JP2021033148A - Image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the presence / absence, position and the like of a medium on a medium transport path. SOLUTION: An optical medium detection sensor provided with a medium transport path, an image forming unit, a light emitting unit and a light receiving unit, and a light emitting amount of the light emitting unit are changed to define the light receiving amount of the light receiving unit. It has a sensor control unit 61 that sets the amount of light emitted when it becomes larger than the value as a control parameter by calibration. The sensor control unit 61 reads the light receiving amount of the light receiving unit when the light emitting unit is made to emit light after the medium reaches the medium detection sensor, and when the difference between the light receiving amount and the reference value is less than the threshold value. , Suppose that a sensor misalignment error occurs. By placing the medium detection sensor in an appropriate position, the control parameters of the medium detection sensor can be set. [Selection diagram] Fig. 1

Description

The present invention relates to an image forming apparatus.

Conventionally, an image forming unit is provided in an image forming apparatus such as a printer, a copying machine, a facsimile, or a multifunction device, for example, an electrophotographic printer, and the image forming unit includes a photoconductor drum, a charging roller, and a developing device. Etc. are arranged. In this type of printer, the surface of the photoconductor drum uniformly charged by the charging roller is exposed by the LED head to form an electrostatic latent image, and the electrostatic latent image is supplied from the toner cartridge to toner. Toner image is formed by being developed by. Then, the toner image is transferred to paper as a medium by a transfer roller and fixed in a fixing device to form an image and print.

By the way, in a printer in which roll paper as a roll-shaped medium is accommodated in a roll paper accommodating portion, and paper as a long medium is fed from the roll paper accommodating portion to a paper conveying path as a medium conveying path. , The presence / absence, position, etc. of paper on the paper transport path are detected by an optical sensor (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2017-24284

However, in the conventional printer, the position of the optical sensor on the paper transport path may shift, and if the optical sensor is calibrated in that state, the setting of the optical sensor becomes improper, and the presence or absence of paper is determined. It becomes impossible to detect the position and the like with high accuracy.

An object of the present invention is to solve the problems of the conventional printer and to provide an image forming apparatus capable of accurately detecting the presence / absence, position, etc. of a medium on a medium transport path.

Therefore, the image forming apparatus of the present invention includes a medium conveying path for conveying the medium set in the paper feeding section, an image forming section for forming an image on the medium, a light emitting section, and a light receiving section. An optical medium detection sensor that detects the medium conveyed in the medium transport path, and a control parameter by calibration that changes the amount of light emitted by the light emitting unit and determines the amount of light emitted when the amount of light received by the light receiving unit exceeds the specified value. It has a sensor control unit.

Then, the sensor control unit reads the light-receiving amount of the light-receiving unit when the light-emitting unit is made to emit light with a predetermined light-emitting amount after the medium reaches the medium detection sensor in the medium transport path, and uses the light-receiving amount as the light-receiving amount. It is assumed that a sensor misalignment error occurs when the difference from the reference value is less than the threshold value.

According to the present invention, the image forming apparatus includes a medium conveying path for conveying the medium set in the paper feeding section, an image forming section for forming an image on the medium, a light emitting section, and a light receiving section. An optical medium detection sensor that detects the medium conveyed in the medium transport path, and a control parameter by calibration that changes the amount of light emitted by the light emitting unit and determines the amount of light emitted when the amount of light received by the light receiving unit exceeds the specified value. It has a sensor control unit.

Then, the sensor control unit reads the light-receiving amount of the light-receiving unit when the light-emitting unit is made to emit light with a predetermined light-emitting amount after the medium reaches the medium detection sensor in the medium transport path, and uses the light-receiving amount as the light-receiving amount. It is assumed that a sensor misalignment error occurs when the difference from the reference value is less than the threshold value.

In this case, the sensor control unit reads the amount of light received by the light receiving unit when the light emitting unit is made to emit light with a predetermined amount of light emitted, and when the difference between the amount of light received and the reference value is less than the threshold value, the sensor position shifts. It is said that an error has occurred.

Therefore, the operator who has been notified that an error has occurred can set the control parameters of the medium detection sensor by placing the medium detection sensor in an appropriate position, so that the setting of the medium detection sensor is inappropriate. It is possible to prevent this from occurring, and it is possible to accurately detect the presence / absence, position, etc. of the medium.

Moreover, it is not necessary to reset the control parameter settings of the medium detection sensor.

