JP2002051177A - Copying machine and equipment for diagnosing sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a copying machine in which failure of a reflection type sensor can be diagnosed. SOLUTION: The copy machine comprises a plurality of reflective sensors 1 disposed at prescribed positions, a medium 2 on which the plurality of reflective sensors 1 react, a carrier 3 fixed with the medium 2 and moving in a prescribed direction, and a control section (scanner control section) 4 for monitoring the reaction each of the plurality of reflection type sensors 1 during moving of the carrier 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copier and a sensor diagnostic apparatus, and more particularly, to a copier and a sensor diagnostic apparatus capable of diagnosing a failure of a detection sensor for detecting a plurality of paper sizes.

[0002]

2. Description of the Related Art In a copying machine, sheets (paper and other media) of various sizes smaller than the maximum size (size) that can be copied by the copying machine are usually copied. The maximum size is substantially equal to the size of the platen glass on which the paper is placed. Paper used in copiers is usually
So-called A-row paper and B according to JIS (Japanese Industrial Standards)
There are papers in a row, and each row has a size of 0th to 10th.

In a copying machine, the size of these papers is automatically detected (automatic paper size detection). In order to realize the automatic paper size detection function, for example, a reflection type detection sensor is used. The reflection-type detection sensor includes a pair of light-emitting elements and a light-receiving element, and detects the presence of the sheet by emitting light emitted from the light-emitting elements to the sheet and entering the pair of light-receiving elements.

[0004]

A reflection type detection sensor for automatic paper size detection is provided inside a housing of a copying machine due to its nature. Therefore, it is practically impossible to directly measure the output value. For this reason, in order to determine whether or not the reflection type detection sensor is normal, humans need to
Normally, the output value of the reflection-type detection sensor is monitored in a state where a sheet that reacts with the reflection-type detection sensor is actually placed on the original platen of the copying machine.

[0005] However, such a method is extremely troublesome. That is, a plurality of counts (all sizes readable by the copying machine, for example, No. 3 to No. 6) are prepared for each of the rows A and B, and the sheets are placed both vertically and horizontally. It is necessary to monitor the output value of the reflection type detection sensor for each state. That is, the loaded paper is compared with the paper size, which is the result of the automatic paper size detection displayed on the operation panel, to confirm whether or not the display is correct. Then, the paper is removed and there is no response. You have to make sure.

[0006] For this reason, a factory employee has to spend a lot of time for failure diagnosis of the reflection type detection sensor after shipment from a factory, and a maintenance person after shipment. Further, even if the reflection-type detection sensor fails during use after the copying machine is shipped, it has been impossible for the copying machine itself to detect this and output an alarm. For this reason, a considerable amount of time was required before the maintenance person noticed the failure of the reflection type detection sensor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a copying machine capable of diagnosing a failure of a reflection type detection sensor.

Another object of the present invention is to provide a sensor diagnostic device capable of diagnosing a failure of a reflection type detection sensor.

[0009]

According to the present invention, there is provided a copying machine comprising: a plurality of reflection type detection sensors provided at predetermined positions; a medium to which the plurality of reflection type detection sensors react; A carrier that moves in the direction, and a control unit that monitors the presence or absence of a reaction of each of the plurality of reflective detection sensors during the movement of the carrier.

According to the copying machine of the present invention, the presence or absence of a reaction of each of the plurality of reflection-type detection sensors is achieved by attaching a medium to a carrier having an inherently moving property and moving the medium using the movement of the carrier. To monitor. As a result, the copying machine itself can determine whether the reflection type detection sensor is normal or not, without the human being, and can output the result. Therefore, there is no need to prepare paper, place it, or check whether the result of automatic paper size detection is correct or not for diagnosis of the reflection type detection sensor. it can. Therefore, at the time of shipment from the factory or after shipment, failure diagnosis of the reflection-type detection sensor can be easily performed in a short time.

Further, the sensor diagnostic apparatus of the present invention comprises a plurality of reflection type detection sensors provided at predetermined positions, a medium to which the plurality of reflection type detection sensors react, and a medium attached thereto, and The control unit includes a moving carrier, and a control unit that monitors the presence or absence of a reaction of each of the plurality of reflective detection sensors during the movement of the carrier.

