JP4854093B2 - Wiper control device for inkjet printer - Google Patents

Description

  The present invention relates to an inkjet printer including a print head that ejects ink droplets onto a substrate to be conveyed, and more particularly to a wiper control device that performs wiping control on a nozzle arrangement surface of a print head.

A conventional ink jet printer of this type is shown in FIG. The illustrated ink jet printer includes a print head 2 disposed at a side position of a substrate C to be conveyed. A nozzle N is disposed at the tip of the print head 2. The nozzles N are adapted to print by ejecting ink droplets onto the printing material C that is placed on the conveyor B and conveyed at a constant speed V. In this case, the substrate C on the conveyor B is conveyed within an area (interference area M) surrounded by two one-dot chain lines.
On the other hand, the print head 2 includes a wiper 31 that performs cleaning by wiping the nozzle arrangement surface 2a on which the nozzles N are arranged. As indicated by the solid line in the drawing, the wiper 31 advances to the interference area M where there is a possibility of interference with the substrate C being conveyed, and wipes the nozzle arrangement surface 2a. Further, as indicated by a two-dot chain line in the figure, the wiper 31 is a non-interference area P that does not interfere with the substrate C being transported except when the print head is wiped (an outer area of the one-dot chain line Q near the wiper 31). Has been evacuated.
As described above, as an ink jet printer provided with a wiper for cleaning the nozzle arrangement surface of the print head, for example, one disclosed in Patent Document 1 below is known.

JP 2005-41141 A

By the way, the wiping operation by the wiper 31 is executed by a plurality of sequence operations, and the wiper 31 stays in the interference region M for several seconds. Further, it takes some time for the wiper 31 to move from the interference area M to the non-interference area P (for example, about 3 seconds). When a large number of printed materials are being conveyed closely, a wipe command may be issued to the wiper 31.
As a result, the wiper 31 cannot be retracted to the non-interference area P in time, and the substrate C may collide with the wiper 31. If the substrate C and the wiper 31 collide in this way, the ink attached to the wiper 31 may contaminate the substrate C, or eventually damage the substrate C or the wiper 31 and cause great damage.

  The present invention has been made in view of the above-described conventional problems, and a wiper that has to advance to a printing material conveyance path to wipe the nozzle arrangement surface of a print head interferes with the printing material. An object of the present invention is to provide a wiper control device for an inkjet printer that can prevent this.

  In order to achieve the above object, a wiper control device for an ink jet printer according to the present invention includes a wiper that is in sliding contact with a nozzle arrangement surface of a print head that sprays ink droplets onto a substrate to be conveyed at a predetermined speed. In a wiper control device for an ink jet printer that wipes a nozzle arrangement surface by moving a wiper from a non-interference area that does not interfere with a substrate to be conveyed during wiping to an interference region that interferes with the substrate, the substrate conveyance direction with respect to the print head At a position upstream of the printer and at a position where a predetermined transport time set in advance as a time for the substrate to be transported to the print head is longer than the time until the wiper in the interference area is retracted to the non-interference area. The upstream passage detection means for detecting the passage of the substrate and the upstream passage detection means for detecting the passage of the substrate. A time-counting means for measuring time from when an overload is detected, and when the time counted by the time-measurement means does not exceed the predetermined transport time, there is a printed material in the transport path between the upstream-side passage detection means and the print head. And a wiper control means for retracting the wiper to the non-interference area when the presence of the printed material in the transport path is detected by the first printed material presence detecting means. It is characterized by comprising.

