JP2022112111A - Image forming system and control method - Google Patents

Abstract

An object of the present invention is to uniformly dry black ink and color ink in a short time while preventing an excessive temperature rise. Kind Code: A1 An image forming system includes a printer and a drying device. A near-infrared heat source 52 that radiates near-infrared rays to a part, and a mid-infrared heat source 62 that radiates mid-infrared rays to a section downstream in the conveying direction Y from the near-infrared heat source 52 in the conveying section. It is characterized by having [Selection drawing] Fig. 3

Description

The present invention relates to an image forming system and control method for drying ink ejected onto a sheet.

When an image is formed by an inkjet method, it is necessary to quickly dry the ink ejected onto the sheet in order to prevent disturbance of the image, deformation of the sheet, sticking of the sheet, and the like. As an example of a technique for drying ink, a device using infrared rays of two wavelength ranges is known. For example, in Patent Document 1, a first infrared heating unit that irradiates infrared rays having a maximum wavelength within the absorption wavelength band of water, and a first infrared heating unit arranged downstream in the conveying direction and within the absorption wavelength band of the solvent It is proposed to use a second infrared heating unit that emits infrared rays having a maximum wavelength in the. Patent Document 2 proposes controlling the heating means to emit near-infrared rays during monochrome recording, and controlling the heating means to emit mid-infrared rays or far-infrared rays during color recording.

JP 2013-39721 A JP 2016-55515 A

However, in the configuration proposed in Patent Document 1, the infrared rays having the maximum wavelengths in the absorption wavelength bands of water and solvent are the mid-infrared rays and the far-infrared rays, respectively. In the configuration proposed in Patent Document 2, since mid-infrared rays or far-infrared rays are used during color recording, it takes time for water to evaporate. However, since the change in wavelength is delayed with respect to the change in voltage, speeding up the drying process is hindered. Also, it is known that when near-infrared rays are used, the temperature rise rate of black ink is much faster than that of color ink. Therefore, in the configuration proposed in Japanese Patent Application Laid-Open No. 2002-200011, in the case of a printed matter in which a monochrome image and a color image are mixed, there is a possibility that the temperature of the monochrome image portion may rise excessively. Reducing the irradiation time to prevent excessive temperature rise results in insufficient drying of the color image areas.

SUMMARY OF THE INVENTION In view of the above circumstances, it is an object of the present invention to provide a drying device and an image forming system that can uniformly dry black ink and color ink in a short time while suppressing an excessive temperature rise. and

In order to solve the above problems, an image forming system according to the present invention includes an inkjet recording device and a drying device, and the inkjet recording device conveys a sheet along a conveying path leading to the drying device. and an image forming unit that ejects ink onto the sheet conveyed by the conveying unit, and the drying device includes an endless belt that conveys the sheet conveyed from the inkjet recording device. a transport unit, a near-infrared heat source that emits near-infrared rays to a portion of a transport section in the transport unit, and a portion of the transport section upstream or downstream in the transport direction of the transport unit from the near-infrared heat source. and a mid-infrared heat source that radiates mid-infrared rays to the section (first invention).

The mid-infrared heat source may be provided downstream of the near-infrared heat source in the conveying direction (second invention).

The belt includes a first belt facing the near-infrared heat source and a second belt facing the mid-infrared heat source, and the conveying unit separates the first belt and the second belt. (third invention).

The mid-infrared heat source is provided upstream of the near-infrared heat source in the conveying direction, and the belt includes a first belt facing the near-infrared heat source and a second belt facing the mid-infrared heat source. and a belt, and the transport unit may drive the first belt at a faster speed than the second belt (fourth invention).

Further, the control method according to the present invention is provided when the jam of the sheet is detected in the image forming system according to the second or third invention and the sheet is detected in the area facing the near-infrared heat source. Secondly, the belt is driven until the sheet is no longer detected in the area facing the near-infrared heat source (a fifth invention).

In a fifth aspect, when the sheet jam is detected in the image forming system and the sheet is detected in a region facing the near-infrared heat source, the near-infrared heat source is turned off, The belt is driven until the sheet is no longer detected in the area facing the near-infrared heat source, and then a predetermined time has passed since the near-infrared heat source was turned off, or the near-infrared heat source The belt may be stopped when the temperature of is below a predetermined temperature (sixth invention).

Further, in the control method according to the present invention, when the jam of the sheet is detected in the image forming system according to the third invention and the sheet is detected in the area facing the near-infrared heat source, the When the near-infrared heat source is turned off, the first belt and the second belt are driven until the sheet is no longer detected in the area facing the near-infrared heat source, and then the near-infrared heat source is turned off. or when the temperature of the near-infrared heat source becomes equal to or lower than a predetermined temperature, the first belt is stopped (a seventh invention).