According to the sensor diagnostic apparatus of the present invention, for the same reason as described above, the sensor diagnostic apparatus itself determines whether or not the reflection type detection sensor is normal, without the human being. Can be output. Therefore, as described above, the trouble required for the diagnosis of the reflection-type detection sensor is not required at all, and the failure diagnosis of the reflection-type detection sensor can be easily performed in a short time at the time of shipment from a factory or after shipment. Can be done.

[0013]

1 to 4 show a first embodiment of a copying machine and a sensor diagnostic apparatus according to the present invention.

FIG. 1 is an explanatory view of a copying machine, and shows a schematic configuration of a copying machine having a reflection type detection sensor 1. In particular,
FIG. 1A shows an outline of the cross-sectional configuration, and FIG. 1B shows an outline of a planar configuration.

This copying machine comprises, for example, a digital copying machine, and includes a scanner unit (reading device) 100 and a printer unit (printing device) 200. The scanner unit 100 reads image information drawn on a sheet. The printer unit 200
The image information read by the scanner unit 100 is printed out. The scanner unit 100 and the printer unit 200 are provided in independent housings, are connected by a predetermined interface (not shown), and transmit and receive image information. Figure 1
As shown in (A), paper (paper, other medium) 300
Is placed on a transparent platen glass 102. The platen glass 102 is fitted over the housing 101 of the scanner unit 100.

As shown in FIG. 1, a scanner unit 100 of a digital copying machine includes a reflection type detection sensor 1, a medium 2, and a carrier 3.

A plurality of reflection sensors 1 (six in this case, S1 to S6) are provided at predetermined positions shown in FIG. A)
As shown in the figure, the scanner unit 100 is provided on the lower inner surface of the housing 101. The detection sensor 1 (S1 to S6)
Each of them independently outputs one beam and independently detects the reflected light. For this purpose, each detection sensor 1
Has a pair of light emitting elements (for example, light emitting diodes) and light receiving elements (phototransistors). Detection sensor 1
When the beam substantially output from the light emitting element in the vertical direction is reflected by the sheet 300, the reflected light is incident on the light receiving element, and the detection sensor 1 is turned on (reacts). This indicates that there is a sheet 300 at that position. If the sheet 300 is not located at the position corresponding to the beam, the beam is not reflected by the sheet 300, so that the reflected light does not enter the light receiving element, and the detection sensor 1 is turned off (does not react). In FIG. 1A, for convenience of illustration, the beam is depicted as being reflected by the platen glass 102, but is actually reflected by the paper 300.

The carrier 3 has a known configuration. That is,
The carrier 3 has a reading sensor 31 for reading image information drawn on a sheet 300. The carrier 3 is shown in FIG.
1A and 1B, it has a substantially rectangular parallelepiped shape, has a reading sensor 31 therein, and moves in the direction of the arrow (main scanning direction) in FIG. 1B. The carrier 3 includes, in addition to the reading sensor 31, a light source, a plurality of lenses, a reflecting mirror, and the like (all not shown).
It consists of a line sensor consisting of a CD (charge coupled device).
The carrier 3 is moved in the main scanning direction (and in the opposite direction) by a carrier motor 8 described later.

The medium 2 is to be responsive to the detection sensor 1. That is, the detection sensor 1 is made of a material that reacts similarly to the sheet 300. Furthermore, the reflectance of the light from the detection sensor 1 is equal to or higher than that of the sheet 300. As the medium 2, for example, a rectangular plate made of white plastic is used.

The medium 2 is mounted on a carrier 3 as shown in FIGS. 1 (A) and 1 (B). In particular, the carrier 3 is attached at the end in the main scanning direction and at the upper end thereof. As a result, the medium 2 protrudes from the carrier 3 like an eaves. In this example, as shown in FIG. 1A, the medium 2 has a uniform width in the main scanning direction, which is the moving direction of the carrier 3. That is, the end of the medium 2 opposite to the side attached to the carrier 3 is perpendicular to the main scanning direction. Thus, as shown in FIG. 1B, since the four detection sensors 1 are arranged vertically in the main scanning direction, they react with the medium 2 at the same time.