  The wiper control device for an ink jet printer according to the present invention includes a wiper that slides in contact with a nozzle arrangement surface of a print head that ejects ink droplets onto a printed material that is conveyed at a predetermined speed, and is being conveyed while the print head is being wiped. In the wiper control device for an inkjet printer that wipes the nozzle arrangement surface by moving the wiper from the non-interference area that does not interfere with the printed material to the interference area that interferes with the printed material, at an upstream position in the printed material conveyance direction with respect to the print head, And an upstream-side passage detecting means for detecting the passage of the substrate to be printed, which is disposed at a position where it takes time to transport the substrate to the print head more than the time until the wiper in the interference region is retracted to the non-interference region. , Disposed downstream of the print head in the substrate transport direction and at a position where the wiper does not interfere. Based on the detection of the passage of the printed matter by the downstream passage detecting means and the detection of the passage of the printed matter by the downstream passage detecting means, the upstream passage detecting means and the downstream side When the presence of the printed material in the conveyance path is detected by the second printed material presence detection means for detecting the presence of the printed material on the conveyance path between the passage detection means and the second printed material presence detection means Wiper control means for retracting the wiper to the non-interference area.

  The second printed matter presence detecting means in the configuration of claim 2 increases the count number counted by the counting means when the counting means for counting and the passage of the printed matter is detected by the upstream passage detecting means. A count number increasing means; and a count number decreasing means for reducing the count number counted by the counting means when the passage of the printed material is detected by the downstream passage detecting means, and the count number increasing means and the count number decreasing means Based on the increased / decreased number of counts, it is configured to detect the presence of the printing material in the transport path between the upstream side passage detection unit and the downstream side passage detection unit.

  According to the ink jet printer of the present invention, the time measuring unit measures the time from when the upstream passage detection unit detects the passage of the printing material, and the time measured is conveyed from the upstream side detection unit to the print head. When the predetermined conveyance time of the printed material has not been exceeded, the first printed material presence detection unit detects that the printed material is present in the conveyance path between the upstream side detection unit and the print head. In this way, when the printing material is present in the transport path, the wiper control means retracts the wiper to the non-interference area and does not advance to the interference area, so that the wiper can be prevented from interfering with the printing material.

  In addition to the upstream passage detection means, in the case where the downstream passage detection means is provided at the downstream position in the substrate transport direction with respect to the print head, it is determined whether or not the substrate remains on the transport path. This can be detected by detecting the passage of the detection means. Therefore, for example, even in the case where the conveyance of the substrate is stopped in a state where the substrate remains in the conveyance path between the upstream passage detection unit and the downstream passage detection unit, and then the conveyance is resumed, Since the wiping operation is not performed with the wiper retracted until the printed material passes through the downstream passage detection means, contact interference between the wiper and the printed material can be reliably prevented.

  When the second printed material presence detection means includes the count number increasing means and the count number decreasing means, the count number increasing means counts when the upstream passage detecting means detects the passage of the printed material. The count number counted by the means is increased, and the count number decreasing means decreases the count number at the time of passage detection by the downstream-side passage detection sensor. Therefore, based on the count number of the count means obtained by the increase / decrease, for example, 0 When the value is other than the value, the presence detection of the printing material in the conveyance path is determined to be simple and inexpensive, such as determining that the printing material exists in the conveyance path between the upstream passage detection unit and the downstream passage detection unit. This can be realized by the configuration.

The best embodiment of the present invention will be described with reference to the drawings. The embodiment described below is merely an example embodying the present invention, and does not limit the technical scope of the present invention. FIG. 1 is a schematic perspective view showing an inkjet printer, a wiper control device, and a substrate to be printed according to an embodiment of the present invention, and FIG. 2 is a plan configuration diagram corresponding to FIG. However, the same constituent elements as those of the prior art shown in FIG. 6 are denoted by the same reference numerals and detailed description thereof may be omitted.
In each figure, the ink jet printer 1 according to this embodiment is disposed on the side of a conveyor B that conveys a substrate C (C (1) to C (4)) exemplified by a paper box or the like in the direction of arrow D. For example, an ink jet print head 2 is provided. The print head 2 has, for example, a dot matrix type structure in which a number of nozzles N, N, N,... Ink drops U (see FIG. 3C) are sprayed from the nozzles N, N, N,... The print head 2 is fixedly supported by a support frame installed on the floor or the like. The ink jet printer 1 includes a print drive unit 3 that operates a piezo element built in the print head 2 to cause the print head 2 to perform a printing operation. The print drive unit 3 outputs drive power to the piezoelectric elements of the print head 2 corresponding to each nozzle N in response to a command signal from the control unit 4 (detailed later).

