JP2010069670A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To discriminate the front/rear and top/bottom of a regular sheet of paper. <P>SOLUTION: A recording head 12 is provided with a front face sensor (a front face light emitting element 14 and a front face light receiving element 16) for detecting a postal code number frame on the printed face side of a postcard by the recording head 12, and a rear face sensor (a rear face light emitting element 18 and a rear face light receiving element 20) for detecting a postal code number frame on the opposite face of the printed face by the recording head 12 is provided in a position facing the recording head 12. The front/rear and top/bottom of the postcard is determined by detecting the postal code number frame of the postcard. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a printing apparatus, and more particularly to a printing apparatus that performs printing on a standard sheet.

  In recent years, many printing apparatuses such as inkjet printers have been distributed, and printing can be easily performed at home. Since printing can be performed easily, addressing on a standard sheet such as a postcard or an envelope is printed using a printing apparatus.

  For example, greetings such as New Year's greetings, seasonal greetings, notifications of Keio matters, and notifications such as moving and moving are often printed on a large number of postcards, which can be easily done using the application software that comes with the personal computer. Can be printed.

  When printing postcards, the address is printed on the front side and the text is printed on the back side, but the position and color of the postal code frame are determined according to preset standards. In this case, it is necessary to accurately print the zip code in the frame.

  Further, when the front / back and top / bottom orientation of the postcard is not set correctly, the text is printed on the front surface where the address is to be printed, or the mail address is printed on the back surface where the text is printed.

Therefore, in the technique described in Patent Document 1, when printing on a standard sheet such as a postcard, a zip code frame is imaged by an image sensor attached to the head, and the image data and preset printing are recorded. It has been proposed to compare the conditions and determine whether the printing conditions for the standard paper are satisfied, and to continue printing or issue a warning according to the determination result.
JP 2001-121794 A

  However, in the technique described in Patent Document 1, since the presence / absence of a zip code frame is determined from the imaging result of the imaging element mounted on the head, the front and back of the postcard and the top / bottom direction of the surface can be determined. However, it is impossible to recognize the vertical direction of the back side where nothing is printed. Therefore, if the recording side is set to be the back side, no warning can be given even if the top and bottom are wrong.

  The present invention has been made in consideration of the above-described facts, and an object of the present invention is to make it possible to determine the front / back and top / bottom of a standard sheet.

  In order to achieve the above object, the invention described in claim 1 includes a first light receiving element that receives light that is irradiated from a first light emitting element that irradiates light on one surface of a standard paper and reflected by the standard paper. , A second light receiving element for receiving the light irradiated from the second light emitting element for irradiating the other surface of the standard paper and reflected by the standard paper, and each detection of the first light receiving element and the second light receiving element And determining means for determining the front and back and the top and bottom of the standard paper by detecting a predetermined standard printing portion of the standard paper based on the result.

  According to the first aspect of the present invention, the first light receiving element receives the light irradiated from the first light emitting element that irradiates light to one surface of the standard fixed paper and reflected by the standard paper, and the second light receiving element receives the second light. The light receiving element receives the light irradiated from the second light emitting element that irradiates the other surface of the standard paper and reflected by the standard paper. The first light emitting element and the first light receiving element may be provided in a head for printing an image on a standard sheet, for example, as in the invention described in claim 7.

  Then, the determination means determines the front and back and top and bottom of the standard paper by detecting a predetermined standard printing portion of the standard paper based on the detection results of the first light receiving element and the second light receiving element.

  Here, the standard paper has a predetermined standard printing portion, and the reflectance of light is reduced in the standard printing portion. That is, the determination unit can determine the front and back and the top and bottom of the standard paper by detecting the standard print portion from the detection results of the first light receiving element and the second light receiving element.

  In addition, as in the second aspect of the present invention, when the determination unit determines that the top and bottom are reversed, an image reversing unit that reverses the top and bottom of the image to be printed may be further provided. As a result, even when the top and bottom are reversed, it is possible to save the trouble of setting the standard paper again in the printing apparatus.

