JP2006198833A - Printer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a printer capable of detecting an end part of a recording medium and a mark for adjusting a printing position by one position-detecting means and capable of preventing a recording unit from erroneously printing an image or the like by controlling a time for detecting a marker. <P>SOLUTION: The printer is equipped with a carrying unit, a first recording unit printing at least a mark 11m, a recording unit arranged on the downstream side more than the first recording unit, a position-detecting means emitting a light with a complementary color of the mark 11m, a comparing means comparing an inputting signal obtained from the position-detecting means with a reference voltage and outputting an outputting signal OS, and a controlling unit for controlling the first recording unit and other recording units based on the outputting signal OS. The comparing means is formed so that a first reference voltage for detecting the end part E of the recording medium 2 and a second reference voltage for detecting the mark 11m can be freely selected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a printer that prints a plurality of colored images such as color photographic images, and in particular, a plurality of recording units that print various color inks are provided along the conveyance direction of a recording medium. The present invention relates to a printer suitably used for a tandem printer or the like.

  Conventionally, a tandem printer having a plurality of color ink ribbons has been used as one means for printing a color image or the like on a recording medium such as recording paper.

  As an example, the tandem printer (hereinafter simply referred to as “printer”) 101 includes a plurality of recording units 111, 112, 113, having ink ribbons 111a, 112a, 113a, 114a, as shown in FIG. 114 and transport units 121, 122, 123, and 124 that transport the recording medium 102. The ink ribbons 111 a, 112 a, 113 a, 114 a disposed in the recording units 111, 112, 113, 114 are cyan (C), magenta (M), yellow (Y), or Any one color of black (K), which is the most used color, is applied on the surface to form a strip shape. The recording units 111, 112, 113, and 114 thermally transfer the ink ribbons 111a, 112a, 113a, and 114a having any one of the colors described above and the inks of the ink ribbons 111a, 112a, 113a, and 114a. Thermal heads 111b, 112b, 113b, 114b are provided. The printer 101 is provided with the ink ribbons 111 a, 112 a, 113 a, and 114 a arranged in the recording units 111, 112, 113, and 114 with different colors. The plurality of recording units 111, 112, 113, 114 are sequentially arranged along the conveyance direction of the recording medium 102, and are passed through the ink ribbons 111 a, 112 a, 113 a, 114 a mounted inside. It is disposed at a position where it abuts on the recording medium 102. The recording units 111, 112, 113, 114 are referred to as a first recording unit 111, a second recording unit 112, a third recording unit 113, a fourth recording unit 114 from the most upstream side in the conveyance direction of the recording medium 102. To do.

  Each of the recording units 111, 112, 113, 114 is transported to the position facing the thermal heads 111b, 112b, 113b, 114b via the ink ribbons 111a, 112a, 113a, 114a and the recording medium 102, respectively. Platen rollers 121b, 122b, 123b, and 124b included in the units 121, 122, 123, and 124 are provided. Further, on the downstream side with respect to the conveying direction, cylindrical feed rollers 121a, 122a, 123a, and 124a are arranged to face each other.

  In the printer 101 formed as described above, when the recording start position of the recording medium 102 reaches a position facing the first recording unit 111, the thermal head 111b provided in the first recording unit 111 presses the platen roller 121b. To do. Specifically, the thermal head 111b included in the first recording unit 111 is headed down to the first platen roller 121b facing the first recording unit 111, or the first platen roller 121b is moved to the first recording unit 111 side. Let me up. Then, the thermal head 111b of the first recording unit 111 and the first platen roller 121b are brought into pressure contact with each other via the recording medium 102 and the ink ribbon 111a. Yellow) ink is transferred.

  Subsequently, when the recording start position reaches a position facing the second recording unit 112, the thermal head 112 b included in the second recording unit 112 is headed down, or the second platen roller facing the second recording unit 112. 122b is raised. Then, the thermal head 112b of the second recording unit 112 and the second platen roller 122b are brought into pressure contact with each other via the recording medium 102 and the ink ribbon 112a, so that the second recording unit 112 causes M (magenta) from above the Y ink. The ink is transferred.

  In this manner, the ink is transferred to the recording medium 102 to be printed by sequentially heading down from the upstream recording unit in the conveyance direction of the recording medium 102 or by sequentially raising the upstream platen roller. A desired color image was printed by applying a plurality of inks on the recording medium 102 (see Patent Document 1).