In a control method according to a seventh aspect of the invention, after driving the first belt and the second belt until the sheet is no longer detected in a region facing the near-infrared heat source, the second belt is stopped; After that, when the predetermined time has passed since the near-infrared heat source was turned off, or when the temperature of the near-infrared heat source becomes equal to or lower than the predetermined temperature, the first belt may be stopped. Good (eighth invention).

In the control method according to any one of the fifth to eighth inventions, when the jam of the sheet is detected in the image forming system and the sheet is detected in the area facing the near-infrared heat source, The belt may be driven at a speed higher than before the sheet jam is detected (ninth invention).

In the control method according to any one of the fifth to ninth inventions, when the sheet jam is detected in the image forming system and the sheet is detected in the area facing the near-infrared heat source, Conveyance of the sheet may be stopped on the upstream side in the conveying direction of the conveying unit (a tenth invention).

In the control method according to any one of the fifth to tenth inventions, only the mid-infrared heat source may be turned on for the sheet on which only a monochrome image is printed (eleventh invention).

In the control method according to any one of the fifth to eleventh inventions, the mid-infrared heat source and the near-infrared heat source may be turned on for the sheet on which only a color image is printed (a twelfth invention). ).

In the control method according to any one of the fifth to twelfth inventions, the mid-infrared heat source and the near-infrared heat source are turned on for the sheet on which the monochrome image and the color image are mixed, and only the color image is turned on. The duty ratio of the near-infrared heat source may be lowered more than the case (a thirteenth invention).

In the control method according to any one of the fifth to thirteenth inventions, when the sheet is plain paper or inkjet paper, only the mid-infrared heat source may be turned on (fourteenth invention).

In the control method according to any one of the fifth to tenth inventions, only the mid-infrared heat source may be turned on when the ratio of the area occupied by the ink dots to the area of the sheet is equal to or less than a threshold value ( 15th invention).

According to the present invention, black ink and color ink can be dried uniformly and in a short time while preventing an excessive temperature rise.

1 is a perspective view showing the appearance of an image forming system according to a first embodiment of the invention; FIG. 1 is a front view schematically showing an internal configuration of an image forming system 100 according to a first embodiment of the invention; FIG. It is a front view which shows typically the internal structure of the drying apparatus 120 which concerns on 1st Embodiment of this invention. FIG. 2 is a block diagram showing the electro-drama configuration of the drying device 120 according to the first embodiment of the present invention; 4 is a flow chart showing the procedure of transport control according to the first embodiment of the present invention; 4 is a flowchart showing the procedure of selection processing according to the first embodiment of the present invention; It is a front view which shows typically the internal structure of the drying apparatus which concerns on 2nd Embodiment of this invention. FIG. 11 is a flow chart showing the procedure of transport control according to the second embodiment of the present invention; FIG. It is a front view which shows typically the internal structure of the drying apparatus which concerns on the 2nd modification of 2nd Embodiment of this invention.

[Configuration of the first embodiment]
A drying apparatus 120 and an image forming system 100 according to the first embodiment of the present invention will be described below with reference to the drawings.

First, the overall configuration of the image forming system 100 according to the first embodiment will be described. FIG. 1 is a perspective view showing the appearance of an image forming system 100. As shown in FIG. FIG. 2 is a front view schematically showing the internal configuration of the image forming system 100. As shown in FIG. In the following description, the front side of the image forming system 100 is defined as the front side of the paper surface of FIG. In each figure, U, Lo, L, R, Fr, and Rr indicate up, down, left, right, front, and rear, respectively.

The image forming system 100 includes a paper feeding device 110 , a printer 1 (an example of an inkjet recording device), a drying device 120 and a post-processing device 130 . The paper feeder 110 includes a large-capacity paper feed deck 84 capable of accommodating thousands of sheets S, and supplies the sheets S to the printer 1 . The printer 1 forms an image on the sheet S using an inkjet method. The drying device 120 heats and dries the ink ejected onto the sheet S. As shown in FIG. The post-processing device 130 performs post-processing on the sheet S such as punching, stapling, and folding.

The printer 1 has a rectangular parallelepiped housing 3 . In the lower portion of the housing 3 , a paper feed cassette 4 containing sheets S such as plain paper and coated paper, and a paper feed roller 5 for feeding the sheet S from the paper feed cassette 4 are provided. Above the paper feeding cassette 4, a conveying unit 7 is provided that attracts the sheet S and conveys it in the Y direction. An imaging unit 6 having a plurality of inkjet heads (not shown) is provided above the transport unit 7 . At the upper left part of the housing 3, there is provided a sheet ejection port 9 through which the sheet S on which an image is formed is ejected. An ink container 20 for supplying water-based ink to the image forming unit 6 is provided on the left side of the paper feed cassette 4 .

Inside the housing 3 , a transport path 10 is provided that extends from the paper feed cassette 4 through the gap between the transport unit 7 and the image forming section 6 to the paper exit 9 . The transport path 10 is formed by plate-like members (not shown) facing each other with a gap through which the sheet S passes. is provided. A registration roller pair 18 is provided on the upstream side in the transport direction Y of the imaging unit 6 .