FIG. 2 is an explanatory diagram of the copying machine, and shows a schematic block configuration of the scanner unit 100 of the digital copying machine.
The scanner unit 100 includes six detection sensors 1 (S1 to S
6), scanner control unit 4, memory 5 of scanner unit 100, scanner unit 100 (and common to printer unit 200)
, A carrier motor driver 7, a carrier motor 8, and a carrier 3.

Note that the scanner control section 4 is
And a scanner control program existing on a main memory (not shown) of the scanner unit 100. The program is a CPU (Central Processing Unit, not shown).
This is realized by executing the above.

The detection data of the six detection sensors 1 is input to the scanner control unit 4. The scanner control section 4 temporarily stores the six pieces of detection data in the detection data section 51 of the memory 5 and performs the sheet size detection processing and the failure diagnosis processing of the detection sensor 1 using these pieces of data. The scanner control unit 4
Drives the carrier motor 8 by switching the excitation phase by controlling the carrier motor driver 7 by a known process, thereby moving the carrier 3. Further, although not shown, the scanner control unit 4 performs a known process on image data obtained by reading image information drawn on the sheet 300 from the reading sensor 31 of the carrier 3.

This digital copying machine has a normal operation mode and a failure diagnosis mode as its operation modes. The normal operation mode is a mode for reading (and printing out) image information drawn on the sheet 300, and the failure diagnosis mode is a mode for diagnosing a failure of the detection sensor 1. The scanner control unit 4 operates in the normal operation mode.
00 is controlled in a known manner, and a failure of the detection sensor 1 is diagnosed in the failure diagnosis mode. The two operation modes are specified (input instructions) by, for example, a maintenance person from a liquid crystal operation panel (not shown) of the digital copying machine. The normal operation mode is specified, for example, during normal operation after shipment, and the failure diagnosis mode is specified, for example, during inspection before shipment (and during maintenance).

When the failure diagnosis mode is designated, the scanner controller 4 moves the carrier 3 in a predetermined direction, and monitors whether or not each of the plurality of detection sensors 1 reacts while the carrier 3 is moving. That is, it monitors whether each of the detection sensors 1 correctly detects (reacts) the reflected light from the moving medium 2. Then, when at least one of the plurality of detection sensors 1 does not respond during the movement of the carrier 3, the scanner control unit 4 outputs failure information indicating a failure of the detection sensors 1. At this time, the scanner control unit 4 records (stores) the monitoring result in the detection data unit 51 of the memory 5, and outputs failure information based on the result. Therefore,
In the failure diagnosis mode, as shown in FIG.
00 must not be placed on the platen glass 102 (FIG. 1 shows the paper 300 for convenience of explanation), and the document cover (the oblique plate-like portion in FIG. 1A) must not be closed. .

On the other hand, when the normal operation mode is designated,
As shown in FIG. 1, the sheet 300 is a platen glass 10
2 is placed. The scanner control unit 4 monitors the presence or absence of a reaction of each of the plurality of detection sensors 1 and detects the size of the sheet 300 without moving the carrier 3. Then, the scanner control unit 4 detects the detection data unit 51 of the memory 5.
The size of the sheet 300 is determined by referring to a detection table (not shown) stored in the memory 5 based on a combination of the detection data of the six detection sensors 1 once stored in the memory 5, and outputting the result. I do.

FIG. 3 is a flowchart showing a process of detecting a failure of the detection sensor 1 in the digital copying machine. FIG. 4 is an explanatory diagram of a reaction of the detection sensor 1 in the failure diagnosis mode.

For example, when the power supply 6 is turned on by a maintenance person (step S11) and a failure diagnosis mode is input from the operation panel (step S12), the scanner control unit 4 controls the carrier motor driver 7 to control the carrier motor 8
, And the carrier 3 starts to move from the standby position toward the rear end in response to this (step S13).

The scanner control unit 4 monitors the presence or absence of a reaction of each of the plurality of detection sensors (document size sensors) 1 while the carrier 3 is moving, and records the monitoring result in the detection data unit 51 of the memory 5. (Step S14).

In step S14, as shown in FIG. 4A, immediately after the carrier 3 starts from its standby position, the medium 2 has not reached the upper part of any of the detection sensors 1 (S1 to S6). Therefore, since the beam output from the light emitting element of the detection sensor 1 is not reflected by the medium 2, the reflected light does not enter the light receiving element of the detection sensor 1, and any of the detection sensors 1 is turned off (does not react). . FIG.
In (and FIG. 7), the detection sensor 1 that does not react is indicated by a white circle.