  In the conveyor B, for example, an endless belt is wound around left and right rollers 26 and 26 (one roller 26 is not shown), and runs around by driving of the roller 26. The rotation speed of the roller 26 is controlled so that the speed V of the conveyor B detected by the transport speed sensor 11 is constant. An upstream-side passage detection that detects the passage of the front end CF of the substrate C at a position upstream of the print head 2 in the conveyance direction of the substrate C (the direction opposite to the arrow D) and on the side of the conveyor B. A sensor 5 (an example of upstream passage detection means) is provided. The upstream-side passage detection sensor 5 conveys the printing material C to the print head 2 through the upstream-side passage detection sensor 5 than the time until the wiper 31 in the interference region M is retracted to the non-interference region P. In this case, the predetermined transport time T is longer (a position indicated by a one-dot chain line H1 that is a distance L away from the print head 2).

In this case, the time until the wiper 31 in the interference area M completes retraction to the non-interference area P is measured a plurality of times to calculate the average time, and some margin is added to the calculated average retraction time. A value (for example, a value obtained by multiplying the average evacuation time by 1.2) was set as the predetermined conveyance time T. The data of the predetermined transport time T is input from the setting input unit 7 by the operator, set in the calculation unit 8 and stored in the storage unit 9, and is used for control of another embodiment described later. Further, the distance L is obtained by multiplying the predetermined transport time T by a constant speed V.
On the other hand, the downstream passage detection sensor 6 (an example of a downstream passage detection unit) is disposed at a downstream position in the transport direction of the substrate C with respect to the print head 2. Naturally, the position is a position where the wiper 31 does not interfere (a position indicated by a one-dot chain line H2). The downstream-side passage detection sensor 6 detects passage of the rear end CE of the substrate C. The downstream passage detection sensor 6 is desirably arranged as close to the print head 2 as possible within a range that does not interfere with the wiper 31.

  As the upstream-side passage detection sensor 5 and the downstream-side passage detection sensor 6, the substrate C being transported passes a predetermined position (a position indicated by a one-dot chain line H <b> 1 and a position indicated by a one-dot chain line H <b> 2 in FIG. 2). Although it will not specifically limit if it detects that it did, For example, the photoelectric tube type sensor is employ | adopted here. That is, the upstream passage detection sensor 5 and the downstream passage detection sensor 6 each have a built-in phototube, and a light source (not shown) is provided at the facing position of the upstream passage detection sensor 5 and the downstream passage detection sensor 6 across the conveyor B. Each is arranged so that the passage of the printing material C is detected when the printing material C being transported blocks light from the light source. The upstream passage detection sensor 5 and the downstream passage detection sensor 6 are provided with both a light source and a photoelectric tube, and when the light from the light source is reflected on the outer surface of the substrate C and detected by the photoelectric tube, the substrate C It may be configured to detect passage. In this example, the detection signal waveform of the upstream-side passage detection sensor 5 falls when the front end CF of the substrate C passes, and the detection signal waveform of the downstream-side passage detection sensor 6 rises when the rear end CE of the substrate C passes. (See FIG. 5).