The conveying unit 7 includes an endless belt 21 provided with a large number of ventilation holes (not shown) and wound around a plurality of rollers 22, and a support provided with a large number of ventilation holes and having an upper surface in contact with the inner surface of the belt 21. A plate 23 and a suction unit 24 that sucks the sheet S to the belt 21 by sucking air through the ventilation holes of the support plate 23 . One of the plurality of rollers 22 is driven by a motor (not shown) to rotate the belt 21 and convey the sheet S attracted to the belt 21 in the Y direction.

The image forming section 6 includes four sets of head units, which eject yellow, black, cyan, and magenta inks, respectively. Ink containers 20 filled with yellow, black, cyan, and magenta inks are connected to the head unit. The head unit includes a plurality of inkjet heads arranged in a zigzag pattern. The inkjet head includes a housing and a nozzle plate provided on the bottom of the housing. The nozzle plate has a large number of nozzles arranged in the front-rear direction, and each nozzle has a discharge port provided on the lower surface of the nozzle plate. Each nozzle is provided with a piezoelectric element, and a drive circuit for driving the piezoelectric element is provided inside the housing.

The control unit 2 includes a processor and memory. The processor is, for example, a CPU (Central Processing Unit). The memory includes storage media such as ROM (Read Only Memory), RAM (Random Access Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). The processor performs various processes by reading and executing control programs stored in the memory. Note that the control unit 2 may be implemented by an integrated circuit that does not use software.

An operation panel 19 is provided on the right rear portion of the upper surface of the housing 3 (see FIG. 1). The operation panel 19 includes a display panel, a touch panel superimposed on the display surface of the display panel, and a keypad adjacent to the display panel. The control unit 2 displays a screen representing an operation menu of the printer 1 on the display panel, and controls each unit of the printer 1 according to operations detected by the touch panel and keypad.

A basic image forming operation of the printer 1 is as follows. When an image forming job is input to the printer 1 from an external computer or the like, the paper feed roller 5 feeds the sheet S from the paper feed cassette 4 to the transport path 10, and the registration roller pair 18 whose rotation is stopped causes the sheet S to skew. Correct the line. When the registration roller pair 18 feeds the sheet S to the conveying unit 7 at a predetermined timing, the conveying unit 7 causes the belt 21 to adsorb the sheet S and conveys it in the Y direction. When the control unit 2 supplies gradation data corresponding to each nozzle of the ink jet head to the drive circuit in synchronization with the conveyance of the sheet S, the drive circuit supplies a drive signal corresponding to the gradation data to the piezoelectric element, thereby causing the nozzle to rotate. An image is formed on the sheet S by ejecting ink droplets from the . The conveying unit 7 discharges the sheet S on which the image is formed through the discharge port 9 .

Next, the configuration of the image forming system 100 will be described in detail. The image forming system 100 includes an inkjet recording device (printer 1 ) and a drying device 120 . The inkjet recording apparatus includes a conveying unit (conveying roller pair 17, registration roller pair 18, conveying unit 7, conveying roller pair 97) that conveys the single sheet S along the conveying path 10 leading to the drying device 120, and a conveying unit and an image forming unit 6 that ejects ink onto the sheet S conveyed by the image forming unit 6 . The drying device 120 includes a transport unit 40 including an endless belt that transports the sheet S transported from the inkjet recording apparatus, a near-infrared heat source 52 that radiates near-infrared rays to a portion of the transport section in the transport unit 40, and a mid-infrared heat source 62 that radiates mid-infrared rays to a section downstream in the transport direction Y of the transport unit 40 from the near-infrared heat source 52 in the transport section.

[Paper feed section]
First, the paper feed unit will be described. The paper feed cassette 4 of the printer 1 and the paper feed deck 84 of the paper feed device 110 are examples of the paper feed unit.

[Paper Cassette]
The paper feed cassette 4 must satisfy the following requirements. First, it is necessary to position the sheet S at a predetermined position in the direction orthogonal to the transport direction Y of the transport path 10 . In addition, it is necessary to position the sheet S at a position where the sheet feeding roller 5 can come into contact. Moreover, it is necessary to prevent the sheets S stacked in the paper feed cassette 4 from collapsing. Therefore, the sheet feeding cassette 4 is provided with a cursor (not shown) that positions the sheet S at a predetermined position by contacting the edge of the stacked sheet S. As shown in FIG. Also, in order to supply sheets S of various sizes, it is possible to position the cursor at a predetermined position for each size.

As an example, in the present embodiment, the maximum size of the sheets S that can be supplied by the paper feeding cassette 4 is A3 size, and the minimum size is A6 size. The printer 1 includes two paper feed cassettes 4, one of which accommodates A3 size sheets SL, and the other accommodates A6 size sheets SS. In both cases, the sheet S is accommodated in the paper feed cassette 4 with the long side of the sheet S parallel to the conveying direction Y. As shown in FIG. Therefore, the maximum length Lmax in the transport direction Y of the sheets S that can be supplied by the paper feed cassette 4 is the length of the long side of A3 size (420 mm), and the minimum length Lmin is the length of the long side of A6 size ( 148 mm).