  Further, as in the third aspect of the invention, the front surface mode for printing the image corresponding to the front surface on the standard paper or the back surface mode for printing the image corresponding to the back surface on the standard paper according to the determination result of the determination means. You may make it further provide the selection means to select. As a result, even when the front and back sides are reversed, it is possible to save the trouble of setting the standard paper again in the printing apparatus.

  Further, as in the invention described in claim 4, the determination means calculates a period between peaks in each detection result of the first light receiving element and the second light receiving element, and the calculated period is a standard print portion of the standard paper. And determining the front and back and top and bottom of the standard paper based on the determination result of the determination means, or the first light receiving as in the invention according to claim 5. A determination means for calculating a period equal to or less than a predetermined threshold in each detection result of the element and the second light receiving element, and determining whether the calculated period is a regular printing portion of the standard paper; Based on this, the front and back and the top and bottom of the standard paper may be determined. At this time, in the case of further comprising a printing unit that ejects ink according to the image data and prints the image represented by the image data on the standard paper, the detection capability of the first light receiving element is reduced due to the mist of the ink. . Therefore, as in the invention described in claim 6, the determination means may further include a setting means for setting the threshold according to the image data at the previous printing.

  Further, for example, a postcard can be applied to the standard paper as described in claim 8, and a postal code frame can be applied as the standard printing portion. In this case, as in the invention described in claim 9, the determination means detects the zip code frame by the first light receiving element or the second light receiving element, and determines the light receiving element side where the zip code frame is detected as the surface. Thus, the front and back sides of the standard paper can be determined, and the destination postal code frame is detected by the first light receiving element or the second light receiving element, and the detected destination postal code frame with respect to the standard paper is detected. It becomes possible to determine the top and bottom based on the position. Further, as in the invention described in claim 11, the first light emitting element and the second light emitting element may be those that irradiate the standard paper with blue light. That is, since the postal code frame is red, detection accuracy can be improved by irradiating blue light.

  As described above, according to the present invention, there is an effect that the front and back and the top and bottom of the standard paper can be determined.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

(First embodiment)
1A and 1B are diagrams showing a schematic configuration of an ink jet printer according to a first embodiment of the present invention.

  The inkjet printer 10 according to the present embodiment is applied to a printer that prints a standard sheet as a printing target. As a standard form, a postcard will be described as an example.

  As shown in FIGS. 1A and 1B, the inkjet printer 10 according to the first embodiment of the present invention includes a recording head 12. The recording head 12 performs printing in the main scanning direction by ejecting ink while reciprocating along the rod 13 in the direction of the arrow in FIG. The sub-scan is performed by moving the postcard by the paper feed roller 15 or the like.

  Further, the postcard printed by the recording head 12 is discharged from the ink jet printer 10 by the paper feed roller 15 and placed on the guide plate 17.

  The recording head 12 of the inkjet printer 10 according to the present embodiment is provided with surface sensors (a surface light emitting element 14 and a surface light receiving element 16) for detecting a postal code frame on the printing surface side of the postcard by the recording head 12. Yes. The surface light emitting element 14 irradiates the printing surface of the postcard by the recording head 12 with light, and the surface light receiving element 16 receives light irradiated from the surface light emitting element 14 and reflected by the postcard.

  Further, a back surface sensor for detecting a postal code frame on the surface opposite to the printing surface by the recording head 12 at a position facing the recording head 12 (surface side opposite to the postcard surface detected by the surface sensor). (Back light emitting element 18 and back light receiving element 20) are provided. The back surface light emitting element 18 irradiates light on the surface opposite to the printing surface of the postcard by the recording head 12, and the back surface light receiving element 20 is irradiated from the back surface light emitting element and reflected by the postcard to receive light. The back sensor is provided at a position where the postal code frame of the postcard can be detected.

  The front surface light emitting element 14 and the back surface light emitting element 18 are preferably light sources that irradiate blue light on a postcard. Since the postal code frame of the postcard is red, detection accuracy can be improved by irradiating blue light.