  In order to perform the above-described series of operations accurately, the print start positions of the images of the respective colors to be printed must be the same in any recording unit 111, 112, 113, 114. In order to match the print start positions of images printed by the recording units 111, 112, 113, and 114, generally, the number of steps of the motors disposed in the transport units 121, 122, 123, and 124 is recorded. The control unit 150 controls the medium transport amount. However, in this method, when the conveyance amount of the recording medium 102 is shifted during the conveyance due to the deflection of the recording medium or the like, the print start position of the image may be different for each recording unit 111, 112, 113, 114. there were.

  Therefore, conventionally, a registration mark 104 for alignment is attached to the recording medium 102 in advance, and each recording medium 102 to which the registration mark 104 is attached is detected by a CCD camera 103 or the like that detects the registration mark 104. The print start position of the image printed by the recording units 111, 112, 113, and 114 has been adjusted (see Patent Document 2).

  In addition to the position detection means for detecting the registration marks, there are printers that are separately provided with position detection means for detecting the edge of the recording medium.

JP 2000-263864 A JP 2002-86876 A

  However, if the registration mark 104 for positioning is not printed on the recording medium 102 to be printed, it is naturally impossible to detect the position information of the recording medium 102, and thus the printing position cannot be adjusted. There was a problem that there was.

  Further, even when the registration mark 104 for positioning is printed on the recording medium 102 to be printed, in order to accurately detect the intersecting portion of the cross-shaped registration mark 104 formed by extremely thin lines, The position detection means such as the CCD camera 103 that detects the cross-shaped registration marks 104 is required to have extremely high position detection accuracy, and accordingly, the manufacturing cost of the printer 101 having the position detection function increases. There was a problem.

  Further, since the conventional printer cannot detect the edge of the recording medium and the registration mark as the position adjustment mark by one position detecting means, the position detecting means for detecting the edge of the recording medium, and the position adjustment It is necessary to separately provide position detecting means for detecting the register marks for use. For this reason, the number of position detection means is increased, which increases the manufacturing cost of the printer.

  Accordingly, the present invention has been made in view of the above-described points, and an object of the present invention is to provide a printer capable of detecting an end portion of a recording medium and a print position adjustment mark by a single position detection unit. It is to be.

  Another object of the present invention is to provide a printer that can prevent the recording unit from printing an image or the like by controlling the marker detection time.

  In order to achieve the above-described object, a printer according to the present invention includes, as a first aspect, a transport unit that transports a recording medium, a first recording unit that prints at least a mark on the transported recording medium, A recording unit that prints at least one image disposed downstream of the first recording unit in the transport direction, a position detection unit that emits complementary color light of the mark, and the position detection unit. Comparing means for comparing the voltage of the input signal with a reference voltage and outputting an output signal, and a control unit for controlling the first recording unit and the other recording units based on the output signal.

  In the printer of the present invention, as a first aspect, the comparison means in the printer of the present invention has a first reference voltage for detecting the end of the recording medium and a first reference voltage for detecting the mark. Two reference voltages are selectable.

  According to a second aspect of the printer of the present invention, the second reference voltage in the printer of the first aspect is a voltage of an electric signal in a state where the position detection means recognizes the recording medium and the first reference voltage. It is set to a value in between.

  According to a third aspect of the printer of the present invention, the control unit in the printer of the first or second aspect outputs the time until the time required for image printing elapses after the position detection means finishes detecting the mark. The control based on the signal OS is not performed.

  Since the printer of the present invention is formed as described above, it has two functions: a function for detecting an end of a recording medium on which an image or the like is printed and a function for detecting a print position adjustment mark printed on the recording medium. One function can be performed by one position detecting means, and the production cost can be reduced.

  Also, the printer of the present invention prevents printing due to erroneous control of the recording unit by appropriately setting two types of reference voltages or not performing a control performed based on the detection result of the position detection means for a certain period. It becomes possible.

  That is, since the image of each color component is printed at a desired position by the printer of the present invention, there is an effect that the print quality of the image printed on the recording medium is improved.

  Hereinafter, embodiments of the printer of the present invention will be described with reference to FIGS. 1 to 3. 1 is a side view showing an embodiment of the printer of the present invention, FIG. 2 is a circuit diagram of comparison means in the printer of the present invention, and FIG. 3 is a conceptual diagram showing a detection method of position detection means in the printer of the present invention. It has become.

  First, each member provided in the printer of this embodiment will be described.