Thereafter, the carrier 3 moves, and as shown in FIG.
As shown in (B), the medium 2 has four detection sensors 1 (S
1 to S4). Thereby, the beams output from the light emitting elements of the four detection sensors 1 are reflected by the medium 2, and the respective reflected lights enter the light receiving elements of the detection sensor 1, and the detection sensors 1 are turned on. (react). Therefore, the ON state of the four detection sensors 1 is recorded in the detection data section 51 of the memory 5. In FIG. 4 (and FIG. 7), the detection sensor 1 that has reacted is indicated by a black circle.

Thereafter, when the carrier 3 moves and the leading end of the medium 2 reaches the position of the rear end of the casing 101 (the upper end in FIG. 4B), the six detection sensors 1 For all, failure diagnosis data can be collected. When the remaining two detection sensors 1 (S5, S6) react during the movement to the rear end of the carrier 3, the detection sensors 1
Is operating correctly, and this is recorded in the detection data section 51. Therefore, if normal, ON of the six detection sensors 1 is recorded. On the other hand, if the detection sensor 1 does not respond even when the medium 2 passes over the upper part, the detection sensor 1 has failed. That is, the number of recorded ON states of the detection sensor 1 is 5 or less.

When the movement of the carrier 3 to the rear end is completed, the scanner controller 4 moves the carrier 3 from the position to the standby position (step S15).
With reference to the monitoring result of the detection data unit 51, it is checked whether or not there is a detection sensor 1 that has not responded based on the detection result (the number of recorded ON of the detection sensor 1 is 5 or less). (Step S16). If the recorded number of ONs of the detection sensor 1 is 6 and there is no undetected detection sensor 1, the process ends normally (step S17). However, the number of ONs of the detection sensor 1 recorded is 5 or less. If there is a detection sensor 1 that has not responded, it ends abnormally and notifies an error (step S18). For example, a failure of the detection sensor 1 (a paper size detection error) is displayed on the operation panel.

FIGS. 5 to 7 show a copying machine and a sensor diagnostic apparatus according to a second embodiment of the present invention. FIGS. 5 to 7 correspond to FIGS. 2 to 4, respectively. FIG.
The configuration shown in FIG.

The digital copying machine of this example has the same configuration as the digital copying machine of the first embodiment, but differs from the first embodiment in that it has a reaction order table 52 and the shape of the medium 2. .

The reaction order table 52 is provided in the memory 5, as shown in FIG. 5, and describes the order of the reactions of the plurality of detection sensors 1. For example, when the shape of the medium 2 is the shape shown in FIG. 7, the order is S1 to S6 shown in FIG. 7 (the reason will be described later). Therefore, the order S1, S2,... S5, S6 is described in the reaction order table 52. This order depends on the shape of the medium 2 and can be known in advance.

The medium 2 includes a carrier 3 as shown in FIG.
Is attached to the carrier 3 so as to have an uneven width with respect to the moving direction. That is, the end of the medium 2 on the side opposite to the side attached to the carrier 3 is not perpendicular to the main scanning direction (obliquely intersects). Thereby, as shown in FIG. 7B, the four detection sensors 1 (S1 to S1
Since 4) are arranged perpendicular to the main scanning direction, they will react to the medium 2 at different times. As shown by a solid line in FIG. 7, the medium 2 has a triangular shape (excluding a portion attached to the carrier 3).
The shape shown by the dotted line in FIG. Thereby, the reaction (reflected light) of the detection sensor S4 can be sufficiently ensured.

When the failure diagnosis mode is designated, the scanner controller 4 moves the carrier 3 in a predetermined direction, as described above, and determines whether or not each of the plurality of detection sensors 1 reacts while the carrier 3 is moving. And the presence or absence of the reaction and the order of the reaction are recorded (stored) in the detection data section 51 of the memory 5 as a result of the monitoring. Then, the scanner control unit 4 compares the result of the monitoring of the detection data unit 51 with the reaction order table 52, and when the order does not match, a failure of the detection sensor 1 and a failure indicating the failed detection sensor 1 Output information.

