JP2022048687A - Image formation device - Google Patents

Abstract

To provide an image formation device that can read the size of a piece of printing paper without wasting the paper, by using an existing reflective-type light sensor for adjusting the concentration of an image instead of using a dedicated reading sensor.SOLUTION: Light is applied on a patch toner image by controlling a reflective light sensor when the concentration of an image is adjusted, the concentration of the image is adjusted by an image concentration adjusting unit on the basis of the reflected light, a conveying unit and the reflective light sensor are controlled and light is applied to the reflective light sensor when a predetermined region of a recording medium passes at the time of image formation, and whether the size of the recording medium is appropriate is determined on the basis of the reflected light.SELECTED DRAWING: Figure 7

Description

The present invention relates to an image forming apparatus, and more particularly to an image forming apparatus having a printing paper size detecting function.

An image forming apparatus such as a multifunction device having a printing paper size detection function is known.
In such an image forming apparatus, conventionally, a dedicated reading sensor has been provided in the transport path of printing paper in order to detect whether or not the size of printing paper matches the set paper size.

For example, as an invention of an image forming apparatus provided with such a reading sensor, a photo sensor is used when the upper part of the lever 52 arranged near the center of the transport path and the lever 53 arranged near the end of the transport path are without paper. The length and width of the paper in the transport direction are detected depending on the timing of crossing the 51 or the presence or absence of the crossing operation. An invention of an image forming apparatus that changes a position according to a surface temperature of a fixing roller is disclosed (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 7-129027

Further, a dedicated reading sensor is provided on the printing paper transport path at a predetermined reference position (for example, a position of 80.25 mm) from the center of the main scanning direction, and the width of the paper size in the main scanning direction is determined by this reading sensor. Also known is an invention of an image forming apparatus for determining whether the width is longer or shorter than the reference width.

As a result, it is possible to know whether or not the size of the printing paper matches the length of the image to be printed in the sub-scanning direction. It is possible to prevent the generation of dirt.

However, there is a problem that it is costly because it is necessary to provide a dedicated reading sensor for detecting the size of the printing paper.

The present invention has been made in consideration of the above circumstances, and an object thereof is to use an existing reflective optical sensor for image density adjustment in combination without using a dedicated reading sensor. It provides an image forming apparatus capable of reading the size of printing paper without wasting printing paper.

(1) The present invention comprises a transport unit that transports a recording medium along a transport path, an image forming unit that forms an image on the recording medium based on image data, a reflection type optical sensor for adjusting image density, and the above. An image forming apparatus including an image density adjusting unit that adjusts the image density based on the detection result of the reflective optical sensor and a control unit, wherein the image forming unit comes into contact with the photoconductor and the photoconductor. A charged unit to be charged, an exposed unit that forms an electrostatic latent image on the photoconductor, a developing unit that supplies toner to the photoconductor to form a toner image corresponding to the electrostatic latent image, and the toner image. The reflective type includes a transfer unit that transfers the toner image to the recording medium, a fixing unit that heats and fixes the toner image to the recording medium by a fixing roller, and a double-sided printing control unit that reverses the front and back of the recording medium during double-sided printing. The optical sensor is provided so as to face the photoconductor with the transport path interposed therebetween and to irradiate light at a position separated from the center line of the transport path by a predetermined distance in the main scanning direction. When adjusting the image density, the control unit controls the charging unit, the exposure unit, and the developing unit to form a predetermined patch toner image on the photoconductor, and then controls the reflection type optical sensor. Then, the patch toner image is irradiated with light, the image density adjusting unit is made to adjust the image density based on the reflected light, and at the time of image formation, the transport unit and the reflection type optical sensor are controlled to record. The reflective optical sensor is irradiated with light at the timing when a predetermined region of the medium passes, and based on the reflected light, it is determined whether or not the size of the recording medium is appropriate, and then the size of the recording medium is determined. When appropriate, the double-sided printing control unit inverts the recording medium, and then the image forming unit forms an image. On the other hand, when the size of the recording medium is not appropriate, the image forming unit forms an image. Provided is an image forming apparatus characterized in that the image forming apparatus is not formed.

In the present invention, the "image forming apparatus" is a copying machine or a multifunction device having a copying function such as a printer using an electrophotographic method for image formation by a toner, or an MFP (Multifunctional Peripheral:) including a function other than copying. It is a device that forms and outputs an image, such as a multifunction peripheral device).