  For example, as shown in FIG. 1, the printer 1 according to the embodiment of the present invention includes recording units 11, 12, 13, and 14 that print based on each color component included in image data, and a transport unit 21 that transports a recording medium 2. , 22, 23, 24, position detection means 32, 33, 34 for detecting the alignment mark 11m (see FIG. 3), and a control unit 50 for controlling the printing of each recording unit 11, 12, 13, 14 have.

  Each recording unit 11, 12, 13, 14 disposed in the printer 1 of the present embodiment records each ink ribbon 11a, 12a, 13a, 14a to which ink of a specific color is applied and the ink. Each of the thermal heads 11b, 12b, 13b, and 14b that thermally transfer to the medium 2 is formed. Each of the recording units 11, 12, 13, and 14 is arranged in order along the conveyance direction FD of the recording medium 2, and each of the four recording units 11, 12, 13, and 14 is YMCK ( Each of the ink ribbons 11a, 12a, 13a, which is any one color of yellow, magenta, cyan, and black) and applied with a color different from the color of the ink of each of the other recording units 11, 12, 13, and 14. 14a. In the present embodiment, the ink colors of the ink ribbons 11 a, 12 a, 13 a, and 14 a arranged in the recording units 11, 12, 13, and 14 are upstream (with respect to the conveyance direction FD of the recording medium 2). They are arranged in the order of Y, M, C, K from the left side in FIG. In the following, the names of these recording units 11, 12, 13, and 14 are named in order from the upstream side with respect to the conveyance direction FD of the recording medium 2, in order from the first recording unit 11, the second recording unit 12, and the third recording unit 13. The fourth recording unit 14 is assumed. Further, the image printed by the first recording unit 11 is set as the first color image 11p, and the second color image 12p, the third color image 13p, and the fourth color image are similarly applied to the second recording unit 12 and thereafter. 14p. The order of colors applied to the ink ribbons 11a, 12a, 13a, and 14a disposed in the recording units 11, 12, 13, and 14 is not limited to the order of Y, M, C, and K. good. Further, at least one recording unit may be provided on the downstream side of the first recording unit 11 as in the case of performing two-color printing.

  Each transport unit 21, 22, 23, 24 arranged adjacent to each of the recording units 11, 12, 13, 14 includes at least a platen roller 21b, 22b, 23b, 24b, a feed roller 21a, 22a, 23a, 24a.

  The platen rollers 21b, 22b, 23b, and 24b are disposed below the thermal heads 11b, 12b, 13b, and 14b disposed in the adjacent recording units 11, 12, 13, and 14, respectively. The platen rollers 21b, 22b, 23b, and 24b are formed in a cylindrical shape or a columnar shape.

  A plurality of feed rollers 21a, 22a, 23a, and 24a are arranged on the downstream side of the recording units 11, 12, 13, and 14 with respect to the transport direction FD, and the feed rollers 21a, 22a, 23a, and 24a The shape is formed in a cylindrical shape or a columnar shape. A plurality of these feed rollers 21 a, 22 a, 23 a, 24 a are arranged in the printer 1 of this embodiment, and the plurality of feed rollers 21 a, 22 a, 23 a, 24 a are sandwiched from the front and back of the recording medium 2. Are disposed so as to have a positional relationship that allows them to be conveyed.

  The platen rollers 21b, 22b, 23b, 24b and the feed rollers 21a, 22a, 23a, 24a described above are arranged so that their central axes are perpendicular to the conveyance direction FD of the recording medium 2, It is attached so that it can rotate around the central axis of the. Further, the feed rollers 21a, 22a, 23a, 24a described above are formed to be rotationally driven by a motor (not shown).

  Each of the transport units 21, 22, 23, and 24 in the present embodiment described above is disposed adjacent to the downstream side of each of the recording units 11, 12, 13, and 14, and therefore, in the following, each of the transport units. The names 21, 22, 23, and 24 are named in order from the upstream side with respect to the conveyance direction FD of the recording medium 2, from the first conveyance unit 21, the second conveyance unit 22, the third conveyance unit 23, and the fourth conveyance unit 24, respectively. To do.