FIG. 6 is a flowchart showing a process of detecting a failure of the detection sensor 1 in the digital copying machine. FIG. 7 is an explanatory diagram of a reaction of the detection sensor 1 in the failure diagnosis mode.

After executing steps S21 to S23 in the same manner as steps S11 to S13 in FIG. 3, the scanner control unit 4 monitors the presence or absence of a reaction of each of the plurality of detection sensors 1 while the carrier 3 is moving. As a result of monitoring,
The presence or absence of the reaction and its order are recorded in the detection data section 51 of the memory 5 (step S24).

In step S24, as shown in FIG. 7A, immediately after the carrier 3 starts from its standby position, the detection sensor 1 is turned off (does not react) as in FIG. 4A. ).

Thereafter, the carrier 3 moves, and
As shown in (B), the medium 2 reaches the upper part of the four detection sensors 1. At this time, since the ends of the medium 2 are obliquely crossing in the main scanning direction, the four detection sensors 1 (S1 to S4) arranged in parallel react in this order. That is, first, as shown in FIG.
Is mostly covered with the medium 2. Accordingly, the beam output from the detection sensor S1 is reflected by the medium 2, and sufficient reflected light is incident on the light receiving element, and the detection sensor S1
Is turned on (reacts). Thus, the ON state of the detection sensor S1 is recorded in the detection data section 51 of the memory 5.
On the other hand, at this time, since the area of the detection sensor S2 covered by the medium 2 is less than half, the beam output from the detection sensor S2 is reflected by the medium 2, but sufficient reflected light is incident on the light receiving element. Without this, the detection sensor S2 is turned off (does not react).

Thereafter, when the carrier 3 moves a little, most of the detection sensor S2 is covered with the medium 2, and the detection sensor S2
1 is turned on (reacts), and the detection data section 51 records that the detection sensor S2 is on. That is, the detection data section 51
Are S1 and S2. On the other hand, at this time, since the area covered by the medium 2 with the detection sensor S3 is less than half, the detection sensor S3 is still turned off (does not react). Thereafter, similarly, with the slight movement of the carrier 3, the detection sensors S3 and S4 are sequentially turned on (react), and the recording of the detection data unit 51 is performed in S1, S2, S3,
It becomes S4.

Thereafter, when the carrier 3 moves and the leading end of the medium 2 reaches the position of the rear end of the casing 101 (the upper end in FIG. 7B), the six detection sensors 1 For all, failure diagnosis data can be collected. When the remaining two detection sensors 1 (S5, S6) react in this order during the movement to the rear end of the carrier 3, the detection sensors 1 are operating correctly, and the detection data unit 51 Recording is also performed in the order of S1 to S6. On the other hand, if the detection sensor 1 does not react even if the medium 2 passes over the upper part, or if the order of the reactions is different, the detection sensor 1 has failed.

After the scanner control unit 4 executes step S25 in the same manner as step S15, the result of the monitoring of the detection data unit 51 and the reaction order table (correct answer table) 5
2 and the order of reaction is the reaction order table 52
It is checked whether or not it matches (step S26). If the order is the same, the process ends normally (step S2).
7) If the two do not match, the process ends abnormally and notifies an error (step S18). For example, a failure (paper size detection error) of the detection sensor 1 is displayed on the operation panel, and failure information indicating the failed detection sensor 1 is output.

For example, if the record of the detection data section 51 is S1,
If the order is S3, S4, S5, and S6, since S2 did not respond, the detection sensor S2 is displayed as the failed detection sensor 1. Also, the records are S1, S3, S2,
In the order of S4, S5, and S6, S2 and S3 have reacted but the order is reversed, so that the detection sensors S2 and S3 are displayed as the failed detection sensor 1. This is to detect a case where the wirings of the detection sensors S2 and S3 are connected in reverse (the wiring mistake at the time of assembly).

Although the present invention has been described with reference to the embodiments, the present invention can be variously modified within the scope of the gist.

For example, the present invention can be applied not only to a copying machine but also to an electronic device which needs to automatically detect the size of a sheet. That is, the apparatus according to the present invention includes a plurality of reflection-type detection sensors 1 provided at predetermined positions, a medium 2 to which the plurality of reflection-type detection sensors 1 react, and a medium 2 to which the medium 2 is attached and moves in a predetermined direction. It can be configured as a sensor diagnostic device including the carrier 3 and a scanner control unit 4 that monitors the presence or absence of a reaction of each of the plurality of reflective detection sensors 1 while the carrier 3 is moving. And
This sensor diagnostic device can be mounted on various electronic devices such as a scanner and a facsimile.

