount 10B. And a peeling portion 15 to be provided.

  The reflective optical sensor 11 includes a first light emitting unit 11A that irradiates light, a first light receiving unit 11B that receives the light irradiated by the first light emitting unit 11A and reflected by the recording medium 10 and converts the light into an electrical signal, Is provided.

  The transmissive optical sensor 12 includes a second light emitting unit 12A that irradiates light, a second light receiving unit 12B that receives the light irradiated by the second light emitting unit 12A and transmitted through the recording medium 10 and converts the light into an electrical signal, Is provided.

  The image forming apparatus 1 detects the position of the label 10 </ b> A and the presence / absence of a label based on the output of the transmissive optical sensor 12, and determines the image formation start position based on the output of the reflective optical sensor 11.

  When the power is turned on, the image forming apparatus 1 determines whether or not the recording medium 10 has the label 10A. If it is determined that there is no label, the image forming apparatus 1 feeds the recording medium 10 until the label 10A is detected.

  When the label 10A is detected, the image forming apparatus 1 starts image formation from the place where the black mark is detected.

  The image-recorded recording medium 10 is conveyed to the peeling unit 15 where the label 10A is peeled and discharged.

  FIG. 2 is a block diagram illustrating a configuration of the image forming apparatus 1. As illustrated in FIG. 2, the image forming apparatus 1 includes a control unit 201 including a central processing unit (CPU) that is an arithmetic device, a storage unit 202 that stores information, and an image forming unit 203 that forms an image on a recording medium 10. And a drive unit 204 that drives a transport mechanism that transports the recording medium 10.

  The image forming apparatus 1 further includes a reflective photosensor 11 and a transmissive photosensor 12.

  The reflective optical sensor 11 includes a first light emitting unit 11A and a first light receiving unit 11B. The image forming apparatus 1 converts a digital signal that controls the light irradiation operation of the first light emitting unit 11A into an analog signal, and converts an optical signal received by the first light receiving unit 11B into a digital signal. A first A / D converter 206.

  The transmissive optical sensor 12 includes a second light emitting unit 12A and a second light receiving unit 12B. The image forming apparatus 1 converts the digital signal that controls the light irradiation operation of the second light emitting unit 12A into an analog signal, and converts the optical signal received by the second light receiving unit 12B into a digital signal. A second A / D converter 209.

  The storage unit 202 counts and stores the number of labels 10A formed with an image, a threshold storage unit 202B that stores a threshold value, and the light intensity detected by the first light receiving unit 11A and the second light receiving unit 12B. The maximum value storage unit 202C that stores the maximum value of each of the labels formed with an image, and the minimum value that stores the minimum value of the light intensity detected by the first light receiving unit 11A and the second light receiving unit 12B for each label formed with an image A value storage unit 202D.

  The threshold value stored in the threshold value storage unit 202B includes a first maximum threshold value and a second maximum threshold value indicating a range in which the maximum value of the light intensity detected by the first light receiving unit 11A and the second light receiving unit 12B is to be taken. The first light receiving unit 11A and the second light receiving unit 12B determine the detection of the label 10A or the black mark, and the first minimum threshold value and the second minimum threshold value indicating the range of the minimum value of the light intensity detected. Discriminating threshold value for performing the above.

  FIG. 3 is a flowchart showing the operation of the image forming apparatus 1. Hereinafter, a case where a black mark is detected by the reflective optical sensor 11 will be described.

  As shown in FIG. 3, in step 301, the image forming apparatus 1 acquires the maximum value after analog / digital of the received light intensity of the white portion.

  In step 302, the image forming apparatus 1 obtains the minimum value of analog / digital values of the light reception intensity of the black portion, that is, the black mark portion.

  In step 303, the image forming apparatus 1 determines whether the counter value exceeds a predetermined threshold number. When the image forming apparatus 1 determines that the counter value has exceeded the threshold number, the process proceeds to step 306, and when it is determined that the counter value has not exceeded, the process proceeds to step 304.

  In step 304, the image forming apparatus 1 stores the maximum value of the obtained analog / digital value of the received light intensity of the white portion.

  In step 305, the image forming apparatus 1 stores the minimum value of the analog / digital value of the received light intensity of the black portion, that is, the black mark portion.