[Paper feeder]
The sheet feeding device 110 includes a rectangular parallelepiped housing 83 , a sheet feeding deck 84 in which sheets S are stored, and sheet feeding rollers 85 for feeding the sheets S from the sheet feeding deck 84 . A discharge port 89 is provided on the left side of the housing 83, and a transport path 90 is provided from the paper feed deck 84 to the discharge port 89. As shown in FIG. The transport path 90 is formed by plate-like members (not shown) facing each other with a gap through which the sheet S passes. is provided. The transport path 90 is connected to the transport path 10 via the paper discharge port 89 and the paper feed port 11 of the printer 1 .

As with the paper feed cassette 4, the paper feed deck 84 has a cursor (not shown), and the maximum size of the sheets S that can be supplied by the paper feed deck 84 is A3 size, and the minimum size is A6 size. The sheet feeding device 110 includes two sheet feeding decks 84, one of which accommodates A3 size sheets SL and the other of which accommodates A6 size sheets SS. In both cases, the sheet S is stored in the sheet feed deck 84 with the long side of the sheet S parallel to the conveying direction Y. As shown in FIG. Therefore, the maximum length Lmax in the transport direction Y of the sheets S that can be supplied by the sheet feeding deck 84 is the length of the long side of A3 size (420 mm), and the minimum length Lmin is the length of the long side of A6 size ( 148 mm).

In this embodiment, the maximum length Lmax and the minimum length Lmin of the sheets S that can be supplied by the sheet feed cassette 4 are the maximum lengths of the sheets S that can be supplied by the sheet feeding deck 84 in the transport direction Y. length Lmax and minimum length Lmin, but they do not have to be common. In this case, the maximum length Lmax in the transport direction Y of the sheets S that can be supplied by the sheet feeding unit is the longer of the maximum length Lmax of the sheet feeding cassette 4 and the maximum length Lmax of the sheet feeding deck 84 . Also, the minimum length Lmin in the transport direction Y of the sheets S that can be supplied by the sheet feeding unit is the shorter of the minimum length Lmin of the sheet feeding cassette 4 and the minimum length Lmin of the sheet feeding deck 84 .

[Drying device]
Next, the drying device 120 will be described. FIG. 3 is a front view schematically showing the internal configuration of the drying device 120. As shown in FIG. FIG. 4 is a block diagram illustrating the electrodraft configuration of the dryer 120. As shown in FIG.

Specifically, the drying device 120 includes a rectangular parallelepiped housing 31 . A transport unit 40 is provided slightly above the center in the housing 31 , and a first drying section 50 and a second drying section 60 are provided above the transport unit 40 . The housing 31 has a paper feed port 32 on the right side and a paper discharge port 33 on the left side. A transport path 34 leading to the port 33 is provided. A transport roller pair 35 is provided on the downstream side in the transport direction Y of the transport unit 40 . The right end of the transport unit 40 protrudes from the paper feed port 32 to the outside of the housing 31 , and when the right end of the transport unit 40 is inserted into the paper discharge port 9 of the printer 1 , the transport path 10 of the printer 1 and the A transport path 34 of the drying device 120 is connected (see FIG. 2).

A reversing paper discharge port 37 is provided above the paper feed port 32 , and a reverse paper feed port 12 is provided above the paper discharge port 9 of the printer 1 . The reverse transport path 34R branches upward from the transport path 34 downstream of the transport unit 40 in the transport direction Y, and is connected to the reverse transport path 10R of the printer 1 via the reverse paper discharge port 37 and the reverse paper feed port 12. ing. The reverse transport path 10</b>R joins the transport path 10 on the upstream side in the transport direction Y of the registration roller pair 18 . The reversing conveying paths 34R and 10R are formed of plate-shaped members facing each other with a gap for allowing the sheet S to pass therethrough. (not shown). A switchback section is provided in the reversing conveying path 34R, and the sheet S that has been reversed in the switchback section is sent to the conveying path 10 via the reversing conveying path 10R.

[Transport unit]
The conveying unit 40 is provided with a large number of ventilation holes (not shown), and includes an endless belt 41 wound around a plurality of (two in this embodiment) rollers 42 and a large number of ventilation holes (not shown). A support plate 43 is provided and has an upper surface in contact with the inner peripheral surface of the belt 41 , and a suction portion 44 sucks the sheet S to the belt 41 by sucking air through the ventilation holes of the support plate 43 . One of the rollers 42 is driven by the motor 45 to rotate the belt 41 counterclockwise, and the sheet S attracted to the belt 41 is conveyed in the Y direction. The sheet S is conveyed by being attracted to a planar section (hereinafter referred to as a conveying section) on the upper portion of the belt 41 wound around the two rollers 42 . Both ends of the transport section in the transport direction Y are located directly above the centers of the axes of the two rollers 42 .