In the first embodiment, the "reflection type optical sensor" of the present invention is realized by the image quality adjustment sensor 78. Further, the "photoreceptor", "charged part", "exposed part", "development part", "transfer part" and "fixing part" of the present invention are the photoconductor drum 202, the charger 203, and the laser writing unit, respectively. It is realized by 201, a developer 204, a transfer device 205 and a fixing unit 208.

According to the present invention, the size of the printing paper can be read by using the existing reflective optical sensor for adjusting the image density without using a dedicated reading sensor, and the size of the printing paper is inappropriate. Even in this case, since the image is not formed when the reflective optical sensor is read, the image forming apparatus in which the printing paper is not wasted is realized.

Further, preferred embodiments of the present invention will be described.

(2) In the image forming apparatus according to the present invention, the control unit controls the transport unit and the reflection type optical sensor, and the reflection type optical sensor at a timing when a predetermined tip region of the recording medium passes through. May be irradiated with light, and based on the reflected light, it may be determined whether or not the width of the recording medium in the main scanning direction is longer than a predetermined reference width.

By doing so, the length of the printing paper in the main scanning direction can be determined based on the reflected light when the reflective light sensor is irradiated with light at the timing when the predetermined tip region of the printing paper passes. It is possible to realize an image forming apparatus that can read the size of the printing paper without wasting the printing paper.

(3) In the image forming apparatus according to the present invention, the control unit controls the transport unit and the reflection type optical sensor to pass the predetermined front end region and rear end region of the recording medium. A reflective light sensor may be irradiated with light, and based on the time difference between the reflected lights, it may be determined whether or not the width of the recording medium in the sub-scanning direction is longer than a predetermined reference width. ..

In this way, the length of the printing paper in the sub-scanning direction is based on the time difference of the reflected light when the reflective light sensor is irradiated with light at the timing when the predetermined front end region and rear end region of the printing paper pass. By determining, it is possible to realize an image forming apparatus that can read the size of the printing paper without wasting the printing paper.

(4) In the image forming apparatus according to the present invention, an operation unit that accepts the setting of whether or not the size of the recording medium should be determined by the reflective optical sensor and the type of the recording medium including the backing paper is further provided. The control unit has the image when the type of the recording medium set by the user is the backing paper when the setting for determining the size of the recording medium by the reflection type optical sensor is effective. The forming portion may interrupt the formation of the image.

By doing so, when the setting for determining the size of the recording medium by the reflective optical sensor is effective, the image formation is interrupted when the backing paper is used as the paper type, so that the printing paper is wasted. It is possible to realize an image forming apparatus that can read the size of printing paper without making it.

(5) In the image forming apparatus according to the present invention, the control unit controls the transport unit and the reflection type optical sensor to start determining whether or not the size of the recording medium is appropriate, and the fixing unit. The heating of the fixing roller may be started.

In this way, the determination of whether or not the size of the recording medium is appropriate is started, and the fixing portion is started to heat the fixing roller. Therefore, when the size of the recording medium is appropriate, the temperature of the fixing roller is waited for to rise. It is possible to realize an image forming apparatus that does not need to be used.

It is a perspective view which shows the appearance of the digital multifunction device provided with the image reader of this invention. It is sectional drawing which shows the internal structure of the digital multifunction device of FIG. It is a block diagram which shows the schematic structure of the digital multifunction device of FIG. It is explanatory drawing which shows the schematic structure of the visible image formation unit of the digital multifunction device of FIG. It is explanatory drawing which shows an example of the detection of the length in the main scanning direction of the recording medium of the digital multifunction device of FIG. It is explanatory drawing which shows an example of the detection of the length in the sub-scanning direction of the recording medium of the digital multifunction device of FIG. It is a flowchart which shows an example of the size detection processing of the recording medium of the digital multifunction device of FIG. It is a flowchart which shows an example of the size detection processing of the recording medium of the digital multifunction device of Embodiment 2 of this invention. It is a flowchart which shows an example of the size detection processing of the recording medium of the digital multifunction device of Embodiment 3 of this invention.

Hereinafter, the present invention will be described in more detail with reference to the drawings. It should be noted that the following description is exemplary in all respects and should not be construed as limiting the invention.

[Embodiment 1]
<Configuration of digital multifunction device 1>
Hereinafter, the outline of the digital multifunction device 1 as an example of the image forming apparatus according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2.
FIG. 1 is a perspective view showing the appearance of the digital multifunction device 1 according to the first embodiment of the present invention.
FIG. 2 is a cross-sectional view showing the internal configuration of the digital multifunction device 1 of FIG.