  As shown in FIG. 1, each of the position detection means 31, 32, 33, 34 is attached adjacent to the downstream side of the first to fourth recording units 12, 13, 14. The position detection means 31, 32, 33, and 34 are formed to include light emitting elements 31a, 32a, 33a, and 34a and light receiving elements 31b, 32b, 33b, and 34b. The light emitting elements 31a, 32a, 33a, and 34a are LEDs (light emitting diodes) that emit complementary colors of colors applied by the first recording unit 11 (in the present embodiment, blue is the complementary color of Y (yellow)). ) Is used. As the light receiving elements 31b, 32b, 33b, and 34b, general-purpose phototransistors conventionally used are used. In the following, the names of the position detection means 31, 32, 33, and 34 correspond to the names of the recording units 11, 12, 13, and 14, respectively, so that the first position detection means 31, the second position detection means 32, The third position detector 33 and the fourth position detector 34 are used.

  Each position detection means 31, 32, 33, 34 is disposed at a position below which the alignment mark 11m is conveyed. Further, the distance d from each position detection means 31, 32, 33, 34 to the recording medium 2 is set according to the detection function of each position detection means 31, 32, 33, 34 used. For example, in the present embodiment, the distance d from the position detection means 32, 33, 34 to the recording medium 2 is set to about 8 mm.

  Between each position detection means 31, 32, 33, 34 and the control unit 50, as shown in FIG. 2, based on the threshold value TH obtained by selecting two kinds of threshold values TH1, TH2. Comparing means 32c for judging the magnitude relationship of the input signal IS and outputting an H level or L level output signal is provided. The comparator 32c of this embodiment uses a comparator.

  One input terminal of the comparison means 32c is connected to the light receiving element 32b of each of the position detection means 31, 32, 33, 34, and the other input terminal is connected to two kinds of reference voltages by the switching means 60. Any one of the power supplies rf1 and rf2 is selected and connected. Further, the output terminal of the comparison means 32 c is connected to the control unit 50.

  The power supplies rf1 and rf2 serving as reference voltages determine the first threshold value TH1 and the second threshold value TH2 used for the comparison means. The first threshold value TH1 is set to an intermediate value of 2.5V because the voltage range of the input signal is 0 to 5V. The second threshold value TH2 is between 0 and 2.5V, and is set according to the detection capability of each position detection means 31, 32, 33, 34. For example, when the detection speed of the position detector is slow, the value of the second threshold value TH2 is set to a value close to 0V.

  A switching means 60 is disposed between the power supplies rf1 and rf2 serving as the two types of reference voltages and the comparison means 32c. The switching means 60 is timed or condition controlled by the control unit 50. When the switching means 60 is timed, the position detection means 31, 32, 33, 34 performs control such that the position detection means 31, 32, 33, 34 switches after a predetermined time has elapsed after detecting the end E or the mark 11m of the recording medium 2. In addition, when the switching means 60 is subjected to condition control, control is performed such that the switching is performed when the value of the second threshold value TH2 or higher is changed to a value of the second threshold value TH2 or lower. Since these controls are set according to the use conditions in the printer 1 of the present embodiment, it is preferable to make appropriate changes in printers having different use conditions.

The control unit 50 is connected to the recording units 11, 12, 13, 14, the transport units 21, 22, 23, 24 and the position detection means 31, 32, 33, 34. The control unit 50 controls the print position based on the print information recorded in the recording unit in the control unit 50. As shown in FIGS. 3 and 4, this recording unit is based on the end E of the recording medium 2.
(A) Print start position of mark 11m,
(B) Print end position of mark 11m,
(C) Print start position of the first color image 11p (D) Print end position of the first color image 11p (D2) The second recording unit detects the mark 11m and then the second recording unit detects the second color. Transport amount until the start of image printing,
(D3) A conveyance amount from when the third position detecting unit detects the mark 11m to when the third recording unit starts printing an image of the third color, and (D4) the fourth position detecting unit detects the mark 11m. Then, printing information relating to the conveyance amount from when the fourth recording unit starts printing the fourth color image is recorded in advance. These pieces of print information are measured in advance using a prototype of the printer 1 of the present embodiment. Further, the transport amounts D2, D3, and D4 are (the print start position C ′ of each image from the distance to the detection position of the mark 11m) − (from each position detection unit 32, 33, and 34 to each recording unit 12, 13, (Distance up to 14). Note that the respective carry amounts D2, D3, and D4 are set individually because arrangement errors of the position detection units 32, 33, and 34 are taken into consideration.

In addition, the recording unit can record the detection start position of the (A ′) mark 11m and the detection end position of the (B ′) mark 11m detected by the position detection units 32, 33, and 34. ing.