  Here, detection of a postal code frame of a postcard will be described. FIGS. 2A and 2B are diagrams for explaining the detection of postal code frames of postcards by the surface light emitting element 14 and the surface light receiving element 16, and FIGS. 3A and 3B are backside light emission. It is a figure for demonstrating the detection of the postal code frame of a postcard by the element 18 and the back surface light receiving element 20, FIG. 4 (A) is a figure which shows an example of the luminance profile of the light received by the front surface light receiving element 16, FIG. 5B is a diagram illustrating an example of a luminance profile of light received by the back surface light receiving element 20.

  As shown in FIG. 2A, the postal code frame on the printing surface side by the recording head 12 is detected by moving the recording head 12 along the rod 13 in the direction of the arrow in FIG. The postcard 14 irradiates the postcard with light, and the surface light receiving element 16 receives reflected light from the postcard.

  That is, as shown in FIG. 2B, the surface light receiving element 16 receives light according to the reflectivity of the postcard along the main scanning direction, so that the amount of light in the postal code frame is smaller than in other positions. When the postal code frame is present, the surface light receiving element 16 can obtain a luminance profile as shown in FIG. Therefore, the zip code frame is detected by determining whether or not the cycle in which the amount of light is reduced is the cycle in the width direction of the zip code frame.

  On the other hand, as shown in FIG. 3 (A), the postal code frame on the surface opposite to the printed surface is detected from the back surface light emitting element 18 while moving the postcard in the sub-scanning direction (arrow direction in FIG. 3 (A)). The postcard is irradiated with light, and the back light receiving element 20 receives the reflected light from the postcard.

  That is, as shown in FIG. 3B, the back surface light receiving element 20 receives light according to the reflectance of the postcard along the sub-scanning direction, so that the amount of light in the postal code frame is lower than in other positions. When the postal code frame exists, the back light receiving element 20 can obtain a light profile as shown in FIG. Therefore, the postal code frame is detected by determining whether or not the period in which the light amount is reduced is the vertical direction of the postal code frame.

  Next, the configuration of the control system of the inkjet printer 10 according to the first embodiment of the present invention will be described. FIG. 5 is a block diagram showing the configuration of the control system of the inkjet printer 10 according to the first embodiment of the present invention.

  The inkjet printer 10 includes a control unit 22, and printing on a postcard is comprehensively controlled by the control unit 22.

  The control unit 22 is connected to a data receiving unit 24, a data storage unit 26, an image processing unit 28, a conveyance motor 30, a recording head 12, and the like. The control unit 22 controls these to print on a postcard or the like. Do.

  The data receiving unit 24 receives data to be printed from a personal computer or the like connected to the inkjet printer 10 and stores it in the data storage unit 26.

  The image processing unit 28 performs various types of image processing on the print target data stored in the data storage unit 26. As various image processing, for example, data conversion into a data format that can be processed by the inkjet printer 10 is performed.

  The conveyance motor 30 drives the paper feed roller 15 and the like to convey the postcard, and the recording head 12 performs printing on the postcard. Note that the recording head 12 in FIG. 5 includes a motor for moving the recording head 12 in the main scanning direction.

  Further, the control unit 22 is further connected with a front surface light emitting element 14, a front surface light receiving element 16, a back surface light emitting element 18, and a back surface light receiving element 20, and the front surface light emitting element 14 and the back surface light emitting element 18 are controlled by the control unit 22. As described above, the postal code frame of the postcard is detected by performing signal processing on the light reception results of the front surface light receiving element 16 and the back surface light receiving element 20 by the control unit 22. Specifically, a predetermined threshold value for the amount of light is stored in the control unit 22, a period of a portion that is equal to or less than the threshold value is obtained, and the control unit 22 determines whether or not the obtained period is a period in the postal code frame. By doing so, the postal code frame is detected.

  That is, the control unit 22 makes a front / back determination based on the presence / absence of a zip code. In the present embodiment, the surface on which the postal code frame is detected is determined as the front surface. In addition, when there is a sender postal code frame, the size of the postal code frame is different for the destination and the sender, so the control unit 22 determines the top and bottom from the position of the postal code with respect to the postcard. In the present embodiment, the top of the postcard is determined by determining whether the destination postal code frame has been detected first.