The wiper control device 30 includes a head wiping mechanism 12 having a wiper 31 that is in sliding contact with the nozzle arrangement surface 2a of the print head 2, a wiper driving unit 13 that outputs a power source for driving the wiper 31 to the head wiping mechanism 12, and A control unit 4 that outputs a command signal related to the drive control of the wiper 31 to the wiper drive unit 13 is provided.
As shown in FIG. 3, the head wiping mechanism 12 has a wiper 31 that wipes in contact with the nozzle arrangement surface 2 a of the print head 2. A linear guide groove 35 is formed in the print head 2. One end of the guide groove 35 is open to the side surface of the print head 2. A slider 34 is slidably disposed in the guide groove 35, and the slider 34 reciprocates in the guide groove 35 by driving of a drive source m 1 disposed in the print head 2. Further, a vertical rotation shaft 33 is rotatably supported on the slider 34. The rotation shaft 33 is rotated by driving a drive source m2 provided in the print head 2. One end of an arm portion 32 formed in a plane U shape is fixed to the rotary shaft 33, and a wiper 31 is fixed to the other end of the arm portion 32. The wiper 31 is made of, for example, synthetic rubber and formed in a blade shape, and the sliding contact side is formed in a tapered flat cross section. And the side wall of the print head 2 near the edge of the conveyor B, which is located near the opening of the guide groove 35, is formed inwardly recessed. Thereby, the non-interference space 36 which avoids that the arm part 32 which turned has interfered with a side wall is formed.

  In the head wiping mechanism 12 configured as described above, when cleaning the nozzle arrangement surface 2a, first, the rotation shaft 33 is rotated by the drive of the drive source m2, and the arm portion 32 is brought into a posture parallel to the guide groove 35. The Then, the slider 34 moves to the inner part of the guide groove 35 by the drive of the drive source m1. At this time, as shown in FIG. 3A, the wiper 31 is on the nozzle arrangement surface 2 a at a position downstream of the nozzle N in the transport direction, and a part of the wiper 31 has advanced into the interference region M. Then, an elastic urging force in the clockwise direction in the drawing is applied to the rotating shaft 33. The elastic urging force is sufficient if the wiper 31 is slidably brought into close contact with the nozzle arrangement surface 2a and sufficient wiping can be performed.

Subsequently, from the state of FIG. 3A, the drive source m <b> 1 is driven to move the slider 34 to a position near the opening of the guide groove 35. Then, as shown in FIG. 3B, the wiper 31 slides on the nozzle arrangement surface 2a in the direction of the arrow S to wipe the remaining ink. The wiping operation shown in FIGS. 3A and 3B is not limited to once, and may be repeated a plurality of times.
Except during the wiping operation, as shown in FIG. 3C, the drive source m2 rotates the rotary shaft 33 in the direction of the arrow R from the state of FIG. Retreat to the non-interference area P. In such a retreat completion state, the substrate C passes through the interference region M, and ink droplets U from the nozzles N are sprayed onto the surface of the substrate C to be printed.

  As shown in FIG. 4, the control unit 4 includes a calculation unit 8 embodied by, for example, a microprocessor unit, a storage unit 9 embodied by a ROM or a RAM, and a data bus 10. An upstream passage detection sensor 5, a downstream passage detection sensor 6, a setting input means 7, and a conveyance speed sensor 11 are connected to the data input side of the data bus 10 so that signals can be input. The setting input means 7 is not particularly limited as long as the operator can set and input the conveyance speed V and the predetermined conveyance time T, and examples thereof include a keyboard, a mouse, and a tablet. On the data output side of the data bus 10, a print drive unit 3 for driving the print head 2, a wiper drive unit 13 for driving the head wiping mechanism 12, and a state in which wiping or wiping is prohibited is output to the outside. The external output device 14 is connected so that signal output is possible.

  As will be described in detail later, the calculation unit 8 includes functions of a time measuring unit 20, a first printed material presence detecting unit 21A, a second printed material presence detecting unit 21B, and a wiper control unit 25. Among them, the second printed material presence detection means 21B has functions of a count means 27, a count number increase means 22, a count number decrease means 23, and a presence determination means 24, which will be described later. Further, the first substrate presence detection means 21 </ b> A has the function of the presence determination means 24. Each of these functions is stored in advance in the storage means 9 as program data, and is used as necessary.