The digital multifunction device 1 has a copying function, a scanner function, and a facsimile function, and is a device that digitally processes and outputs image data read from a document.

The digital multifunction device 1 has a copy (copy) function, a print function, and a FAX function as print modes, and receives operation input from the touch panel 17 (FIG. 3) and a print job from an external device such as a personal computer. The printing function according to the above is selected by the control unit 10 (FIG. 3).

<Internal configuration of digital multifunction device 1>
In FIG. 2, the digital compound machine 1 is a monochrome compound machine, an image reading unit 100 that reads an image from a document and generates image data, and an image forming unit 200 that forms an image on a recording medium 31 based on the image data. It includes a paper feed unit 300 for accommodating a recording medium 31 supplied and conveyed to the image forming unit 200, and a paper ejection unit 400 for discharging the recording medium 31 image formed by the image forming unit 200.

The image reading unit 100 includes an image reading unit 15 including a light source unit 110, a mirror unit 120, and a CCD reading unit 130 (CCD: Charge Coupled Device), and is a document placed on a platen glass platen 101. Or, the image of the document conveyed from the automatic document transfer device 102 that separates and feeds the documents one by one is optically read.

The light source unit 110 is installed with the light source 111 that irradiates the document with irradiation light for reading and the reflection surface tilted at 45 ° with respect to the surface of the platen 101 in order to change the optical path of the reflected light from the document by 90 °. It is equipped with a mirror 112. Further, the light source unit 110 is configured to move in parallel to the surface of the platen 101 by a stepping motor (not shown in the figure), and scans the reading surface of the document placed on the platen 101. I am doing it.

The mirror unit 120 includes a pair of mirrors 121, 122 arranged so that the reflecting surfaces are orthogonal to each other in order to further change the optical path of the reflected light changed by 90 ° by the mirror 112 of the light source unit 110 by 180 °. ing. The CCD reading unit 130 includes an imaging lens 131 and a CCD sensor 132, and images reflected light from a document passing through the light source unit 110 and the mirror unit 120 on the CCD sensor 132 via the imaging lens 131. ..

The image formed on the CCD sensor 132 is taken out as an analog electric signal and converted into a digital signal by an AD converter (not shown in the figure). The converted digital signal is once held in an image memory (not shown) as digital image data after corrections such as the light distribution characteristics of the light source at the time of reading the original and the sensitivity unevenness of the CCD sensor 132, and image formation is performed. It is sent to the unit 200.

The image forming unit 200 includes an image forming unit 12 including a laser writing unit 201, a photoconductor drum 202, a charger 203, a developer 204, a transfer device 205, a cleaner 206, a static eliminator 207, and the like, and is an image reading unit. Image data generated by 100, image data obtained by developing a print job from an external information processing device (not shown), or facsimile data obtained by decoding an external facsimile device (not shown). A recording medium supplied and conveyed from the paper feed cassette 210 provided inside the self, the manual feed tray 211 provided on the side surface, or the paper feed unit 300 provided at the bottom of the image forming unit 200 based on the image data. Image formation is performed on 31.

The paper feed unit 300 includes paper cassettes 301 and 302 that accommodate a large amount of recording media 31 of various sizes. The recording media 31 housed in the paper cassettes 301 and 302 are separately supplied one by one by the calling rollers 301a and 302a according to the instruction from the image forming unit 200, and the image forming of the image forming unit 200 is formed through the paper transport paths 303 and 212. It is conveyed to the unit 12.

Hereinafter, the operation of the image forming unit 200 will be described. The image data described above is sent to the storage unit 13 (FIG. 3) and stored in a predetermined storage area in the storage unit 13. The stored image data is sequentially read out at the timing instructed by the control unit 10 (FIG. 3) and transferred to the laser writing unit 201, which is an optical writing device.

The laser writing unit 201 includes a semiconductor laser light source 111 that emits laser light according to the image data transferred from the storage unit 13, a polygon mirror that deflects the laser light at an equiangular velocity, and a photoconductor that the laser beam deflected at the equiangular velocity is used as a photoconductor. It is composed of an f−θ lens or the like that corrects to be deflected at an equal angular velocity on the drum 202.

In the first embodiment of the present invention, the laser writing unit 201 is used as the optical writing device, but it is a fixed scanning type using a light emitting element array such as an LED (Light Emitting Diode) and an EL (Electro Luminescence). An optical writing head unit may be used.