It is a control block diagram of the printer in embodiment of this invention. It is a perspective view of the printer in embodiment of this invention. It is a perspective view which shows the main part of the printer in embodiment of this invention. It is the schematic of the printer in embodiment of this invention. It is a conceptual diagram of the printer in embodiment of this invention. It is a conceptual diagram of the optical sensor in embodiment of this invention. It is the first figure for demonstrating the arrangement state of the optical sensor in embodiment of this invention. It is a 1st flowchart which shows the operation of the calibration control part in embodiment of this invention. 2 is a second flowchart showing the operation of the calibration control unit according to the embodiment of the present invention. It is the first figure for demonstrating the state of the light emitting part and the light receiving part of the optical sensor in embodiment of this invention. It is a figure for demonstrating operation of the medium transport part in embodiment of this invention. It is a 2nd figure for demonstrating the arrangement state of the optical sensor in embodiment of this invention. It is a 2nd figure for demonstrating the state of the light emitting part and the light receiving part of the optical sensor in embodiment of this invention. It is a 3rd figure for demonstrating the arrangement state of the optical sensor in embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In this case, a printer as an image forming apparatus will be described.

FIG. 2 is a perspective view of the printer according to the embodiment of the present invention, FIG. 3 is a perspective view showing a main part of the printer according to the embodiment of the present invention, and FIG. 4 is a schematic view and a diagram of the printer according to the embodiment of the present invention. 5 is a conceptual diagram of a printer according to an embodiment of the present invention. In FIGS. 2 to 4, the negative X-axis direction is the front in the printer 10, the positive X-axis is the rear in the printer 10, the positive Y-axis is the upward in the printer 10, and the negative Y-axis is in the printer 10. The downward direction, the Z-axis positive direction, indicates the left direction in the printer 10, and the Z-axis negative direction indicates the right direction in the printer 10.

In the figure, reference numeral 10 denotes a printer, and the printer 10 is swingable with respect to the main body of the printer 10, that is, the device main body 11, the device main body 11 about the axis Cn1, and with respect to the device main body 11. The lid unit 12 is arranged so as to be openable and closable upward, and the toner cartridge unit Ct as a developer accommodating device arranged on the side of the lid unit 12 on the apparatus main body 11 is provided.

Further, Cs1 is a housing of the device main body 11, Cs2 is a housing of the lid unit 12, and the housing Cs1 includes a front panel Wf1, a side panel Ws1 and a rear panel Wr1, and the housing Cs2 is a front wall. It includes Wf2, side wall Ws2, back wall Wr2, and top wall Wt2. The top wall Wt2 includes a main body cover Wta and a roll cover Wtb that is swingably arranged around the axis Cn2 with respect to the main body cover Wta, and media is discharged at a predetermined position on the front panel Wf1. A paper outlet 13 as an outlet is formed.

The lid unit 12 is arranged directly under the roll cover Wtb, and serves as a medium accommodating portion for accommodating the roll paper 16 as a roll-shaped medium and as a paper feeding unit, and a roll paper accommodating portion 17 and a main body cover. A paper transport unit 18 as a first medium transport unit for transporting paper P as a long medium unwound from a roll paper accommodating unit 17 arranged directly under Wta, and the paper transport unit 18 In the present embodiment, a plurality of arms (not shown) are provided so as to project downward from the arm, and an LED head 22 as an exposure device is arranged at the lower end of each arm.

Further, a developer image forming unit Q1 that forms a toner image as a developer image of a plurality of colors, yellow, magenta, and cyan in the present embodiment below the paper transport unit 18 in the apparatus main body 11. However, the transfer unit u1 for sequentially transferring the toner image to the paper P and forming the color toner image below the developer image forming portion Q1 in the apparatus main body 11 forms the developer image in the apparatus main body 11. Behind the unit Q1 (on the rear panel Wr1 side), the paper transport unit 23 as a second medium transport unit for transporting the paper P sent from the paper transport unit 18 is in front of the transfer unit u1 in the apparatus main body 11. (Front panel Wf1 side) is provided with a paper transport unit 24 as a third medium transport unit for feeding the paper P sent from the paper transport unit 23 to the paper outlet 13.

Then, a transport roller pair 19 as a feeding member is rotatably arranged at a position adjacent to the front wall Wf2 in the roll paper accommodating portion 17. By rotating the transport roller pair 19, the paper P is fed from the roll paper accommodating portion 17 to the paper transport path Rt1 as the medium transport path.

The paper P is conveyed along the paper transfer path Rt1 between the paper transfer units 18 and 23, the developer image forming unit Q1 and the transfer unit u1, in the order of the paper transfer unit 24.

A paper end sensor Srx as a first detection unit for detecting the end portion (rear end) of the paper P is arranged at a position adjacent to the roll paper accommodating portion 17 in the paper transport path Rt1, and is provided in the paper transport path Rt1. A transport roller pair 20 as a first transport member is rotatably arranged on the downstream side of the paper end sensor Srx, and a transport roller pair 21 as a second transport member is rotatably arranged on the downstream side of the transport roller pair 20. A cutter unit 26 as a cutting portion is arranged on the downstream side of the transfer roller pair 21, and a transfer roller pair 27 as a third transfer member is rotatably arranged on the downstream side of the cutter unit 26. Arranged.