  Operations of the inkjet printer 1 and the wiper control device 30 configured as described above will be described. This embodiment corresponds to the inventions of claims 2 and 3. In this example, as shown in FIGS. 1 and 2, the printed materials C (1) to C (4) are placed on the conveyor B and conveyed at a constant speed V in the arrow D direction. The state before the printed material C (1) reaches the position indicated by the one-dot chain line H1 in FIGS. 1 and 2 will be described. The number of objects to be printed in the counter is reset to 0 by initial setting. At this time, the wiping operation prohibition command signal, the wiping command signal, the wiping sequence operation command signal, and the wiping display command signal are not input / output.

  Therefore, as shown in the time chart of FIG. 5, first, when the passage of the front end CF of the substrate C (1) is detected by the upstream side passage detection sensor 5 (signal falling portion, time point a), the second substrate The count number increase means 22 of the printed matter presence detection means 21B increases the count number of the count means 27 by one to become 1. This number of counts corresponds to the number of objects to be printed C present in the transport path A between the upstream side passage detection sensor 5 and the downstream side passage detection sensor 6. That is, the function of the count number increasing unit 22 increases the count number of the counting unit 27 by one when the upstream side detection sensor 5 detects the passage of the printing material C. Then, the presence determination unit 24 of the second substrate presence detection unit 21 </ b> B detects that there is one substrate C in the transport path A. At the same time, the wiper control means 25 of the calculation unit 8 outputs a wiping operation prohibition command signal to the print driving unit 3 to prohibit the wiping operation by the head wiping mechanism 12. That is, the wiper control means 25 keeps the wiper 31 retracted to the non-interference area P when the presence of the printing medium C existing in the transport path A is detected by the second printing medium presence detection section 21B. Do not advance to M. Subsequently, for the substrates C (2) and C (3), when the passage of the front end CF is detected by the upstream passage detection sensor 5 (time point b, time point c), the count number is increased to 3. Value. Thereafter, even if a wiping command signal is input from the outside to the wiper drive unit 13 (time point d), the wiper drive unit 13 does not execute the wiping operation because the wiping operation prohibition command signal is set by the calculation unit 8.

  Among them, when the passage of the rear end CE of the substrate C (1) is detected by the downstream-side passage detection sensor 6 (signal rising portion, time point e), the count number is reduced by 1 to 3 and becomes a value of 2. . That is, the function of the count number reducing unit 23 reduces the count number by the counting unit 27 when the passage of the printing material C is detected by the downstream side detection sensor 6. Next, the passage of the front end CF of the substrate C (4) is detected by the upstream passage detection sensor 5 (time point f), and the count number is increased to 3. As a result, the passage of the rear end CE of each of the substrates C (2), C (3), and C (4) is sequentially detected by the downstream passage detection sensor 6 (time point g, time point h, time point). i) The count is decremented by 1 to a value of 0. As a result, the presence determination unit 24 determines that there is no substrate C in the transport path A between the upstream-side passage detection sensor 5 and the downstream-side passage detection sensor 6.

  Then, at the time point i, the wiping operation inhibition command signal from the calculation unit 8 is canceled. At this time, since an external wiping command signal is still input, the calculation unit 8 outputs a wiping sequence operation command signal to the wiper driving unit 13, and the wiper driving unit 13 drives the driving source m 1 of the head wiping mechanism 12. The source m2 is driven to cause the wiper 31 to perform a sequence operation related to wiping the nozzle arrangement surface 2a of the print head 2. At the same time, a wiping display command signal for displaying that the print head 2 is being wiped is output from the calculation unit 8 to the external output device 14, and the external output device 14 transmits a signal to that effect to an external display device, for example. Then, this is displayed on the display device. Among them, when the input of the external wiping command signal is completed (time j), the output of the wiping sequence operation command signal from the calculation unit 8 is stopped, and the wiping operation of the print head 2 by the head wiping mechanism 12 is finished, and the wiper 31 retreats to the non-interference area P. At the same time, the output of the wiping display command signal from the calculation unit 8 is also stopped.