[First drying section]
The first drying section 50 has a rectangular parallelepiped housing 51 with an open bottom. The housing 51 accommodates a plurality of near-infrared heat sources 52 that emit near-infrared rays (with a wavelength of 2 μm or less). The near-infrared heat sources 52 are rod-shaped with the front-rear direction as the longitudinal direction, are arranged at regular intervals in the transport direction Y, and are fixed to the housing 51 at both front and rear ends. The near-infrared heat source 52 is a halogen heater, a carbon heater, an infrared LED (Light Emitting Diode), a ceramic heater, or the like. Above each near-infrared heat source 52, a reflector 53 is provided facing the transport path 34 with the near-infrared heat source 52 interposed therebetween. The reflecting plate 53 is a plate whose longitudinal direction is the front-rear direction, and the lower surface of the reflecting plate 53 forms a concave surface in which the cross section perpendicular to the front-rear direction draws an upwardly convex parabola.

[Second drying section]
The second drying section 60 has a rectangular parallelepiped housing 61 with an open bottom. The housing 61 accommodates a plurality of mid-infrared heat sources 62 that emit mid-infrared rays (wavelength: 2 to 4 μm). The mid-infrared heat sources 62 are bar-shaped with the front-rear direction as the longitudinal direction, are arranged at equal intervals in the transport direction Y, and are fixed to the housing 61 at both front and rear ends. The mid-infrared heat source 62 is a halogen heater, a carbon heater, an infrared LED, a ceramic heater, or the like. A reflector 63 having the same shape as the reflector 53 is provided above each mid-infrared heat source 62 .

Note that the division of wavelengths into the near-infrared rays and the middle-infrared rays is only an example.

The first drying section 50 is provided closer to the paper feed port 32 than the center in the left-right direction of the transport section of the transport unit 40 . The second drying section 60 is provided downstream in the transport direction Y from the first drying section 50 . A section on the upstream side of the end of the first drying section 50 on the downstream side in the conveying direction Y of the conveying section is called an upstream section US, and a section on the conveying direction Y downstream side of the first drying section 50 is called a downstream section DS. call. The first drying section 50 faces part or all of the upstream section US, and the second drying section 60 faces part or all of the downstream section DS. The length LD of the downstream section DS is equal to or greater than the maximum length Lmax of the sheet S that can be fed by the sheet feeder.

[Sheet detector]
The drying device 120 includes a sheet detection section 36 that detects the sheet S in a region facing the near-infrared heat source 52 . The sheet detection units 36 are provided at a plurality of locations in the transport direction Y and at a plurality of locations in a direction intersecting the transport direction Y in the area facing the near-infrared heat source 52, and are located in areas A3 to A6 facing the near-infrared heat source 52. The sheet S up to is detected. The sheet detection unit 36 is, for example, a reflective optical sensor, detects the sheet S by capturing reflected light from the sheet S on the belt 41 , and outputs a detection signal indicating the presence or absence of the sheet S to the control unit 30 . do.

[Clogging detector]
The drying device 120 includes a jam detector 38 that detects a jam of the sheet S in the conveying path 34 . The jam detectors 38 are provided at a plurality of locations in the transport direction Y. As shown in FIG. The jam detection unit 38 is, for example, a reflective optical sensor, detects the sheet S by capturing reflected light from the sheet S on the conveying path 34, and sends a detection signal indicating the presence or absence of the sheet S to the control unit 30. Output.

[Control section]
The control unit 30 includes a processor and memory. The processor is, for example, a CPU (Central Processing Unit). The memory includes storage media such as ROM (Read Only Memory), RAM (Random Access Memory), and EEPROM (Electrically Erasable Programmable Read Only Memory). The processor performs various processes by reading and executing control programs stored in the memory. Note that the control unit 30 may be implemented by an integrated circuit that does not use software. The motor 45 , the near-infrared heat source 52 , and the mid-infrared heat source 62 of the transport unit 40 are controlled by the controller 30 . Also, the control unit 30 communicates with the control unit 2 of the printer 1 . The control unit 30 determines that the jam of the sheet S is detected when the sheet S is detected by any of the jam detection units 38 continuously for a predetermined time or longer.

The transport path 10 of the printer 1 and the transport path 90 of the paper feeder 110 are provided with a jam detector 13 similar to the jam detector 38 of the drying device 120 (see FIG. 2). The clogging detection unit 13 outputs a detection signal indicating to the control unit 2 . The control unit 2 transmits a detection signal indicating the jam of the sheet S to the control unit 30 of the drying device 120 when the sheet S is detected by any of the jam detection units 13 continuously for a predetermined time or longer.

[Operation of the first embodiment]
Next, operation of the image forming system 100 according to the first embodiment will be described. FIG. 5 is a flow chart showing the procedure of transport control. When a print job is input to the printer 1, the control unit 30 executes transport control.