The paper P is conveyed by the rotation of the transfer rollers 20 and 21, then cut by the cutter unit 26, and further conveyed by the rotation of the transfer rollers 27. Further, on the downstream side of the transfer roller pair 27, a writing sensor Sr1 as a second detection unit for detecting a position at which image formation on the paper P starts, that is, a writing position is arranged.

Then, a transfer unit for transferring the toner image to the paper P is arranged between the developer image forming unit Q1 and the transfer unit u1 on the downstream side of the writing sensor Sr1 in the paper transport path Rt1, and the transfer is performed. A fixing device 45 as a fixing device is arranged on the downstream side of the fixing device, and an ejection sensor Sr2 as a third detecting section for detecting the front end of the paper P is arranged on the downstream side of the fixing device 45. A discharge roller pair 46 as a discharge member for feeding the paper P to the paper outlet 13 is rotatably arranged on the downstream side of the sensor Sr2. The developer image forming unit Q1, the transfer unit u1, and the fixing device 45 form an image forming unit for forming an image on the paper P.

The cutter unit 26 is a rotary cutter, and cuts the paper P by moving a rotary blade (not shown) in the width direction of the paper P while rotating the cutter unit 26.

Further, in the figure, 31Y, 31M and 13C are image forming units of each color of yellow, magenta and cyan, and each of the image forming units 31Y, 31M and 31C is photosensitive as a rotatably arranged image carrier. As a body drum 32, a charging roller 33 as a charging device rotatably arranged in contact with the photoconductor drum 32, and a developer carrier rotatably arranged in contact with the photoconductor drum 32. The developing roller 35 of the above, the toner supply roller 36 as a developer supply member rotatably arranged by being pressed against the developing roller 35, and the toner as a developing agent of each color arranged above the toner supply roller 36. A toner storage chamber 39 and the like as a developer storage room for storing the toner are provided. The toner storage chamber 39 is formed in the toner cartridge unit Ct.

In each of the image forming units 31Y, 31M, and 31C, the charging roller 33 is rotated as the photoconductor drum 32 is rotated, and the surface of the photoconductor drum 32 is uniformly charged, followed by exposure. The surface of the body drum 32 is exposed by the LED head 22, and an electrostatic latent image as a latent image is formed.

Then, as the photoconductor drum 32 is rotated, the developing roller 35 and the toner supply roller 36 are rotated, and the toner supplied from the toner cartridge 39 is supplied to the developing roller 35 by the toner supply roller 36, and the developing roller A toner layer composed of a thin layer of toner is formed on the 35.

Subsequently, the toner on the developing roller 35 is adhered to the electrostatic latent image, and a toner image of each color is formed on the photoconductor drum 32.

The transfer unit u1 serves as a traveling member stretched freely in the direction of arrow e by the driving roller R1 as the first roller, the driven roller R2 as the second roller, the driving roller R1 and the driven roller R2. A transfer roller 43 is provided as a transfer member that is arranged so as to face each photoconductor drum 32 via the transfer belt 41 and the transfer belt 41 and transfers a toner image of each color to the paper P.

The fixing device 45 includes a heating roller 48 as a first fixing member and a pressure roller 49 as a second fixing member, and heats and pressurizes a color toner image on the paper P to obtain a color image. To form.

The printer 10 is used to rotate the discharge roller pair 46, which is a first transport motor (not shown) as a drive unit for the first transport for rotating the transport roller pairs 19 to 21, 27. A second transfer motor (not shown) as a drive unit for second transfer, a cutter motor (not shown) as a drive unit for cutting for rotating a rotary blade in the cutter unit 26, and a developer image forming unit Q1. A drum motor (not shown) as a drive unit for image formation for rotating the photoconductor drum 32, the charging roller 33, the developing roller 35, and the toner supply roller 36, and the drive roller R1 and the transfer roller 43 in the transfer unit u1. A transfer motor (not shown) as a drive unit for transfer to rotate, a fixing motor (not shown) as a drive unit for fixing to rotate the heating roller 48 and the pressure roller 49 in the fuser 45 are arranged. To.

Further, in the printer 10, the paper P fed from the roll paper accommodating portion 17 to the paper conveying path Rt1 as the transport roller pair 19 arranged adjacent to the roll paper accommodating portion 17 is rotated. It is conveyed by the transfer roller pairs 20, 21, and 27, and is cut to a predetermined length by the cutter unit 26.

The cut and single paper P is conveyed by the transfer roller pair 27 and sent to the transfer unit, where the toner images of each color on the photoconductor drum 32 are displayed as the transfer belt 41 travels. It is sequentially transferred to the paper P, and a color toner image is formed on the paper P.

Subsequently, the paper P is sent to the fixing device 45, in which the color toner image is heated and pressurized to be fixed on the paper P, and a color image is formed on the paper P. The paper P printed in this way is discharged from the paper outlet 13 to the outside of the apparatus main body 11 by the discharge roller pair 46.