  As described above, the wiper control device 30 according to this embodiment includes the upstream-side passage detection sensor 5 and the downstream-side passage detection sensor 6, and therefore, between the upstream-side passage detection sensor 5 and the downstream-side passage detection sensor 6. The upstream passage detection sensor 5 can detect whether or not the substrate C has entered the transport path A, and the downstream passage detection sensor 6 can detect whether or not the substrate C has exited the transport path A. Can do. Therefore, for example, even when the conveyor B is stopped in a state where the substrate C remains in the conveyance path A and then the conveyor B is restarted, the substrate C in the conveyance path A is detected as a downstream passage detection sensor. The wiper 31 is retracted and the wiping operation is not performed until it passes 6. As a result, contact interference between the wiper 31 and the substrate C can be reliably prevented.

  Since the wiper control device 30 includes the count number increasing unit 22 and the count number decreasing unit 23, the count number increasing unit 22 counts up when the upstream side detection sensor 5 detects the passage of the printing material C, and the downstream side. When the passage detection by the side passage detection sensor 6 is performed, the count number reducing unit 23 counts down, and the count number by the counting unit 27 is increased or decreased. When the obtained count number is 1 or more, the printed material C is in the transport path A. The presence of the substrate C in the transport path A can be realized with a simple configuration (software or electronic circuit) as determined to be present.

  In the above-described embodiment, when the upstream side detection sensor 5 detects the passage of the printing material C, the count number increasing unit 22 adds a positive number to the count number of the counting unit 27, and the downstream side detection sensor 6. Although the positive number is reduced from the count number of the counting means 27 by the count number reducing means 23 when the passage of the printing material C is detected by the above, the wiper control device of the present invention is not limited to this. For example, the count number increasing unit 22 may add a negative number to the count number, and the count number decreasing unit 23 may subtract the negative number from the count number. Even in that case, the wiper 31 is controlled so as to be retracted to the non-interference area P except when the count number is zero.

As another embodiment corresponding to the invention of claim 1, the downstream passage detection sensor 6 is omitted, and the timing unit 20, the first printed material presence detection unit 21 </ b> A, and the calculation unit 8 all have, The structure using the function of the wiper control means 25 is illustrated. The first substrate presence detection means 21 </ b> A has the function of the presence determination means 24.
According to the wiper control device having such a configuration, the time measuring means 20 measures the time from when the upstream-side passage detection sensor 5 detects the passage of the front end CF of the substrate C, and the calculation unit 8 is timed by the time measuring means 20. The time is compared with a predetermined transport time T stored in advance in the storage means 9. As described above, the predetermined transport time T is a time required to transport the printing material C from the upstream-side passage detection sensor 5 to the print head 2, and the wiper 31 in the interference area M is retracted to the non-interference area P. It is set longer than the time until. Therefore, if the time measured by the time measuring means 20 does not exceed the predetermined transport time T, the presence determination means 24 of the first substrate presence detection means 21A is the transport path between the upstream side passage detection sensor 5 and the print head 2. It detects that the substrate C is present in AA. In this way, when the substrate C is present in the transport path AA, the wiper control means 25 retracts the wiper 31 to the non-interference area P and does not advance into the interference area M. Thereby, it is possible to prevent the wiper 31 from causing contact interference with the substrate C. Further, the downstream side passage detection sensor 6 is not used, so that the configuration can be simple and inexpensive.