[0049]

As described above, according to the present invention,
In the copying machine, the medium is moved by using the movement of the carrier, and the presence or absence of a reaction of the reflection type detection sensor is monitored to determine whether or not the reflection type detection sensor is normal. It is possible to eliminate the need to prepare and place paper for the diagnosis of the reflective detection sensor and check the result of automatic paper size detection at all.
As a result, the failure diagnosis of the reflection type detection sensor can be easily performed in a short time.

Further, according to the present invention, in the sensor diagnostic device, for the same reason as described above, whether or not the reflection type detection sensor is normal can be determined by the sensor diagnostic device itself. As described above, the trouble required for the diagnosis of the reflection type detection sensor can be completely eliminated, and as a result, the failure diagnosis of the reflection type detection sensor can be easily performed in a short time.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of a copying machine.

FIG. 2 is an explanatory diagram of a copying machine.

FIG. 3 shows a failure detection processing flow.

FIG. 4 is an explanatory diagram of a reaction of a detection sensor.

FIG. 5 is an explanatory diagram of a copying machine.

FIG. 6 shows a failure detection processing flow.

FIG. 7 is an explanatory diagram of a reaction of the detection sensor.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Detection sensor 2 Medium 3 Carrier 4 Scanner control part

Continued on front page F term (reference) 2G086 EE03 EE04 2H027 DB09 DE02 HA02 HA06 HA13 2H076 AA06 BB04 EA21 EA24 5C062 AA05 AC55 AC67 5C072 AA05 EA05 MB01 MB04 MB08 RA04 XA01

Claims (7)

[Claims] A plurality of reflective detection sensors provided at predetermined positions; a medium to which the plurality of reflective detection sensors react; a carrier to which the medium is attached and moves in a predetermined direction; A copying machine comprising: a control unit that monitors presence or absence of a reaction of each of the plurality of reflection-type detection sensors during movement of the carrier. 2. The control unit outputs failure information indicating a failure of the reflection-type detection sensor when at least one of the plurality of reflection-type detection sensors does not respond during movement of the carrier. The copier according to claim 1, wherein: 3. The control section monitors the presence or absence of a reaction of each of the plurality of reflection-type detection sensors during the movement of the carrier, records a monitoring result, and outputs the failure information based on the monitoring result. The copier according to claim 2, wherein 4. The medium is mounted on the carrier such that the medium has a uniform width in the moving direction of the carrier, and the carrier has a reading sensor for reading image information drawn on the paper. 4. The copying machine according to claim 3, wherein: 5. The copying machine further includes a reaction order table describing an order of reaction of the plurality of reflection-type detection sensors, wherein the medium has an uneven width in a moving direction of the carrier. Attached to the carrier, the carrier is equipped with a reading sensor that reads image information drawn on the paper, the control unit records the presence or absence of the reaction and the order of the reaction as a result of the monitoring Comparing the result of the monitoring with the reaction order table, and when the order in the two does not match, outputting failure information indicating a failure of the reflective detection sensor and a failed reflective detection sensor. The copier according to claim 3. 6. The copying machine has a normal operation mode for reading image information drawn on the paper and a failure diagnosis mode for diagnosing a failure of the reflection type detection sensor, wherein the failure diagnosis mode is designated. When the control unit is,
Move the carrier in a predetermined direction, monitor the presence or absence of each reaction of the plurality of reflective detection sensors during the movement of the carrier, when the normal operation mode is designated, the control unit,
The paper size according to any one of claims 1 to 5, wherein the presence or absence of a reaction of each of the plurality of reflection-type detection sensors is monitored to detect a sheet size without moving the carrier. Copy machine. 7. A plurality of reflection-type detection sensors provided at predetermined positions, a medium to which the plurality of reflection-type detection sensors react, a carrier to which the medium is attached, and which moves in a predetermined direction; A sensor for monitoring whether or not each of the plurality of reflection-type detection sensors has reacted during movement of the carrier.