In the present embodiment, a paper without a mark such as a black mark is used as the paper P, but when an image is formed at a plurality of places on the paper P at a constant pitch, the paper P is used. Paper with marks such as black marks is used in a plurality of places in order to detect the presence / absence, position, and the like. In this type of paper, the marks are formed in a strip shape over the width direction of the paper, or are formed in a predetermined shape at a predetermined position in the width direction.

By the way, in order to form a color image on the paper P with high accuracy, a predetermined location on the paper transport path Rt1, in the present embodiment, is on the downstream side of the transport roller pair 21 and on the upstream side of the cutter unit 26. An optical sensor Sp as a medium detection sensor is arranged therein, and the presence / absence, position, etc. of the paper P on the paper transport path Rt1 are detected by the optical sensor Sp. Therefore, in the present embodiment, a reflection type sensor is used as the optical sensor Sp, but a transmission type sensor can also be used.

Next, the optical sensor Sp will be described.

FIG. 6 is a conceptual diagram of an optical sensor according to an embodiment of the present invention, and FIG. 7 is a first diagram for explaining an arrangement state of the optical sensor according to the embodiment of the present invention.

In the figure, Sp is an optical sensor, and the optical sensor Sp is arranged between the paper transport unit 23 (FIG. 4) and the back wall Wr2 so as to face the paper transport path Rt1, and includes LEDs and the like (not shown). It is composed of a light emitting portion Si, a light receiving portion Sr composed of a phototransistor or the like (not shown) arranged adjacent to the light emitting portion Si, and a transparent sensor cover 51 covering the light emitting portion Si and the light receiving portion Sr.

By the way, in the present embodiment, as described above, a paper without a mark such as a black mark is used as the paper P, but when the paper with the mark is used as the paper P, the paper P is used. The mark can be detected by the optical sensor Sp, and the presence / absence, position, etc. of the paper P can be detected.

However, as described above, each mark may be formed at a predetermined position in the width direction in a predetermined shape, so that the optical sensor Sp may be formed at any position in the width direction of the paper P. It is necessary to be able to detect the mark by.

Therefore, the optical sensor Sp is movably arranged in the width direction of the paper transport path Rt1, that is, in the direction perpendicular to the transport direction of the paper P in the paper transport path Rt1 (arrow E direction). Therefore, a rail 52 as a support member is arranged so as to extend in a direction perpendicular to the transport direction of the paper P, and the optical sensor Sp is slidably supported by the rail 52. The direction perpendicular to the paper transport direction in the paper transport path Rt1 is the main scanning direction of the optical sensor Sp.

The operator can manually move the optical sensor Sp and place it in the proper position on the rail 52.

Next, the control device of the printer 10 will be described.

FIG. 1 is a control block diagram of a printer according to an embodiment of the present invention.

In the figure, 10 is a printer, PC is a host computer as a host computer connected to the printer 10, and 55 is a host computer that receives print data, printing instructions, calibration instructions, etc. from the host computer PC. The interface unit 57 for transmitting the status (device status) of the printer 10 to the PC controls the entire printer 10 and is based on the print data received by the interface unit 55, print instructions, and the like. The print control unit 58 as a first control unit that executes printing is a calibration control unit 59 as a second control unit that executes calibration based on the calibration instruction received by the interface unit 55. Is the operation panel.

The operation panel 59 includes a display unit (not shown) including an LED screen or the like for displaying the status of the printer 10, and an operation unit (not shown) including switches, keys, or the like for an operator to input an instruction to the printer 10. ..

Further, 61 is a sensor control unit that controls the optical sensor Sp, 63 is a transport control unit that controls the transport of paper P in the paper transport path Rt1 (FIG. 5), and 65 is a developer image forming unit Q1 (FIG. 4) and The image control unit 67 that controls the transfer unit u1 is a fixing control unit that controls the fixing device 45.

The sensor control unit 61 monitors the optical sensor Sp, and when various errors occur, the sensor monitoring unit Pr1 as a notification processing unit that notifies the operator that an error has occurred, and a light emitting unit of the optical sensor Sp. It includes a light emitting amount adjusting unit Pr2 that emits Si and adjusts the light emitting amount of the light emitting unit Si, and a light receiving amount reading unit Pr3 that reads the light receiving amount of the light receiving unit Sr of the optical sensor Sp.

The transfer control unit 63 drives a transfer motor as a drive unit for transfer (not shown), engages and disengages a clutch (not shown) to rotate the transfer rollers 20, 21, 27 and the discharge roller pair 46, or transfers the transfer. Light receiving from the medium transport unit Pr11 and the optical sensor Sp that transport the paper P by driving the motor to rotate the drive roller R1 or driving the fixing motor to rotate the heating roller 48 and the pressurizing roller 49. A medium detection unit Pr12 for detecting the presence / absence, position, etc. of the paper P based on the amount of light received by the unit Sr, and a cutter control unit Pr13 for controlling the cutter unit 26 are provided.