1 is a schematic perspective view illustrating an inkjet printer, a wiper control device, and a printing material according to an embodiment of the present invention. It is a plane block diagram corresponding to FIG. It is operation | movement explanatory drawing which shows the operation | movement of the head wiping mechanism controlled by the said wiper control apparatus on a plane. It is a block block diagram which shows the control system of the said wiper control apparatus. It is a time chart which shows the control operation | movement by the said wiper control apparatus. It is a top view which shows the conveyance state of the general inkjet printer provided with the head wiping mechanism, and a to-be-printed object.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Inkjet printer 2 Print head 2a Nozzle arrangement surface 4 Control part 5 Upstream passage detection sensor (Upstream passage detection means)
6 Downstream passage detection sensor (downstream passage detection means)
8 Calculating unit 12 Head wiping mechanism 13 Wiper driving unit 20 Timing unit 21A First printed material presence detecting unit 21B Second printed material presence detecting unit 22 Count number increasing unit 23 Count number decreasing unit 25 Wiper control unit 27 Count unit 30 Wiper control Device 31 Wiper A, AA Conveyance path B Conveyor C, C (1), C (2), C (3), C (4) Substrate D Arrow H1 Dash-dot line H2 Dash-dot line L Distance N Nozzle M Interference area P Non-interference area T Predetermined transport time U Ink drop V Speed

Claims (3)

A wiper that slidably contacts the nozzle arrangement surface of the print head that ejects ink droplets onto the printed material conveyed at a predetermined speed, and interferes with the printed material from a non-interference area that does not interfere with the printed material being conveyed when wiping the print head. In the wiper control device of an inkjet printer that advances the wiper to the interference area and wipes the nozzle arrangement surface,
It is set in advance as the time for which the substrate is conveyed to the print head at a position upstream of the print head in the substrate conveyance direction and longer than the time until the wiper in the interference region is retracted to the non-interference region. An upstream-side passage detecting means that is disposed at a position that takes a predetermined conveyance time and detects the passage of the substrate;
A timing means for measuring the time from when the upstream passage detection means detects the passage of the substrate;
When the time measured by the time measuring means does not exceed the predetermined conveying time, the first printed material presence detecting means for detecting the presence of the printed material in the conveying path between the upstream passage detecting means and the print head;
An inkjet printer comprising: wiper control means for retracting the wiper to a non-interference area when the presence of the printed material in the transport path is detected by the first printed material presence detecting means. Wiper control device. A wiper that slidably contacts the nozzle arrangement surface of the print head that ejects ink droplets onto the printed material conveyed at a predetermined speed, and interferes with the printed material from a non-interference area that does not interfere with the printed material being conveyed when wiping the print head. In the wiper control device of an inkjet printer that advances the wiper to the interference area and wipes the nozzle arrangement surface,
It is located upstream of the print head in the substrate conveyance direction and at a position where it takes time to convey the substrate to the print head more than the time required for the wiper in the interference region to retreat to the non-interference region. Upstream side detection means for detecting the passage of the substrate;
A downstream passage detection means for detecting the passage of the substrate by being disposed at a position downstream of the print head in the substrate conveyance direction and at a position where the wiper does not interfere;
Based on the detection of the passage of the substrate by the upstream passage detection unit and the detection of the passage of the substrate by the downstream passage detection unit, the substrate is present in the conveyance path between the upstream passage detection unit and the downstream passage detection unit. Second substrate presence detecting means for detecting
An ink jet printer comprising: a wiper control means for retracting the wiper to a non-interference area when the presence of the printed material in the transport path is detected by the second printed material presence detecting means. Wiper control device. The second substrate presence detection unit includes: a counting unit that performs counting; a count number increasing unit that increases a count number counted by the counting unit when the passage of the substrate is detected by the upstream passage detection unit; and a downstream side And a count number reducing means for reducing the count number counted by the counting means when the passage detection means detects the passage of the printed material, based on the count number increased or decreased by the count number increasing means and the count number decreasing means. The wiper control device for an ink jet printer according to claim 2, wherein the wiper control device is configured to detect the presence of a printing material on a conveyance path between the upstream side passage detection unit and the downstream side passage detection unit.

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