  In step 306, the image forming apparatus 1 sums the stored maximum values of the received light intensity of the white portion after analog / digital, and divides this total value by the number of image formations, after analog / digital of the received light intensity of the white portion. The average value of the maximum values of is calculated.

  In step 307, the image forming apparatus 1 sums the stored analog values of the black portion, that is, the black mark portion, after analog / digital, and divides the total value by the number of image formations to divide the received light intensity of the black portion. The average value of the minimum values after analog / digital is calculated.

  In step 308, the image forming apparatus 1 determines that the average value of the calculated maximum values is within the range of the first maximum threshold value and the second maximum threshold value, and the calculated average value of the minimum values is the first minimum threshold value and the first minimum threshold value. It is determined whether it is within the range of the minimum threshold value of 2.

  In the image forming apparatus 1, the calculated average value of the maximum values is within the range of the first maximum threshold value and the second maximum threshold value, and the calculated average value of the minimum values is the first minimum threshold value and the second minimum threshold value. If it is determined that the average value is within the range, the process proceeds to step 311 where the calculated average value of the maximum values is within the range of the first maximum threshold value and the second maximum threshold value, and the calculated average value of the minimum values is the first value. If not determined to be within the range of the minimum threshold value and the second minimum threshold value, the process proceeds to step 309.

  In step 309, the image forming apparatus 1 adjusts the determination threshold value and adjusts the first maximum threshold value and the second maximum threshold value that are out of the range, or the first minimum threshold value and the second minimum threshold value.

  In step 310, the image forming apparatus 1 resets the counter.

  In step 311, the image forming apparatus 1 feeds the recording medium 10 to the image forming position.

  In step 312, the image forming apparatus 1 forms an image on the recording medium 10.

  In the case of the transmissive optical sensor 12, the white portion corresponds to the gap between the labels 10A in the above-described flowchart, that is, the portion where the label 10A is not attached to the mount 10B, and the black portion corresponds to the label 10A on the mount 10B. In addition to corresponding to the pasted portion, the image forming apparatus 1 performs the same operation as the flowchart shown in FIG.

  FIG. 4 is a plan view of the recording medium 10. As shown in FIG. 4, the recording medium 10 has a label 10A attached to the mount 10B with a gap 10C. The recording medium 10 is pre-printed with a black mark 10D indicating the image formation start position.

  FIG. 5 is a diagram illustrating the relationship between the received light intensity and the discrimination threshold when the image forming apparatus 1 detects the black mark 10D. The vertical axis represents received light intensity, and the horizontal axis represents time.

  As shown in the graph 501 in FIG. 5, the received light intensity decreases at the position of the black mark 10D. Here, at the time of initial setting, the image forming apparatus 1 sets the maximum threshold range, which is the range of the first maximum threshold value and the second maximum threshold value, so that the average of the maximum values of the white portions is included, and the first minimum threshold value is set. The minimum threshold range, which is the range of the threshold and the second minimum threshold, is set so that the average of the minimum values of the black portions is included.

  Further, the image forming apparatus 1 sets a discrimination threshold between the maximum threshold range and the minimum threshold range.

  Therefore, the image forming apparatus 1 can detect the black mark 10D.

  FIG. 6 is a diagram illustrating a state where the illuminance of the first light emitting unit 11A is decreased due to the change over time. As shown in the graph 601 in FIG. 6, the maximum value of the white portion decreases as the illuminance decreases.

  When the image forming apparatus 1 determines that the average of the maximum value of the white portion is lower than the maximum threshold range, the image forming apparatus 1 adjusts the maximum threshold range to include the average of the maximum value of the white portion, and additionally decreases the determination threshold. Let

  Therefore, the image forming apparatus 1 can detect the black mark 10D even if the illuminance of the first light emitting unit 11A decreases due to the change with time.

  FIG. 7 is a diagram illustrating a state where the illuminance of the first light emitting unit 11A is increased due to the change over time. As shown in the graph 701 in FIG. 7, the minimum value of the black portion increases as the illuminance increases.

  If the image forming apparatus 1 determines that the average of the minimum value of the black portion has risen above the minimum threshold range, the image forming apparatus 1 adjusts the minimum threshold range to include the average of the minimum value of the black portion, and additionally increases the determination threshold value. Let

  Therefore, the image forming apparatus 1 can detect the black mark 10D even if the illuminance of the first light emitting unit 11A increases due to a change with time.