The image control unit 65 transfers the image forming unit Pr21 for forming a toner image on each photoconductor drum 32 and the toner image formed on the photoconductor drum 32 to the transfer belt 41 in the developer image forming unit Q1. A transfer control unit Pr22 is provided.

The fixing control unit 67 includes a heater control unit Pr31 for controlling a heater (not shown) as a heating body arranged in the heating roller 48, and a temperature detecting unit Pr32 for detecting the temperature of the fixing device 45.

By the way, in the present embodiment, when detecting the presence / absence, position, etc. of the paper P, the light emitting amount of the light emitting unit Si of the optical sensor Sp and the light receiving unit Sr for determining whether or not the optical sensor Sp is on. It is desirable that the threshold value of the amount of received light is adjusted to a value suitable for the paper P used.

Therefore, when the paper P to be used is changed, the optical sensor Sp is calibrated using the newly used paper P, and the image is formed after the light emission amount and the threshold value are adjusted. It is said.

For example, in the printer described in Patent Document 1, when the paper is conveyed and reaches the position where the optical sensor is arranged, that is, the sensor position, the amount of light emitted by the light emitting portion is increased and the light received by the light receiving portion is received. The amount is a value specified for determining whether the optical sensor is on, that is, the amount of light emitted by the light emitting unit Si when the specified value is reached is a control parameter that is a value adjusted by calibration. Will be done.

However, if the optical sensor is not placed at an appropriate position through which the paper passes in the direction perpendicular to the paper transport direction, the amount of light received by the light receiving unit does not take a value corresponding to the amount of light emitted by the light emitting unit. Sometimes.

Further, when the optical sensor is a reflection type sensor and paper without a mark such as a black mark is used, the amount of light received by the light receiving portion increases by the amount that the light of the light emitting portion is reflected by the sensor cover. , The value corresponding to the amount of light emitted from the light emitting part may not be taken. Moreover, the amount of light reflected by the sensor cover changes depending on the individual difference of the sensor cover, the degree of dirt attached, and the like.

Therefore, in the printer described in Patent Document 1, when the paper is conveyed and reaches the sensor position, the optical sensor is not placed in an appropriate position and the paper is not on the optical sensor. However, when the light of the light emitting unit is reflected by the sensor cover and the light receiving amount of the light receiving unit reaches a specified value, the light emitting amount of the light emitting unit at that time becomes a control parameter.

As a result, the optical sensor is always on, so that the optical sensor cannot accurately detect the presence or absence of paper, the position, and the like.

In addition, it is necessary to reset the control parameter settings of the optical sensor in a predetermined procedure, which is troublesome.

In the present embodiment, when the optical sensor Sp is not placed at an appropriate position, even if the light receiving amount of the light receiving unit reaches a specified value, the light emitting amount at that time is not used as a control parameter.

Next, the operation of the calibration control unit 58 will be described.

FIG. 8 is a first flowchart showing the operation of the calibration control unit according to the embodiment of the present invention, FIG. 9 is a second flowchart showing the operation of the calibration control unit according to the embodiment of the present invention, and FIG. 10 is the present invention. FIG. 11 is a diagram for explaining the states of the light emitting unit and the light receiving unit of the optical sensor according to the embodiment of the present invention, and FIG. 11 is a diagram for explaining the operation of the medium transport unit according to the embodiment of the present invention, FIG. 2 is for explaining the arrangement state of the optical sensor according to the embodiment of the present invention, and FIG. 13 is a third diagram for explaining the state of the light emitting portion and the light receiving portion of the optical sensor according to the embodiment of the present invention. 2 and 14 are third views for explaining the arrangement state of the optical sensor according to the embodiment of the present invention.

When the operator executes the calibration of the optical sensor Sp on the host computer PC (FIG. 1), the host computer PC sends a calibration instruction to the printer 10 via the interface unit 55, and the calibration control unit 58 sends a calibration instruction. Calibration control is started.

Then, the sensor monitoring unit Pr1 of the sensor control unit 61 performs a short-circuit check of the sensor circuit of the optical sensor Sp, and determines whether or not the sensor circuit is short-circuited.

Therefore, the light emitting amount adjusting unit Pr2 stops the light emitting part Si of the optical sensor Sp, and in that state, the light receiving amount reading unit Pr3 reads the light receiving amount of the light receiving unit Sr and sends it to the sensor monitoring unit Pr1. The sensor monitoring unit Pr1 reads the received light amount and determines whether or not the sensor circuit is short-circuited depending on whether or not the received light amount is an abnormal value.

If the amount of received light is an abnormal value and the sensor circuit is short-circuited, the sensor circuit is out of order and calibration cannot be executed. Therefore, the sensor monitoring unit Pr1 determines that a short-circuit error has occurred, and determines that a short-circuit error has occurred. A short error signal is transmitted to the host computer PC via the interface unit 55, and the operator is notified by displaying on the display unit of the host computer PC that a short error has occurred.