First, the control unit 30 starts driving the belt 41 at the first speed (step S01). The first speed is the normal transport speed of transport unit 40 .

Next, the control unit 30 selects and turns on a heat source (step S02). Specifically, the controller 2 of the printer 1 transmits page information included in the print job to the controller 30 of the drying device 120 . The page information includes the material of the sheet S (plain paper, inkjet paper, etc.), the ratio of the area occupied by the ink dots to the area of the sheet S excluding the margin (hereinafter referred to as the ink area ratio), and the color of the image. (monochrome image only, color image only, mixed monochrome image and color image), etc. are shown in page order. The control unit 30 develops the page information in the RAM, refers to the page information corresponding to the sheet S passing through the conveying section, and executes the selection process.

FIG. 6 is a flowchart showing the procedure of selection processing. In step S02, the control unit 30 selects a heat source to be lit according to the flow chart of FIG.

First, the control unit 30 determines whether the material of the sheet S is plain paper or inkjet paper (step S31). Since plain paper or inkjet paper has high ink absorbability, only mid-infrared rays are used in this embodiment regardless of the ink area ratio or the color of the image. That is, when it is determined that the material is plain paper or inkjet paper (step S31: YES), the control unit 30 turns on only the mid-infrared heat source 62 (step S41), and ends the selection process. On the other hand, when it is determined that the material is neither plain paper nor inkjet paper (step S31: NO), the control section 30 proceeds to the process of step S33.

In step S33, the controller 30 determines whether the ink area ratio is equal to or less than the threshold. The threshold value is the ink area ratio that can be dried at a normal transport speed using only mid-infrared rays, regardless of the color of the image, and is determined by experiment. When determining that the ink area ratio is equal to or less than the threshold (step S33: YES), the control unit 30 turns on only the mid-infrared heat source 62 (step S41), and ends the selection process. On the other hand, if it is determined that the ink area ratio is greater than the threshold (step S33: NO), the control section 30 proceeds to the process of step S35.

In step S35, the control section 30 determines whether or not the image is only a monochrome image. In the case of only a monochrome image, the use of near-infrared rays may cause an excessive temperature rise. Therefore, in this embodiment, only mid-infrared rays are used. That is, when it is determined that the image is a monochrome image (step S35: YES), the control unit 30 turns on only the mid-infrared heat source 62 (step S41), and ends the selection process. On the other hand, when it is determined that the image is not only a monochrome image (step S35: NO), the control section 30 proceeds to the process of step S37.

In step S37, the control section 30 determines whether or not the image is only a color image. In the case of only color images, the use of near-infrared rays does not cause excessive temperature rise, so in this embodiment, near-infrared rays and middle-infrared rays are used. That is, when it is determined that the image is a color image (step S37: YES), the control unit 30 turns on the near-infrared heat source 52 and the mid-infrared heat source 62 (step S45), and ends the selection process. . On the other hand, when it is determined that the image is not only a color image (step S37: NO), the control section 30 proceeds to the process of step S39.

In step S39, the control section 30 determines whether or not a monochrome image and a color image are mixed. When a monochrome image and a color image are mixed, it is more efficient to use near-infrared rays and mid-infrared rays together. use near-infrared rays. That is, when it is determined that the monochrome image and the color image are mixed (step S39: YES), the control unit 30 turns on the mid-infrared heat source 62, lowers the duty ratio than usual, and turns on the near-infrared heat source. 52 is turned on (step S43), and the selection process ends. On the other hand, when it is determined that the monochrome image and the color image are not mixed (step S39: NO), the controller 30 turns on only the mid-infrared heat source 62 (step S41).

When the processing of step S02 is completed, the control section 30 determines whether or not the print job has ended (step S03). Specifically, when receiving a control signal indicating the end of the print job from the control unit 2 of the printer 1, the control unit 30 determines that the print job has ended (step S03: YES), and ends the transport control. do. On the other hand, if the control signal indicating the end of the print job is not received, the control unit 30 determines that the print job has not ended (step S03: NO), and proceeds to the process of step S05.

In step S05, the control unit 30 determines whether or not jamming of the sheet S has been detected. Specifically, when no jam is detected by any of the jam detection units 38, and when a detection signal indicating that the jam is detected is not received from the control unit 2 of the printer 1 (step S05 : NO), the control unit 30 repeats the processes after step S02. On the other hand, if a jam is detected by any of the jam detectors 38, or if a detection signal indicating that a jam has been detected is received from the controller 2 of the printer 1 (step S05: YES), the controller 30 shifts to the process of step S07.