  The length from the end of the recording medium 2 to the print start position A of the mark 11m, the length from the print start position A of the mark 11m to the print end position B of the mark 11m, and the first color from the print end position B of the mark 11m The position of the image 11p to the print start position C is determined by the print start position A of the mark 11m, the print end position B of the mark 11m, and the printing of the first color image 11p. The length is set in advance so that the start position C can be reliably recognized without being misidentified.

  Next, the operation of the printer of this embodiment will be described with reference to FIGS. 1 and 3.

  As shown in FIG. 1, the recording medium 2 on which an image is printed is conveyed from the left side to the right side in the conveyance direction FD by the conveyance units 21, 22, 23, and 24 of the printer 1 of this embodiment. Direction). When the end E of the recording medium 2 arrives below the first position detecting means 31 (at time T0 in FIG. 3), the first position detecting means 31 detects the end E of the recording medium 2. The first position detector 31 outputs the power supply voltage 5V as the input signal IS at T0, and thereafter, as the recording medium 2 is transported, the input signal IS gradually decreases as shown in FIG. When this input signal IS falls below the first threshold value TH1 (at time T1 in FIG. 3), the comparison means 32c connected to the first position detection means 31 is connected to the power source rf1 by the switching means 60. Since the first threshold value TH1 is selected, the output signal OS from the L level to the H level is output. Since the first threshold value TH1 is set in the vicinity of 2.5V that is an intermediate value from 0 to 5V, it is possible to appropriately distinguish the presence or absence of the recording medium 2. When the H level output signal OS is output to the control unit 50, the control unit 50 recognizes the end E of the recording medium 2.

  When the first position detecting unit 31 detects the end E of the recording medium 2, the printing start position A of the mark 11m arrives below the first recording unit 11 by conveying the recording medium 2 by a certain amount (FIG. 3). The first recording unit 11 starts printing the Y (yellow) mark 11m on the recording medium 2 at time T4 in FIG. When the mark printing end position B reaches below the first recording unit 11 (T6 in FIG. 3), the first recording unit 11 finishes printing the mark 11m. After that, when the recording medium 2 is conveyed by a certain amount, when the printing start position C of the first color image 11p reaches the lower side of the first recording unit 11 (at time T9 in FIG. 3), the first recording unit 11 When printing of the first color image 11p is started on the recording medium 2 and the print end position D of the first color image 11p reaches below the first recording unit 11 (T10 in FIG. 3), the first recording unit 11 finishes printing the first color image 11p.

  Next, when the end E of the recording medium 2 is conveyed below the second position detection means 32 (at time T0 in FIG. 3), it is obtained from the second position detection means 32 as shown in FIG. The input signal IS changes from 5V to 0V, but when the input signal IS falls below the first threshold value TH1 (at time T1 in FIG. 3), the comparison means 32c connected to the first position detection means 31 Since the power source rf1 is connected by the switching means 60 and compared with the first threshold value TH1 as a reference, the output signal OS switched from the L level to the H level is output (at time T1 in FIG. 3). When the recording medium 2 is further conveyed, the mark 11m printed on the recording medium 2 is conveyed below the second position detecting means 32 (at time T4 in FIG. 3). Since the complementary color light L (blue light in this embodiment) emitted by the second position detecting means 32 is absorbed by the Y (yellow) mark 11m, an electric signal (comparison) obtained from the second position detecting means 32 is used. The voltage of the input signal IS) in the means 32c changes in a direction rising from 0V (from T4 to T6 in FIG. 3).

  During this time, when the input signal IS rises above the second threshold value TH2 set to a value between 0V and TH1 (at time T5 in FIG. 3), the power source rf2 is connected by the switching means 60, and the second threshold value is set. Since the comparison is performed using TH2 as a reference, as shown in FIG. 3, the comparison unit 32c outputs an output signal OS switched from the H level to the L level. That is, since the comparison unit 32c sets the second threshold value TH2 to a value lower than 2.5V that is the value of the first threshold value TH1, the input signal IS by detection of the mark 11m is 2.5V. The output signal OS can be changed from the H level to the L level even when the value is not larger than the above value. Further, the comparison means 32c sets the second threshold value TH2 in accordance with the width dimension of the mark 11m to be detected (the length of the mark 11m in the transport direction), so that the output signal OS can be transmitted without misidentification to the control unit 50. It is possible to output to.