Around the photoconductor drum 202, there is a charger 203 that charges the photoconductor drum 202 to a predetermined potential, and a developer 204 that supplies toner to an electrostatic latent image formed on the photoconductor drum 202 to visualize it. The transfer device 205 for transferring the toner image formed on the surface of the photoconductor drum 202 onto the recording medium 31 conveyed from the paper feed cassette 210, the manual feed tray 211, or the paper feed unit 300, and the toner image are transferred. A static eliminator 207 that removes electric charges from the recording medium 31 and peels off the recording medium 31 from the photoconductor drum 202, and a cleaner 206 that recovers the residual toner after transferring the toner image are arranged.

The recording medium 31 on which the image is transferred is conveyed to the fixing unit 208, and the image is fixed on the recording medium 31 by the fixing unit 208. The recording medium 31 on which the image is fixed is sent to the paper ejection unit 400 by the paper ejection roller 209.

Further, the image forming unit 200 can perform double-sided printing by forming an image again on the back surface of the recording medium 31 on which the image is formed. Therefore, it is provided with a switchback path 220 and a double-sided unit 221 for inverting the front and back of the image-formed recording medium 31 and transporting the image-forming recording medium 31 to the image-forming unit 12. The switchback path 220 is provided on the upstream side of the paper ejection roller 209, and when the front and back of the recording medium 31 are reversed, the end portion of the recording medium 31 when the recording medium 31 is sent out to the paper ejection unit 400 side. Is once gripped by the paper ejection roller 209, and the paper ejection roller 209 is reversely driven to be conveyed to the switchback path 220. Then, the image is conveyed to the image forming unit 12 via the double-sided unit 221 and the paper transport path 212, and an image is formed on the back surface of the recording medium 31.
The switchback path 220 is used not only when the image is formed on both sides of the recording medium 31, but also when the image-formed surface is turned down and discharged.

The paper ejection unit 400 is provided on the side surface of the image forming unit 200. The paper ejection unit 400 includes a paper ejection tray 404 for ejecting the recording medium 31 whose image is formed by the print job.

When the print job is received and the image is formed by the image forming unit 200, the recording medium 31 sent out from the paper ejection roller 209 of the image forming unit 200 is discharged from the paper ejection roller of the paper ejection unit 400 through the paper transport path 401. It is discharged from the 403 onto the output tray 404.

Next, a schematic configuration of the digital multifunction device 1 will be described with reference to FIG.
FIG. 3 is a block diagram showing a schematic configuration of the digital multifunction device 1 of FIG.

As shown in FIG. 3, the digital multifunction device 1 includes a control unit 10, a communication unit 11, an image forming unit 12, a storage unit 13, an image processing unit 14, an image reading unit 15, a transport unit 16, a touch panel 17, and an image density adjustment. A unit 18 and a double-sided printing control unit 19 are provided.

Hereinafter, each component of the digital multifunction device 1 will be described.

The control unit 10 controls the digital multifunction device 1 in an integrated manner, and includes a CPU, RAM, ROM, various interface circuits, and the like.

The control unit 10 monitors and controls all loads such as detection of each sensor, motor, clutch, touch panel 17, etc. in order to control the operation of the entire digital multifunction device 1.

The communication unit 11 communicates with a computer, a mobile information terminal, an external information processing device, a facsimile device, or the like via a network or the like, and sends and receives various information such as mail and fax to and from these external communication devices. Is.

The image forming unit 12 is a unit that prints out the image data generated by the image processing unit 14 on the recording medium 31, and includes the LSU 1210.

The LSU 1210 is a device that forms an electrostatic latent image by irradiating the surface of the photoconductor drum 202 in a charged state with a laser beam corresponding to image information consisting of a digital signal acquired by the image reading unit 15.

The storage unit 13 is an element or a storage medium for storing information necessary for realizing various functions of the digital multifunction device 1, a control program, and the like. For example, a semiconductor element such as RAM or ROM, a hard disk, a flash storage unit, or a storage medium such as SSD is used.

The program and the data may be held in different devices, such that the area for holding the data is a hard disk drive and the area for holding the program is a flash storage unit.

The image processing unit 14 is a unit that converts the image of the original document read by the image reading unit 15 into an appropriate electric signal to generate image data.

The image reading unit 15 is a unit that detects and reads a document placed on a document setting table or a document conveyed from a paper tray and generates image data.

The transport unit 16 is a portion that transports the recording medium 31 stored in the manual feed tray, the paper feed cassette, and the document set table to the image forming unit 12.

The touch panel 17 is composed of a display panel composed of a liquid crystal panel or the like and a touch panel of a capacitance method or the like which is arranged on the display panel and detects a position where a finger is touched, and is composed of a display unit 171 and an operation unit. 172 is provided.