  By the way, the ink jet printer 10 performs printing by ejecting ink from the recording head 12. At this time, mist is generated between the recording head 12 and the postcard. When the mist is generated, the luminance profile detected by the surface light receiving element 16 is changed when the postal code frame is detected, and the postal code frame cannot be accurately detected.

  Therefore, in the present embodiment, the threshold for detecting the zip code is changed according to the amount of mist. Since the mist amount cannot be measured, in this embodiment, the mist amount is replaced with the image data amount, and the threshold value is changed according to the image data of the immediately preceding job.

  The threshold value is obtained by the luminance obtained from the light receiving element when the previous image data is solid-printed (point in FIG. 6b) and the luminance obtained from the light receiving element when the previous image data is a line drawing (point in FIG. 6a). The relationship is obtained, and a straight line with a threshold value which is always a lower value is obtained from the straight line passing through these two points. Then, a threshold value is set so that the period is always obtained by this threshold value.

  Specifically, before starting the print job, the brightness reflected at the destination postal code frame portion on the postcard surface when the image data at the previous printing is a line drawing is measured (point a in FIG. 6). Next, the amount of light (startup) reflected from the destination portion of the postcard surface when the image data at the previous printing is solid printing is measured (point in FIG. 6b). Then, a threshold straight line having a certain interval from the postcard surface luminance is obtained starting from point b.

  Next, processing performed by the control unit 22 of the inkjet printer 10 according to the first embodiment of the present invention configured as described above will be described. FIG. 7 is a flowchart showing an example of the flow of processing performed by the control unit 22 of the inkjet printer 10 according to the first embodiment of the present invention.

  When the start of printing is instructed, in step 100, the reading threshold value of the surface light receiving element 16 is set from the image data of the previous job, and the process proceeds to step 102. That is, the threshold value is set according to the image data of the previous job from the threshold line in FIG.

  In step 102, the transport motor 30 is driven so that the postcard is transported to the printing position and the process proceeds to step 104.

  In step 104, the postal code frame is read by the surface sensors (the surface light emitting element 14 and the surface light receiving element 16), and the process proceeds to step 106. That is, the recording head 12 is moved while irradiating light on the postcard from the surface light emitting element 14 and light is received by the surface light receiving element 16.

  In step 106, it is determined whether or not there is a luminance profile. If the determination is negative, the process proceeds to step 108. If the determination is affirmative, the process proceeds to step 110.

  In step 108, the process shifts to the back mode, and after the back mode is performed, the process is terminated. Details of the back mode will be described later.

  In step 110, the period is calculated and the routine proceeds to step 112. That is, in the luminance profile obtained by the surface light receiving element 16, the period of the portion below the set threshold is calculated.

  In step 112, it is determined whether or not the destination postal code frame has been detected first. If the determination is negative, the process proceeds to step 114. If the determination is negative, the process proceeds to step 116.

  In step 114, it is determined that the top / bottom of the postcard is reversed, and the top / bottom of the image data is reversed by reversing the top / bottom of the image data.

  In step 116, the conveyance motor 30 is driven to convey the postcard to the printing position, and the process proceeds to step 118.

  In step 118, a printing process based on the image data corresponding to the surface is performed, and the process proceeds to step 120. That is, the conveyance motor 30 and the recording head 12 are controlled to perform printing on the surface of the postcard.

  In step 120, it is determined whether or not printing is completed. If the determination is negative, the process returns to step 100 and the above-described processing is repeated. When the determination in step 120 is affirmed, the series of processing ends. .

  Here, the above-described back surface mode will be described in detail. FIG. 8 is a flowchart showing an example of the back surface mode processing flow in the inkjet printer 10 according to the first embodiment of the present invention.

  When the mode is shifted to the back side mode, in step 200, the transport motor 30 is driven, whereby the postcard is transported to the printing position and the process proceeds to step 202.