On the other hand, when the light receiving amount is a normal value, the light emitting amount adjusting unit Pr2 causes the light emitting unit Si to emit light at a predetermined light emitting amount A, and the light receiving amount reading unit Pr3 is a reference of the light receiving amount. The light receiving amount B of the light receiving unit Sr as a value is read. In this case, since the light emitting portion Si is made to emit light in the state where the paper P does not exist on the optical sensor Sp, the light of the light emitting portion Si is not reflected by the paper P but is slightly reflected by the sensor cover 51. The light receiving amount B of the light receiving unit Sr is considerably smaller than the light emitting amount A.

Subsequently, the medium detection unit Pr12 of the transport control unit 63 waits for the paper P to be detected by the paper end sensor Srx, and when the paper P is detected, the roll paper 16 is transferred to the roll paper storage unit 17 by the operator. It is determined that the paper P is set in FIG. 4 and the tip of the paper P is inserted between the transfer rollers 20.

When the paper P is detected by the paper end sensor Srx, the roll paper 16 is set in the roll paper accommodating portion 17 by the operator, and the tip of the paper P is inserted between the transport rollers to 20, the medium transport of the transport control unit 63 The section Pr11 drives the transfer motor, engages the clutch, rotates the transfer roller pairs 20, 21, and 27, the paper P reaches the sensor position of the optical sensor Sp, and then the writing sensor Sr1 moves the paper P. Paper P is conveyed until the tip of the paper is detected.

When the writing sensor Sr1 detects the tip of the paper P, the medium transporting unit Pr11 stops the feeding of the paper P.

Then, the light emitting amount adjusting unit Pr2 causes the light emitting unit Si to emit light at the predetermined light emitting amount A, and the light receiving amount reading unit Pr3 reads the light receiving amount C of the light receiving unit Sr. At this time, as shown in FIG. 12, if the optical sensor Sp is placed on the rail 52 at an appropriate position Ar1 through which the paper P passes, the light of the light emitting portion Si is reflected by the paper P. The light receiving amount C of the light receiving unit Sr is sufficiently larger than the light emitting amount A.

Next, the light emitting amount adjusting unit Pr2 compares the light receiving amounts B and C, and determines whether or not the difference δ between the light receiving amount C and the light receiving amount B is equal to or greater than the threshold value δth.

When the difference δ between the light receiving amount B and the light receiving amount C is equal to or greater than the threshold value δth, it can be seen that the optical sensor Sp is placed at the appropriate position Ar1 on the rail 52 through which the paper P passes, so that the light emitting amount is adjusted. The unit Pr2 sets the amount of light emitted from the light emitting unit Si as an initial adjustment value for adjusting the amount of light emitted.

Subsequently, the light emitting amount adjusting unit Pr2 reads the light receiving amount D of the light receiving unit Sr read by the light receiving amount reading unit Pr3 when the light emitting amount is set as the adjustment initial value, and the light receiving amount D is set in advance. , It is determined whether or not it is larger than the specified value α for determining whether or not the optical sensor Sp is on.

When the light receiving amount D is equal to or less than the specified value α, the light emitting amount adjusting unit Pr2 increases the light emitting amount of the light emitting unit Si, and whether or not the light emitting amount of the light emitting unit Si reaches the maximum value in the specifications of the light emitting unit Si. to decide.

When the light emitting amount of the light emitting unit Si reaches the maximum value, it can be seen that the light receiving amount D does not become larger than the specified value α even if the light emitting amount is maximized due to a failure of the optical sensor Sp or the like. , It is determined that a calibration error has occurred, a calibration error signal is transmitted to the host computer PC via the interface unit 55, and an operation is performed by displaying on the display unit of the host computer PC that a calibration error has occurred. Notify the person.

On the other hand, when the light emitting amount of the light emitting unit Si does not reach the maximum value, the light emitting amount adjusting unit Pr2 determines whether or not the light receiving amount D increased by increasing the light emitting amount of the light emitting unit Si is larger than the specified value α. Judging, when the light receiving amount D is equal to or less than the specified value α, the light emitting amount of the light emitting unit Si is repeatedly increased.

When the light receiving amount D is larger than the preset specified value α, the light emitting amount adjusting unit Pr2 sets the light emitting amount of the light emitting unit Si at that time as a control parameter.

Subsequently, the medium transport unit Pr11 restarts the transport of the paper P, and when the transport amount of the paper P reaches a predetermined length, the cutter control unit Pr13 drives the cutter motor to push the rotary blade of the cutter unit 26. Rotate and cut the paper P.