The display unit 171 is a part that displays various information and receives a command from the user by the touch panel function.
The display unit 171 is composed of, for example, a CRT display, a liquid crystal display, an EL display, or the like, and is a display device such as a monitor or a line display for the operating system or application software to display electronic data such as a processing state.
The control unit 10 displays the operation and status of the digital multifunction device 1 through the display unit 171.

The operation unit 172 is an interface for operating the digital multifunction device 1 and is a part that receives a command from the user.

The image density adjustment unit 18 is a portion that adjusts the image density based on the detection result of the image quality adjustment sensor 78 (FIG. 4).

The double-sided printing control unit 19 is a portion that reverses the front and back of the recording medium 31 during double-sided printing.

<Size detection processing of the recording medium 31 of the digital multifunction device 1>
Next, the size detection process of the recording medium 31 in the digital multifunction device 1 will be described with reference to FIGS. 4 to 7.
FIG. 4 is an explanatory diagram showing a schematic configuration of the visible image forming unit 51K of the digital multifunction device 1 of FIG. 1.
FIG. 5 is an explanatory diagram showing an example of detecting the length of the recording medium 31 of the digital multifunction device 1 of FIG. 1 in the main scanning direction.
FIG. 6 is an explanatory diagram showing an example of detecting the length of the recording medium 31 of the digital multifunction device 1 of FIG. 1 in the sub-scanning direction.
FIG. 7 is a flowchart showing an example of size detection processing of the recording medium 31 of the digital multifunction device 1 of FIG.

In FIG. 4, the photoconductor drum 202 rotates in the rotation direction R1 (counterclockwise direction toward the paper surface).

At the time of image formation, the surface of the photoconductor drum 202 is uniformly charged by the charger 203.

The laser writing unit 201 forms an electrostatic latent image on the surface of the photoconductor drum 202 by exposing the surface of the charged photoconductor drum 202 with a beam from the laser light source 111.
The laser beam from the laser writing unit 201 is applied to the photoconductor drum 202 through a polygon mirror (not shown) and various lenses.

The laser writing unit 201 is controlled based on the image information, and an electrostatic latent image corresponding to the image information is formed on the surface of the photoconductor drum 202.

The developer 204 develops an electrostatic latent image on the photoconductor drum 202 to form a toner image.
The electrostatic latent image formed on the photoconductor drum 202 is visualized by the developer 204 with a developer containing toner and carriers, and a toner image is formed.

As shown in FIG. 4, the developer 204 is a developing unit provided facing the photoconductor drum 202, and the developing roller 204a as a developer carrier is parallel to the rotation axis of the photoconductor drum 202. It is rotatably provided on the rotating shaft.

The developer 204 is a hollow container-shaped member made of, for example, a hard synthetic resin. As described above, the developer 204 contains the two-component developer containing the toner and the carrier, but the developer 204 may be a one-component developer containing only the toner.

The developing roller 204a is a mag roller formed by arranging magnet members having different polarities substantially alternately in the circumferential direction.
The developing roller 204a adsorbs the developing agent contained in the developing device 204 by its magnetic force.
The adsorbed developer is regulated to a predetermined amount of thickness by a developer regulating member (not shown), and is carried to a developing nip portion where the developing roller 204a and the photoconductor drum 202 are close to each other.

By applying a developing voltage, the developing roller 204a is charged to a predetermined voltage lower than the surface potential of the non-exposed portion of the photoconductor drum 202.

As a result, the toner charged to the same polarity as the charging polarity of the photoconductor drum 202 is adsorbed on the surface potential of the exposed portion of the photoconductor drum 202 to form a toner image.

On the other hand, since the surface potential of the non-exposed portion of the photoconductor drum 202 is lower than the potential of the developing roller 204a, adhesion of toner is prevented.

A voltage having the opposite polarity to that of the toner is applied to the transfer device 205, and the toner image developed on the photoconductor drum 202 is displayed on the recording medium 31 in the transfer region where the transfer device 205 and the photoconductor drum 202 are close to each other. Transcribe.

The image quality adjustment sensor 78 is a reflective sensor for shining light on a test patch formed on the photoconductor drum 202 for image quality adjustment and reading the image density of the patch from the reflected light.

As shown in FIG. 5A, the image quality adjusting sensor 78 is provided at a position on the paper transport path RT at a position separated from the center line CL in the main scanning direction by a predetermined distance D1 in the main scanning direction.