  In step 202, the postal code frame is read by the back surface sensors (the back surface light emitting element 18 and the back surface light receiving element 20), and the process proceeds to step 204. That is, the postcard is conveyed while irradiating the postcard from the backside light emitting element 18, and light is received by the backside light receiving element 20.

  In step 204, it is determined whether or not there is a luminance profile. If the determination is negative, the process proceeds to step 206. If the determination is affirmative, the process proceeds to step 208.

  In step 206, it is warned that it is not a postcard, and the routine proceeds to step 218. For example, a display indicating that it is not a postcard is performed on a monitor (not shown).

  On the other hand, in step 208, the period is calculated and the process proceeds to step 210. That is, in the luminance profile obtained by the back surface light receiving element 20, the period of the portion below the set threshold is calculated.

  In step 210, it is determined whether the destination postal code frame has been detected first. If the determination is negative, the process proceeds to step 212. If the determination is affirmative, the process proceeds to step 214.

  In step 212, it is determined that the top of the postcard has been reversed, and the top of the image data is reversed by reversing the top of the image data, and the flow proceeds to step 214.

  In step 214, the conveyance motor 30 is driven, whereby the postcard is conveyed to the printing position, and the process proceeds to step 216.

  In step 216, a printing process based on the image data corresponding to the back surface is performed, and the process proceeds to step 218. That is, the conveyance motor 30 and the recording head 12 are controlled to perform printing on the back surface of the postcard.

  In step 218, it is determined whether or not printing has been completed. If the determination is negative, the process returns to step 200 and the above-described processing is repeated. When the determination in step 218 is affirmed, the series of processing ends. .

  As described above, the inkjet printer 10 according to the present embodiment is provided with the front surface light emitting element 14 and the front surface light receiving element 16, and the back surface light emitting element 18 and the back surface light receiving element 20, and based on the detection result of each light receiving element. By detecting the fixed portion (postal code frame), the front and back of the postcard and the top and bottom can be determined. In addition, since only the front surface light emitting element 14, the front surface light receiving element 16, the back surface light emitting element 18, and the back surface light receiving element 20 are provided, an inexpensive apparatus can be obtained.

  In addition, in the inkjet printer 10, when detecting a zip code frame, detection becomes difficult due to mist, but in this embodiment, the zip code frame is detected according to the image data (mist amount) of the previous job. By changing the threshold value, the postal code frame can be detected accurately.

  Furthermore, since the zip code frame can be detected, the zip code can be reliably printed in the zip code frame during printing.

  In the first embodiment, since the luminance of the luminance profile obtained by the surface light receiving element 16 is reduced by the mist of ink ejected from the recording head, the threshold is set according to the image data. Alternatively, the bias voltage of the surface light receiving element 16 may be changed. That is, by increasing the bias voltage of the surface light receiving element 16 as the amount of mist increases, the signal level can be increased and the decrease in the luminance profile can be compensated, so that the zip code frame can be detected.

(Second Embodiment)
Next, an ink jet printer according to the second embodiment of the present invention will be described.

  In the first embodiment, the threshold for detecting the zip code frame is changed according to the amount of mist (image data of the previous job). However, in this embodiment, the front light receiving element 16 and the back light receiving element 20 A zip code frame is detected by detecting a peak in which the amount of light decreases from the detection result and calculating a period between the peaks. That is, only the processing performed by the control unit 22 is different, and the configuration of the ink jet printer 10 is the same as that of the first embodiment, and thus detailed description thereof is omitted.

  FIG. 9 is a flowchart illustrating an example of a flow of processing performed by the control unit of the inkjet printer according to the second embodiment of the present invention.

  In step 300, the postcard is transported to the printing position by driving the transport motor 30, and the process proceeds to step 302.

  In step 302, the postal code frame is read by the surface sensors (the surface light emitting element 14 and the surface light receiving element 16), and the process proceeds to step 304. That is, the recording head 12 is moved while irradiating light on the postcard from the surface light emitting element 14 and light is received by the surface light receiving element 16.

  In step 304, it is determined whether or not there is a luminance profile. If the determination is negative, the process proceeds to step 306, and if the determination is affirmative, the process proceeds to step 308.