Then, when the front end of the cut paper P is detected by the discharge sensor Sr2 (FIG. 5), the medium transporting unit Pr11 discharges the paper P from the paper outlet 13 to the outside of the apparatus main body 11 by the discharge roller pair 46, and the paper is discharged. Stop the transport of P. Further, the calibration control unit 58 ends the calibration control.

On the other hand, when the difference δ between the light receiving amount B and the light receiving amount C is less than the threshold value δth, the optical sensor Sp is placed at an appropriate position Ar1 on the rail 52 through which the paper P passes, as shown in FIG. Since it can be seen that the sensor misalignment error has not occurred, the sensor monitoring unit Pr1 determines that a sensor misalignment error has occurred, transmits a sensor misalignment error signal to the host computer PC via the interface unit 55, and displays the sensor misalignment error on the display unit of the host computer PC. , Notify the operator by displaying that a sensor misalignment error has occurred.

In the present embodiment, when the sensor monitoring unit Pr1 determines that a calibration error has occurred, the medium transfer unit Pr11 stops the transfer of the paper P and leaves the paper P in the paper transfer path Rt1. However, it is also possible to restart the transport of the paper P, cut the paper P, and discharge the paper P from the paper outlet 13 to the outside of the apparatus main body 11.

Further, in the present embodiment, when the sensor monitoring unit Pr1 determines that a sensor misalignment error has occurred, the medium transporting unit Pr11 stops the feeding of the paper P and leaves the paper P remaining in the paper transport path Rt1. However, the paper P can be retracted to the upstream side of the optical sensor Sp so that the operator can easily adjust the position of the optical sensor Sp.

Next, the flowchart will be described.
Step S1 The sensor monitoring unit Pr1 performs a short-circuit check on the sensor circuit of the optical sensor Sp.
Step S2 The sensor monitoring unit Pr1 determines whether or not the sensor circuit is short-circuited. If the sensor circuit is short-circuited, the process proceeds to step S3, and if the sensor circuit is not short-circuited, the process proceeds to step S4.
Step S3 The sensor monitoring unit Pr1 transmits a short error signal to the host computer PC and ends the process.
Step S4 The light emitting amount adjusting unit Pr2 causes the light emitting unit Si to emit light at a predetermined light emitting amount A, and the light receiving amount reading unit Pr3 reads the light receiving amount B of the light receiving unit Sr.
Step S5 The medium detection unit Pr12 waits for the paper P to be detected by the paper end sensor Srx. If the paper P is detected by the paper end sensor Srx, the process proceeds to step S6.
Step S6 The medium transporting unit Pr11 transports the paper P until the writing sensor Sr1 detects the tip.
Step S7 The light emitting amount adjusting unit Pr2 causes the light emitting unit Si to emit light at a predetermined light emitting amount A, and the light receiving amount reading unit Pr3 reads the light receiving amount C of the light receiving unit Sr.
Step S8 The light emitting amount adjusting unit Pr2 determines whether or not the difference δ between the light receiving amount C and the light receiving amount B is equal to or greater than the threshold value δth. If the difference δ between the light receiving amount C and the light receiving amount B is equal to or greater than the threshold value δth, the process proceeds to step S10, and if the difference δ between the light receiving amount C and the light receiving amount B is less than the threshold value δth, the process proceeds to step S9.
Step S9 The sensor monitoring unit Pr1 transmits a sensor misalignment error signal to the host computer PC, and ends the process.
Step S10 The light emitting amount adjusting unit Pr2 sets the light emitting amount of the light emitting unit Si as the adjustment initial value.
Step S11 The light emitting amount adjusting unit Pr2 reads the light receiving amount D of the light receiving unit Sr.
Step S12 The light emitting amount adjusting unit Pr2 determines whether or not the light receiving amount D is larger than the specified value α. If the light receiving amount D is larger than the specified value α, the process proceeds to step S13, and if the light receiving amount D is equal to or less than the specified value α, the process proceeds to step S15.
Step S13 The light emitting amount adjusting unit Pr2 sets the light emitting amount of the light emitting unit Si as a control parameter.
Step S14 The media transport unit Pr11 restarts the transport of the paper P, the cutter control unit Pr13 cuts the paper P, and the media transport unit Pr11 ejects the paper P to the outside of the apparatus main body 11 by the ejection roller pair 46, and the process is completed. To do.
Step S15 The light emitting amount adjusting unit Pr2 increases the light emitting amount of the light emitting unit Si.
Step S16 The light emitting amount adjusting unit Pr2 determines whether or not the light emitting amount of the light emitting unit Si has reached the maximum value. If the amount of light emitted reaches the maximum value, the process proceeds to step S17, and if the amount of light emitted does not reach the maximum value, the process returns to step S11.
Step S17 The sensor monitoring unit Pr1 transmits a calibration error signal to the host computer PC, and ends the process.