When detecting the size of the recording medium 31, the image quality adjusting sensor 78 detects the reflected light from the predetermined tip region TA of the recording medium 31A.
This is because if toner is formed on the photoconductor drum 202, erroneous recognition may occur, and it is necessary to detect the toner at the timing when the toner is not formed on the photoconductor drum 202.

Not limited to the front end region TA of the recording medium 31A, the reflected light from the predetermined rear end region RA of the recording medium 31A may be detected.

In FIG. 5A, the recording medium 31A blocks the light from the image quality adjusting sensor 78.
On the other hand, in FIG. 5B, the recording medium 31B does not block the light from the image quality adjusting sensor 78, but detects the reflected light from the photoconductor drum 202.

Further, as shown in FIG. 6A, when the length of the recording medium 31C in the main scanning direction is large enough to include the image quality adjusting sensor 78, the image quality adjusting sensor 78 also has the length of the recording medium 31C in the sub-scanning direction. Can be detected.

Specifically, the image quality adjustment sensor 78 detects the reflected light from the predetermined front end region TA and the rear end region RA of the recording medium 31C, respectively, and the time difference TD1 of the detection time thereof is a subordinate of the recording medium 31C. Calculate the length in the scanning direction.

FIG. 6B is an example of detecting the length of the recording medium 31D, which is shorter in the sub-scanning direction than the recording medium 31C of FIG. 6A.
Similarly, in the case of FIG. 6B, the image quality adjustment sensor 78 detects the reflected light from the predetermined front end region TA and the rear end region RA of the recording medium 31D, respectively, and the time difference TD2 of the detection times thereof. The length of the recording medium 31D in the sub-scanning direction is calculated from.

In this way, the image quality adjustment sensor 78 can determine whether or not the size of the recording medium 31 is larger than the predetermined reference size.

Next, the size detection process of the recording medium 31 of the digital multifunction device 1 will be described with reference to FIG. 7.

In FIG. 7, after starting printing, the control unit 10 determines in step S1 whether or not the print paper size detection setting is valid (step S1).

When the print paper size detection setting is not valid (when the determination in step S1 is No), the control unit 10 prints the recording medium 31 without detecting the size of the recording medium 31 as usual in step S2 and ejects the paper. (Step S2).
After that, the control unit 10 ends the printing process.

On the other hand, when the print paper size detection setting is valid (when the determination in step S1 is Yes), the control unit 10 causes the transfer unit 16 to start the transfer of the recording medium 31 in step S3, but the image of the recording medium 31. No formation is performed, and the lengths of the first surface region of the recording medium 31 in the main scanning direction and the sub-scanning direction are detected by the image quality adjusting sensor 78 (step S3).

Although the control unit 10 does not form an image of the recording medium 31, the image forming unit 12 may be prepared to form an image, such as by starting heating of the fixing unit 208.
By doing so, since the heating of the fixing unit 208 is started during the printing paper size detection setting, it is not necessary to wait for the temperature rise of the fixing unit 208 when the size of the recording medium 31 is appropriate.

Subsequently, in step S4, the control unit 10 determines whether or not the size of the recording medium 31 is inappropriate based on the detection result of the image quality adjustment sensor 78 (step S4).

When the size of the recording medium 31 is appropriate (when the determination in step S4 is No), the control unit 10 inverts the front and back of the recording medium 31 in step S5, and the second surface of the recording medium 31 is used as the image forming unit 12. After the image is formed, the paper is discharged to the paper ejection tray 404 (step S5).
After that, the control unit 10 ends the printing process.

On the other hand, when the size of the recording medium 31 is appropriate (when the determination in step S4 is Yes), the control unit 10 causes the image forming unit 12 to interrupt the image formation of the recording medium 31 in step S6, and the output tray 404 Paper is discharged to (step S6).

In the following step S7, the control unit 10 causes the display unit 171 to display a message to the effect that the size of the recording medium 31 should be confirmed (step S7).
After that, the control unit 10 ends the printing process.

In this way, by utilizing the existing image quality adjustment sensor 78, it is possible to realize the digital multifunction device 1 capable of reading the size of the recording medium 31 without using a dedicated reading sensor.
Further, even if the size of the recording medium 31 is inappropriate, the printing paper is not wasted because the image is not formed when the image quality adjusting sensor 78 is read.

[Embodiment 2]
<Size detection processing of the recording medium 31 of the digital multifunction device 1 of the second embodiment of the present invention>
Next, the size detection process of the recording medium 31 in the digital multifunction device 1 of the second embodiment of the present invention will be described with reference to FIG.