  In step 306, the process proceeds to the back mode, and after the back mode is performed, the process is terminated. Details of the back mode will be described later.

  In step 308, the peak period is calculated, and the process proceeds to step 310. That is, in the luminance profile obtained by the surface light receiving element 16, a peak at which the amount of light decreases is obtained, and the period between the obtained peaks is calculated.

  In step 310, it is determined whether the destination postal code frame has been detected first. If the determination is negative, the process proceeds to step 312. If the determination is affirmative, the process proceeds to step 314.

  In step 312, it is determined that the top and bottom of the postcard is reversed, and the top and bottom of the image data is reversed, so that the top and bottom of the image is reversed, and the process proceeds to step 314.

  In step 314, the conveyance motor 30 is driven to convey the postcard to the printing position, and the process proceeds to step 316.

  In step 316, a printing process based on the image data corresponding to the surface is performed, and the process proceeds to step 318. That is, the conveyance motor 30 and the recording head 12 are controlled to perform printing on the surface of the postcard.

  In step 318, it is determined whether or not printing is completed. If the determination is negative, the process returns to step 300 and the above-described processing is repeated. When the determination in step 318 is affirmed, the series of processing ends. .

  Here, the above-described back surface mode will be described in detail. FIG. 10 is a flowchart showing an example of the back surface mode processing flow in the inkjet printer according to the second embodiment of the present invention.

  When the mode is shifted to the back surface mode, in step 400, the transport motor 30 is driven, whereby the postcard is transported to the printing position and the process proceeds to step 402.

  In step 402, the postal code frame is read by the back surface sensors (the back surface light emitting element 18 and the back surface light receiving element 20), and the process proceeds to step 404. That is, the postcard is conveyed while irradiating the postcard from the backside light emitting element 18, and light is received by the backside light receiving element 20.

  In step 404, it is determined whether or not there is a luminance profile. If the determination is negative, the process proceeds to step 406, and if the determination is affirmative, the process proceeds to step 408.

  In step 406, it is warned that it is not a postcard, and the routine proceeds to step 418. For example, a display indicating that it is not a postcard is performed on a monitor (not shown).

  On the other hand, in step 408, the period is calculated and the process proceeds to step 410. That is, in the luminance profile obtained by the back surface light receiving element 20, a peak at which the amount of light decreases is obtained, and a period between the obtained peaks is calculated.

  In step 410, it is determined whether the destination postal code frame has been detected first. If the determination is negative, the process proceeds to step 412. If the determination is affirmative, the process proceeds to step 414.

  In step 412, it is determined that the top and bottom of the postcard is reversed, and the top and bottom of the image data is reversed, so that the top and bottom of the image is reversed.

  In step 414, the conveyance motor 30 is driven to convey the postcard to the printing position, and the process proceeds to step 416.

  In step 416, a printing process based on the image data corresponding to the back surface is performed, and the process proceeds to step 418. That is, the conveyance motor 30 and the recording head 12 are controlled to perform printing on the back surface of the postcard.

  In step 418, it is determined whether or not printing is completed. If the determination is negative, the process returns to step 400 and the above-described processing is repeated. When the determination in step 418 is affirmed, the series of processing ends. .

  As described above, when detecting the zip code frame, even if the period between peaks in the light reception result of the surface light receiving element 16 is calculated, the zip code frame is detected as in the first embodiment. Can do. In addition, since the period between peaks is calculated, it is not necessary to change the threshold value as in the first embodiment even if mist occurs, so that the postal code frame can be detected more easily than in the first embodiment. .

  In each of the above embodiments, the zip code frame is detected by the front surface light emitting element 14, the front surface light receiving element 16, the back surface light emitting element 18, and the back surface light receiving element 20, but the present invention is not limited to this. The back sensor may be a line sensor, or the line sensor may be applied only to the back sensor.