In step S<b>07 , the control unit 30 determines whether or not the sheet S is detected in the area facing the near-infrared heat source 52 . Specifically, when the sheet S is not detected by any of the sheet detection units 36, the control unit 30 determines that the sheet S is not detected in the area facing the near-infrared heat source 52 (step S07). : NO), the process proceeds to step S19. In step S19, the control unit 30 turns off the heat source that was turned on in step S02, transmits a control signal indicating interruption of the print job to the printer 1, stops driving the belt 41, and proceeds to the process of step S17. . The control unit 2 of the printer 1 that has received the control signal indicating the suspension of the print job suspends the print job. Due to the interruption of the print job, the conveyance of the sheet S in the printer 1 and the sheet feeding device 110 is stopped. Note that when a jam is detected in the printer 1 or the paper feeder 110 , the control unit 2 of the printer 1 interrupts the print job regardless of whether or not there is a control signal from the control unit 30 of the drying device 120 .

On the other hand, if the sheet S is detected by any of the sheet detection units 36, the control unit 30 determines that the sheet S has been detected in the area facing the near-infrared heat source 52 (step S07: YES). The process proceeds to S09.

In step S09, the control unit 30 turns off the heat source that was turned on in step S02, transmits a control signal indicating interruption of the print job to the printer 1, and changes the speed of the belt 41 to a second speed higher than the first speed. raise. The control unit 2 of the printer 1 that has received the control signal indicating the suspension of the print job suspends the print job. Due to the interruption of the print job, the conveyance of the sheet S in the printer 1 and the sheet feeding device 110 is stopped. Note that when a jam is detected in the printer 1 or the paper feeder 110 , the control unit 2 of the printer 1 interrupts the print job regardless of whether or not there is a control signal from the control unit 30 of the drying device 120 . Further, in the drying device 120 , when the transport roller pair 35 is provided upstream in the transport direction Y from the transport unit 40 , the controller 30 also stops the transport roller pair 35 . That is, when the jam of the sheet S is detected in the image forming system 100 and the sheet S is detected in the area facing the near-infrared heat source 52 , the controller 30 controls the upstream of the conveying unit 40 in the conveying direction Y. stop the conveyance of the sheet S on the side.

Next, the control unit 30 determines whether or not the sheet S is detected in the area facing the near-infrared heat source 52 (step S11). Here, the fact that the sheet S is detected in the area facing the near-infrared heat source 52 means that the sheet S detected in step S<b>07 is passing through the area facing the near-infrared heat source 52 . When it is determined that the sheet S is detected in the area facing the near-infrared heat source 52 (step S11: YES), the control section 30 repeats the process of step S11. On the other hand, when it is determined that the sheet S is not detected in the area facing the near-infrared heat source 52 (step S11: NO), the control section 30 proceeds to the process of step S13.

In step S13, the controller 30 determines whether or not a predetermined time has passed since the near-infrared heat source 52 was turned off. The predetermined time is the time required for the temperature of the near-infrared heat source 52 to decrease to such an extent that the sheet S does not burn when the sheet S stays in the area facing the near-infrared heat source 52 . When determining that the predetermined time has not elapsed (step S13: NO), the control unit 30 repeats the process of step S13. On the other hand, when determining that the predetermined time has passed (step S13: YES), the control unit 30 proceeds to the process of step S15.

At step S<b>15 , the control unit 30 stops driving the belt 41 . Next, the control unit 30 determines whether or not the print job has been restarted (step S17). Specifically, when the user removes the jammed sheet S and the jam detection units 38 and 13 no longer detect the jam of the sheet S, the control unit 2 of the printer 1 displays a screen for accepting an operation to restart the print job. is displayed on the operation panel 19. When the user performs an operation for resuming the print job, the control unit 2 transmits a control signal indicating resumption of the print job to the control unit 30 of the drying device 120, and then resumes the print job. If the control signal indicating the restart of the print job is not received, the control unit 30 determines that the print job has not been restarted (step S17: NO), and repeats the process of step S17. On the other hand, when the control signal indicating the restart of the print job is received, the control unit 30 determines that the print job has been restarted (step S17: YES), and repeats the processes after step S01.

According to the image forming system 100 according to the present embodiment described above, the near-infrared heat source 52 that radiates near-infrared rays to a portion of the transportation section in the transportation unit 40 and the near-infrared heat source 52 in the transportation section and a mid-infrared heat source 62 that radiates mid-infrared rays to a section on the downstream side in the transport direction Y of the transport unit 40 . According to this configuration, the near infrared rays and the middle infrared rays can be selectively used or used together according to conditions such as the material of the sheet S, the ink area ratio, and the color of the image. Also, in the method of changing the wavelength by controlling the voltage, the wavelength change is delayed, but in the present invention, the lighting timings of the near-infrared heat source 52 and the mid-infrared heat source 62 can be controlled individually. Therefore, the black ink and the color ink can be dried uniformly and in a short time while preventing an excessive temperature rise.

Further, according to the image forming system 100 according to the present embodiment, when the jam of the sheet S is detected, the sheet S facing the near-infrared heat source 52 is reliably moved to the downstream side in the conveying direction Y from the near-infrared heat source 52 . Therefore, it is possible to suppress excessive temperature rise of the sheet S due to the near-infrared rays.