Since the configuration of the digital multifunction device 1 of the second embodiment is the same as the configuration of the digital multifunction device 1 of the first embodiment (FIGS. 1 to 4), the description thereof will be omitted.

FIG. 8 is a flowchart showing an example of size detection processing of the recording medium 31 of the digital multifunction device 1 of the second embodiment of the present invention.

Since the processes of steps S11 to S14 and S19 to S20 in FIG. 8 correspond to the processes of steps S1 to S4 and S6 to S7 in FIG. 7, the description thereof will be omitted.

Here, the processes of steps S15 to S18 of FIG. 8 which are not described in the first embodiment will be described.

When the paper size is appropriate in the determination in step S14 of FIG. 8 (when the determination in step S14 is No), the control unit 10 inverts the front and back of the recording medium 31 in step S15, and the second surface of the recording medium 31. Is formed by the image forming unit 12 (step S15).

In the following step S16, the control unit 10 determines whether or not the print setting is double-sided printing (step S16).

When the print setting is set to both sides (when the determination in step S16 is Yes), in step S17, the control unit 10 further inverts the front and back of the recording medium 31, and the first surface of the recording medium 31 is the image forming unit. After forming an image on No. 12, the paper is discharged to the paper ejection tray 404 (step S17).
After that, the control unit 10 ends the printing process.

On the other hand, when the print setting is set to one side (when the determination in step S16 is No), in step S18, the control unit 10 causes the image forming unit 12 to form an image on the second side of the recording medium 31, and then the control unit 10 forms an image. Paper is ejected to the output tray 404 (step S18).
After that, the control unit 10 ends the printing process.

In this way, even when single-sided or double-sided printing can be selected, by utilizing the existing image quality adjustment sensor 78, the recording medium 31 can be used without using a dedicated reading sensor and without wasting printing paper. It is possible to realize a digital multifunction device 1 that can read the size of.

[Embodiment 3]
<Size detection processing of the recording medium 31 of the digital multifunction device 1 according to the third embodiment of the present invention>
Next, the size detection process of the recording medium 31 in the digital multifunction device 1 according to the third embodiment of the present invention will be described with reference to FIG.

Since the configuration of the digital multifunction device 1 of the third embodiment is the same as the configuration of the digital multifunction device 1 of the first embodiment (FIGS. 1 to 4), the description thereof will be omitted.

FIG. 9 is a flowchart showing an example of size detection processing of the recording medium 31 of the digital multifunction device 1 of the third embodiment of the present invention.

Since the processes of steps S21, S22 and S24 to S27 in FIG. 9 correspond to the processes of steps S1 to S6 in FIG. 7, the description thereof will be omitted.

Here, the processes of steps S23 and S28 of FIG. 9, which are not described in the first embodiment, will be described.

When the print paper size detection setting is valid in step S21 (when the determination in step S21 is Yes), the control unit 10 determines whether or not the paper type set by the user in step S23 is the backing paper (when the determination in step S21 is Yes). Step S23).

When the paper type is backing paper (when the determination in step S23 is Yes), the control unit 10 causes the image forming unit 12 to interrupt the image formation of the recording medium 31 in step S27, and outputs the paper to the paper ejection tray 404. (Step S27).

In the following step S28, the control unit 10 causes the display unit 171 to display a message to confirm that the type of the recording medium 31 is the backing paper (step S28).
After that, the control unit 10 ends the printing process.

On the other hand, when the paper type is not the backing paper (when the determination in step S23 is No), the control unit 10 causes the transport unit 16 to start the transport of the recording medium 31 in step S24, but the image formation of the recording medium 31 is performed. Instead, the image quality adjusting sensor 78 detects the length in the main scanning direction in the tip region TA on the first surface of the recording medium 31 (step S24).

In this way, even when the backing paper can be used for the paper type, by utilizing the existing image quality adjustment sensor 78, a recording medium can be used without using a dedicated reading sensor and without wasting printing paper. It is possible to realize a digital multifunction device 1 capable of reading the size of 31.

Preferred embodiments of the present invention include a combination of any of the plurality of embodiments described above.
In addition to the embodiments described above, there may be various variations of the present invention. These variations should not be construed as not belonging to the scope of the present invention. The invention should include claims and equivalent meaning and all modifications within said scope.