  In the case of the transmissive optical sensor 12, only the first light emitting portion 11A is changed to the second light emitting portion 12A, the black mark 10D as a black portion is changed to the label 10A, and the white portion is changed to the gap 10C. The device 1 performs the same operation as described above.

  As described above, the image forming apparatus 1 according to this embodiment includes the optical sensor including the light emitting unit and the light receiving unit, the head 13 that forms an image on the recording medium, and the maximum light intensity detected by the light receiving unit. A first maximum threshold and a second maximum threshold indicating a range to be taken, a first minimum threshold and a second minimum threshold showing a range to be taken of a minimum value of the light intensity detected by the light receiving unit, and a label A storage unit for storing a discrimination threshold for determining detection of 10A or black mark 10D, and a maximum value and a minimum value of light intensity detected by the light receiving unit each time one image is formed, and a predetermined number of sheets The average value of the maximum value and the average value of the minimum value stored in the storage unit are calculated every time, and the average of the maximum value is not between the first maximum threshold value and the second maximum threshold value. Is not within the range of the first minimum threshold and the second minimum threshold, the discrimination threshold And a control unit for adjusting.

  Therefore, there is an effect that the maintenance frequency can be minimized even if the sensitivity of the optical sensor changes with time.

  Although several embodiments have been described, these embodiments have been presented by way of example and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are also included in the invention described in the claims and the equivalents thereof.

1: Image forming apparatus 11: Reflection type optical sensor 12: Transmission type optical sensor 13: Head 14: Platen

Claims (6)

An optical sensor comprising a light emitting part and a light receiving part;
A head for forming an image on a roll-shaped recording medium;
A first maximum threshold value and a second maximum threshold value indicating a range where the maximum value of the light intensity detected by the light receiving unit should be taken, and a range where the minimum value of the light intensity detected by the light receiving unit should be set. Between the first minimum threshold and the second minimum threshold, the maximum threshold range between the first maximum threshold and the second maximum threshold, and between the first minimum threshold and the second minimum threshold. Discrimination threshold for determining the image forming position set between the minimum threshold range and a plurality of maximum values for each image formation of the light intensity detected by the light receiving unit or a plurality of minimums for each image formation A storage unit for storing values,
A control unit that determines the image forming position based on the intensity of light detected by the light receiving unit and the determination threshold,
The controller is
Storing the maximum value or the minimum value of the light intensity detected by the light receiving unit in the storage unit for each image formation;
A first average value that is an average of the plurality of maximum values stored in the storage unit or a second average value that is an average of the plurality of minimum values stored in the storage unit is calculated. ,
If the first average value is not preceded Symbol maximum threshold range, or, if the second average value is not in the prior SL minimum threshold range, adjusting the determination threshold value,
Image forming apparatus. The recording medium is a label mount on which a plurality of labels are attached in the longitudinal direction at intervals,
The optical sensor is a transmissive optical sensor in which the light receiving unit detects light from the light emitting unit that has passed through the recording medium.
The control unit detects a gap between labels based on the intensity of light detected by the light receiving unit and the determination threshold, and determines the image forming position based on the detection result.
The image forming apparatus according to claim 1. The controller is
3. The image forming apparatus according to claim 2, wherein, when the first average value falls below the maximum threshold range, the maximum threshold range is adjusted so that the first average value is included, and the determination threshold is lowered. . The recording medium is a continuous paper on which black marks are repeatedly recorded in the longitudinal direction,
The optical sensor is a reflective optical sensor in which the light receiving unit detects the light of the light emitting unit reflected by the surface of the recording medium,
The control unit detects the black mark based on the intensity of light detected by the light receiving unit and the determination threshold, and determines the image forming position based on the detection result.
The image forming apparatus according to claim 1. The controller is
When the first average value falls below the maximum threshold range, the maximum threshold range is adjusted so that the first average value is included, and the determination threshold value is lowered.
The image forming apparatus according to claim 4. The controller is
When the second average value exceeds the minimum threshold range, the minimum threshold range is adjusted so that the second average value is included, and the determination threshold is increased.
The image forming apparatus according to claim 1.

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