  In each of the above embodiments, the ink jet printer has been described as an example. However, the present invention is not limited to this, and the front light emitting element 14, the front light receiving element 16, and the back light emitting element 18 are applied to a printer to which an electrophotographic method is applied. , And the back surface light receiving element 20 may be provided to determine the front and back and top and bottom of the standard paper.

FIG. 2A is a perspective view illustrating a schematic configuration of the inkjet printer according to the first embodiment of the present invention, and FIG. 3B is a side view illustrating the schematic configuration of the inkjet printer according to the first embodiment of the present invention. It is a figure for demonstrating the detection of the postal code frame of a postcard by a surface light emitting element and a surface light receiving element. It is a figure for demonstrating the detection of the postal code frame of a postcard by a back surface light emitting element and a back surface light receiving element. (A) is a figure which shows an example of the brightness | luminance profile detected by the surface light receiving element, (B) is a figure which shows an example of the brightness | luminance profile detected by the back surface light receiving element. It is a block diagram which shows the structure of the control system of the inkjet printer concerning 1st Embodiment of this invention. It is a figure which shows an example of the threshold value for detecting a postal code frame. It is a flowchart which shows an example of the flow of the process performed in the control part of the inkjet printer concerning 1st Embodiment of this invention. 3 is a flowchart illustrating an example of a back surface mode process flow in the inkjet printer according to the first embodiment of the present invention. It is a flowchart which shows an example of the flow of the process performed in the control part of the inkjet printer concerning 2nd Embodiment of this invention. It is a flowchart which shows an example of the flow of a process of the back surface mode in the inkjet printer concerning 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Inkjet printer 12 Recording head 14 Front surface light emitting element 16 Front surface light receiving element 18 Back surface light emitting element 20 Back surface light receiving element 22 Control part

Claims (11)

A first light receiving element for receiving light irradiated from a first light emitting element that irradiates light to one surface of the standard paper and reflected by the standard paper;
A second light receiving element for receiving the light emitted from the second light emitting element for irradiating the other surface of the standard paper and reflected by the standard paper;
Determination means for detecting the front and back and the top and bottom of the standard paper by detecting a predetermined standard printing portion of the standard paper based on each detection result of the first light receiving element and the second light receiving element;
Printing device with   The printing apparatus according to claim 1, further comprising an image reversing unit that reverses the top and bottom of an image to be printed when the determination unit determines that the top and bottom are reversed.   2. A selection means for selecting a front surface mode for printing an image corresponding to the front surface on a standard paper or a back surface mode for printing an image corresponding to the back surface on the standard paper according to a determination result of the determination means. Or the printing apparatus of Claim 2.   The determination means includes a determination means for calculating a period between peaks in each detection result of the first light receiving element and the second light receiving element, and determining whether the calculated period is the standard print portion, The printing apparatus according to claim 1, wherein the front and back and the top and bottom of the standard paper are determined based on a determination result of the determination unit.   The determination means calculates a period equal to or less than a predetermined threshold in each detection result of the first light receiving element and the second light receiving element, and determines whether the calculated period is the standard printing portion. 4. The printing apparatus according to claim 1, further comprising: determining the front and back and the top and bottom of the standard paper based on a determination result of the determination unit. A printing unit that discharges ink according to the image data and prints an image represented by the image data on a standard paper;
The printing apparatus according to claim 5, wherein the determination unit further includes a setting unit that sets the threshold according to image data at the time of previous printing.   The printing apparatus according to claim 1, wherein the first light emitting element and the first light receiving element are provided in a head for printing an image on a standard sheet.   The printing apparatus according to claim 1, wherein the standard paper is a postcard, and the standard printing portion is a postal code frame.   The printing apparatus according to claim 8, wherein the determination unit detects a zip code frame by the first light receiving element or the second light receiving element, and determines that the light receiving element side on which the zip code frame is detected is the front surface.   The determination unit detects a destination postal code frame by the first light receiving element or the second light receiving element, and determines the top and bottom based on a position of the detected destination postal code frame with respect to a standard sheet. The printing apparatus as described in.   The printing apparatus according to claim 9, wherein the first light emitting element and the second light emitting element irradiate blue light to the standard paper.

Images