As described above, in the present embodiment, the sensor control unit 61 receives light when the light emitting unit Si emits light with a predetermined light emitting amount A after the paper P reaches the optical sensor Sp in the paper transport path Rt1. The light receiving amount C of the light receiving part Sr is read, and the light receiving amount C and the light receiving amount B of the light receiving part Sr when the light emitting part Si is made to emit light by the light emitting amount A before the paper P reaches the optical sensor Sp. When the difference δ is less than the threshold value δth, it is determined that the optical sensor Sp is not placed at the proper position Ar1 and a sensor misalignment error has occurred.

Therefore, the operator who has been notified that an error has occurred can set the control parameters of the optical sensor Sp by placing the optical sensor Sp at the appropriate position Ar1, so that the setting of the optical sensor Sp is not possible. It is possible to prevent it from becoming appropriate, and it is possible to accurately detect the presence / absence, position, etc. of the paper P.

Further, it is not necessary to reset the control parameter settings of the optical sensor Sp.

In the present embodiment, the case where the paper P to which the mark such as the black mark is not given is used has been described, but the present invention uses the paper P to which the mark such as the black mark is given. Can be applied in case.

Further, in the present embodiment, a reflective sensor is used as the optical sensor Sp. However, a transmissive sensor is used, and a transmissive sensor is used to attach a label to the mount. It is also possible to detect the presence / absence and position of (label paper).

In that case, for example, the transmissive sensor is provided with a light emitting portion facing the side on which the label is affixed on the mount, that is, the surface of the paper P, and facing the light emitting portion via the paper transport path Rt1. A light receiving part is arranged.

Further, in the present embodiment, when various errors occur, the sensor monitoring unit Pr1 transmits an error signal to the host computer PC via the interface unit 55, and an error occurs in the display unit of the host computer PC. Although the operator is notified by displaying the fact, it is also possible to display the fact that an error has occurred on the display unit of the operation panel 59 of the printer 10 and notify the operator.

The present invention is not limited to the above-described embodiment, and various modifications can be made based on the gist of the present invention, and these are not excluded from the scope of the present invention.

10 Printer 17 Roll paper accommodating unit 45 Fuser 61 Sensor control unit Ar1 Position P Paper Q1 Developer image forming unit Rt1 Paper transport path Si Light emitting unit Sp Optical sensor Sr Light receiving unit u1 Transfer unit

Claims (10)

(A) A medium transport path for transporting the medium set in the paper feed section, and
(B) An image forming unit that forms an image on a medium,
(C) An optical medium detection sensor provided with a light emitting unit and a light receiving unit to detect a medium conveyed through the medium transfer path, and an optical medium detection sensor.
(D) It has a sensor control unit that changes the light emission amount of the light emitting unit and sets the light emission amount when the light reception amount of the light receiving unit becomes larger than a specified value as a control parameter by calibration.
(E) The sensor control unit reads the amount of light received by the light receiving unit when the light emitting unit is made to emit light with a predetermined amount of light emitted after the medium reaches the medium detection sensor in the medium transport path, and the amount of light received is read. An image forming apparatus, characterized in that a sensor misalignment error occurs when the difference between the sensor position and the reference value is less than a threshold value. The image forming apparatus according to claim 1, wherein the specified value represents the amount of light received by the light receiving unit when the medium detection sensor is on. The image forming apparatus according to claim 1 or 2, wherein the sensor misalignment error occurs when the medium detection sensor is not placed in an appropriate position. Claims 1 to 3 use the light receiving amount of the light receiving unit as a reference value when the light emitting unit emits light at the predetermined light emitting amount before the medium reaches the medium detection sensor in the medium transport path. The image forming apparatus according to any one of the above. Claims 1 to 4 use the light emitting amount of the light emitting unit as a control parameter by calibration when the difference is equal to or more than a threshold value and the light receiving amount of the light receiving unit is larger than a specified value. The image forming apparatus according to any one of the above. The sensor control unit sets the light emitting amount of the light emitting unit when the difference is equal to or greater than the threshold value as the adjustment initial value, and the light receiving amount of the light receiving unit becomes larger than the specified value when the light emitting amount of the light emitting unit is set as the adjustment initial value. The image forming apparatus according to claim 5, wherein the amount of light emitted is increased up to. The sensor control unit determines that a calibration error has occurred when the light emitting amount of the light emitting unit reaches the maximum value before the light receiving amount of the light receiving unit becomes larger than the specified value, and indicates that the calibration error has occurred. The image forming apparatus according to claim 6, which notifies the operator. (A) The medium detection sensor is a reflection type sensor.
(B) The image forming apparatus according to any one of claims 1 to 7, wherein the light receiving unit receives light emitted by the light emitting unit and reflected by the medium. The image forming apparatus according to any one of claims 1 to 8, wherein the medium detection sensor is movably arranged in a direction perpendicular to the transport direction of the medium in the medium transport path. The image forming apparatus according to any one of claims 1 to 9, wherein the medium detection sensor includes a sensor cover that covers a light emitting portion and a light receiving portion.

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