  When the mark 11m passes below the second position detection means 32 and the voltage of the input signal IS is lower than the voltage of the second threshold value TH2 (at time T7 in FIG. 3), the output signal OS is at L level. The second position detector 32 ends the detection of the mark 11m. Thereafter, the input signal IS gradually decreases to 0 V (at time T8 in FIG. 3). Then, when the mark 11m is detected by the second position detection means 32, as shown in FIG. 4, each of the transport units 21, 22, 23, and 24 is recorded on the downstream side by a preset transport amount D2. 2 is transported.

  When the mark 11m is detected and the recording medium 2 is transported by the transport amount D2, the print start position C ′ of the second color image 12p arrives below the second recording unit 12. Then, the second recording unit 12 starts printing the second color image 12p formed by M (magenta) from the print start position C 'of the second color image 12p.

  Here, when the second position detection unit 32 finishes detecting the mark 11m, the second recording is performed even if the level of the output signal OS changes by detecting the first color image 11p of the same color as the Y mark 11m. In order not to send a print instruction to the unit 12 or a conveyance command to the conveyance units 21, 22, 23, 24, the control unit 50 starts from the time when the second position detection unit 32 finishes detecting the mark 11m. Until the second recording unit 12 finishes printing the second color image 12p, no instruction for printing or conveyance is given. That is, since the control unit 50 is set to the period during which the control based on the output signal OS is not performed, the first color image 11p is not mistaken as the mark 11m.

  The third color image 13p and the fourth color image 14p are also printed in the same manner as the second color image 12p described above, so that there is no deviation from the print area of the first color image 11p. Printing can be performed in accordance with the first color image 11p.

  That is, the printer 1 of the present embodiment completely matches the print start positions C or C ′ of the first color image 11p, the second color image 12p, the third color image 13p, and the fourth color image 13p. Therefore, it is possible to print a high-quality image with no printing position shift.

  In addition, this invention is not limited to embodiment mentioned above etc., A various change is possible as needed. For example, in the present embodiment, the mark 11m printed on the recording medium 2 is printed in front of the first color image 11p, but corresponds to the arrangement positions of the position detection means 32, 33, and 34. By changing from the downstream side to the upstream side of each recording unit 12, 13, 14 except for the first recording unit 11, the position of the mark 11m to be printed is formed and detected behind the first color image 11p. It becomes possible.

The side view which shows an example of embodiment in the printer of this invention Circuit diagram of comparison means in printer of the present invention Schematic diagram showing a detection method of position detection means in the printer of the present invention Schematic diagram showing after detection by the second position detecting means in the printer of the present invention. Side view showing an example of a conventional printer

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printer 2 Recording medium 11, 12, 13, 14 Recording unit
11a, 12a, 13a, 14a Ink ribbon
11b, 12b, 13b, 14b Thermal head
11m (for alignment) mark 11p, 12p, 13p, 14p Each color image 21, 22, 23, 24 Transport unit 21a, 22a, 23a, 24a Feed roller 21b, 22b, 23b, 24b Platen roller 31, 32, 33, 34 Position detection means 31a, 32a, 33a, 34a Light emitting element 31b, 32b, 33b, 34b Light receiving element 50 Control unit FD Transport direction A Mark print start position B Mark print end position C First color image print start position A ′ mark detection start position B ′ mark detection end position C ′ second color image printing start position D2 second recording unit prints the second color image from the position where the second position detection means detects the mark Transport amount to the position to start L Complementary color light

Claims (3)

A transport unit for transporting the recording medium;
A first recording unit for printing at least a mark on the conveyed recording medium;
A recording unit that prints at least one image disposed downstream of the first recording unit in the conveyance direction of the recording medium;
Position detection means for emitting complementary color light of the mark;
Comparison means for comparing the voltage of the input signal obtained from the position detection means with a reference voltage and outputting an output signal;
A printer comprising a control unit for controlling the first recording unit and another recording unit based on the output signal,
The printer according to claim 1, wherein the comparison means is formed so as to be capable of selecting a first reference voltage for detecting an end of the recording medium and a second reference voltage for detecting the mark.   2. The second reference voltage is set to a value between a voltage of an electric signal in a state where a position detection unit recognizes a recording medium and the first reference voltage. The printer described.   2. The control unit according to claim 1, wherein the control unit is configured not to perform control based on the output signal OS until a time required for image printing elapses after the position detection unit finishes detecting the mark. The printer according to 1 or 2.

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