1: Digital compound machine, 10: Control unit, 11: Communication unit, 12: Image forming unit, 13: Storage unit, 14: Image processing unit, 15: Image reading unit, 16: Transport unit, 17: Touch panel, 18: Image density adjustment unit, 19: Double-sided printing control unit, 31, 31A, 31B, 31C, 31D: Recording medium, 51K: Visible image forming unit, 78: Image quality adjustment sensor, 100: Image reading unit, 101: Original table , 102: Automatic Paper Transfer Device, 110: Light Source Unit, 111: Light Source, 112, 121, 122: Mirror, 120: Mirror Unit, 130: CCD Reading Unit, 131: Imaging Lens, 132: CCD Sensor, 171: Display Unit, 172: Operation unit, 200: Image forming unit, 201: Laser writing unit, 202: Photoreceptor drum, 203: Charger, 204: Developer, 204a: Development roller, 205: Transferter, 206: Cleaner, 207: Static eliminator, 208: Fusing unit, 209: Paper ejection roller, 210: Paper cassette, 211: Manual tray, 212, 303, 401, 405, 409: Paper transport path, 220: Switchback path, 221: Double-sided unit, 300: Paper feed unit, 301: Paper cassette, 302: Paper cassette, 301a, 302a: Call roller, 305, 411: Switchback path, 400: Paper discharge unit, 403: Paper discharge roller, 408: Call Insert roller, 404: Paper output tray, 406: Paper output roller, 1210: LSU, CL: Center line, D1: Distance, R1: Rotation direction, RA: Rear end area, RT: Paper transport path, TA: Tip area, TD1, TD2: Time difference

Claims (5)

A transport unit that transports the recording medium along the transport path,
An image forming unit that forms an image on the recording medium based on the image data,
Reflective optical sensor for adjusting image density and
An image density adjustment unit that adjusts the image density based on the detection result of the reflection type optical sensor, and an image density adjustment unit.
An image forming apparatus equipped with a control unit,
The image forming part is
Photoreceptor and
The charged part that comes into contact with the photoconductor and is charged,
An exposed portion that forms an electrostatic latent image on the photoconductor,
A developing unit that supplies toner to the photoconductor to form a toner image corresponding to the electrostatic latent image.
A transfer unit that transfers the toner image to a recording medium,
A fixing portion for heating and fixing the toner image to the recording medium by a fixing roller, and a fixing portion.
It is equipped with a double-sided printing control unit that reverses the front and back of the recording medium during double-sided printing.
The reflective optical sensor is provided so as to face the photoconductor with the transport path interposed therebetween and to irradiate light at a position separated from the center line of the transport path by a predetermined distance in the main scanning direction. Be,
When adjusting the image density, the control unit controls the charging unit, the exposure unit, and the developing unit to form a predetermined patch toner image on the photoconductor, and then controls the reflection type optical sensor. Then, the patch toner image is irradiated with light, and the image density adjusting unit is made to adjust the image density based on the reflected light.
At the time of image formation, the transport unit and the reflective optical sensor are controlled to irradiate the reflective optical sensor with light at a timing when a predetermined region of the recording medium passes, and based on the reflected light, the said After determining whether or not the size of the recording medium is appropriate, if the size of the recording medium is appropriate, the double-sided printing control unit is used to invert the recording medium, and then the image forming unit is used to form an image. On the other hand, when the size of the recording medium is not appropriate, the image forming apparatus is characterized in that the image forming portion does not form an image. The control unit controls the transport unit and the reflected light sensor to irradiate the reflected light sensor with light at a timing when a predetermined tip region of the recording medium passes, and based on the reflected light. The image forming apparatus according to claim 1, wherein it is determined whether or not the width of the recording medium in the main scanning direction is longer than a predetermined reference width. The control unit controls the transport unit and the reflection type optical sensor to irradiate the reflection type optical sensor with light at a timing when a predetermined front end region and rear end region of the recording medium pass through them. The image forming apparatus according to claim 1 or 2, wherein it is determined whether or not the width of the recording medium in the sub-scanning direction is longer than a predetermined reference width based on the time difference of the reflected light. Further provided with an operation unit that accepts the setting of whether or not the size of the recording medium should be determined by the reflective optical sensor and the setting of the type of the recording medium including the backing paper.
The control unit is an image forming unit when the type of the recording medium set by the user is a backing paper when the setting for determining the size of the recording medium by the reflection type optical sensor is effective. The image forming apparatus according to any one of claims 1 to 3, wherein the image forming is interrupted. The control unit controls the transport unit and the reflection type optical sensor to start determining whether or not the size of the recording medium is appropriate, and causes the fixing unit to start heating the fixing roller. The image forming apparatus according to any one of 1 to 4.

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