Further, according to the image forming system 100 according to the present embodiment, when the jam of the sheet S is detected in the image forming system 100 and the sheet S is detected in the area facing the near-infrared heat source 52, the near infrared heat source 52 is detected. Since the belt 41 is driven until the sheet S is no longer detected in the area facing the infrared heat source 52 , it is possible to prevent the sheet S from staying in the area facing the near-infrared heat source 52 . Therefore, it is possible to prevent an excessive temperature rise in the monochrome image portion.

Further, according to the image forming system 100 according to the present embodiment, when the jam of the sheet S is detected in the image forming system 100 and the sheet S is detected in the area facing the near-infrared heat source 52, the near infrared heat source 52 is detected. When the infrared heat source 52 is turned off, the belt 41 is driven until the sheet S is no longer detected in the area facing the near-infrared heat source 52, and a predetermined time has elapsed since the near-infrared heat source 52 was turned off. Furthermore, since the belt 41 is stopped, when the sheet S enters the area after the sheet S is no longer detected in the area facing the near-infrared heat source 52, excessive temperature rise in the monochrome image portion can be suppressed. can be done.

Further, according to the image forming system 100 according to the present embodiment, when the jam of the sheet S is detected in the image forming system 100 and the sheet S is detected in the area facing the near-infrared heat source 52, the sheet Since the belt 41 is driven at a speed higher than before the jam of S is detected, the temperature rise of the sheet S facing the near-infrared heat source 52 can be suppressed.

Further, according to the image forming system 100 according to the present embodiment, when the jam of the sheet S is detected in the image forming system 100 and the sheet S is detected in the area facing the near-infrared heat source 52, the conveying Since the transport of the sheet S on the upstream side in the transport direction Y of the unit 40 is stopped, it is possible to prevent the sheet S from entering the region facing the near-infrared heat source 52 .

[Modification of First Embodiment]
In the first embodiment, the belt 41 is stopped when a predetermined time has passed since the near-infrared heat source 52 was turned off, but the temperature of the near-infrared heat source 52 became equal to or lower than the predetermined temperature. It may also be configured to stop the belt 41 in some cases. The predetermined temperature is a temperature at which the sheet S is not scorched when the sheet S stays in the area facing the near-infrared heat source 52 . A temperature sensor that measures the temperature of the near-infrared heat source 52 is provided, and the control unit 30 stops the belt 41 when the measured temperature becomes equal to or lower than a predetermined temperature. According to this configuration, even if the sheet S enters the area facing the near-infrared heat source 52 after the sheet S is no longer detected, it is possible to prevent an excessive temperature rise of the sheet S.

[Other Modifications]
In the above-described embodiment, the control unit 30 increases the speed of the belt 41 from the first speed to the second speed in step S09 of the transport control shown in FIG. may be maintained at the first speed.

Step S13 in the above embodiment may be omitted.

[Second embodiment]
Next, regarding the drying device 121 and the image forming system 100 according to the second embodiment of the present invention, differences from the first embodiment will be described. The belts 41 include a first belt 71 facing the near-infrared heat source 52 and a second belt 72 facing the mid-infrared heat source 62. The conveying unit 40 includes the first belt 71 and the second belt 72. can be driven individually. When the image forming system 100 detects the jam of the sheet S and also detects the sheet S in the area facing the near-infrared heat source 52 , the control unit 30 turns off the near-infrared heat source 52 to turn off the near-infrared heat source 52 . When the first belt 71 and the second belt 72 are driven until the sheet S is no longer detected in the area facing the external heat source 52, then the second belt 72 is stopped, and then the near-infrared heat source 52 is turned off. , or when the temperature of the near-infrared heat source 52 becomes equal to or lower than a predetermined temperature, the first belt 71 is stopped.

FIG. 7 is a front view schematically showing the internal configuration of the drying device 121 according to the second embodiment. Each of the first belt 71 and the second belt 72 is provided with a roller 42, a support plate 43, a suction unit 44, and a motor 45 similar to those in the first embodiment, and the first belt 71 and the second belt 72 rotate counterclockwise. driven by

FIG. 8 is a flow chart showing the procedure of transport control according to the second embodiment. The contents of the processing of the steps to which the step numbers common to those of the first embodiment (FIG. 5) are assigned are common to those of the first embodiment. In this flowchart, step S12 is added after step S11 in FIG. 5, and step S15a is provided instead of step S15 in FIG. At step S<b>12 , the control unit 30 stops driving the second belt 72 . After that, through step S13, the control unit 30 stops driving the first belt 71 (step S15a).

According to this configuration, it is possible to vary the manner of driving the first belt 71 and the second belt 72 depending on the situation. For example, the near-infrared heat source 52 is turned off, the first belt 71 and the second belt 72 are driven until the sheet S is no longer detected in the area facing the near-infrared heat source 52, and then the second belt 72 is stopped. After that, when a predetermined time has passed since the near-infrared heat source 52 was turned off, or when the temperature of the near-infrared heat source 52 becomes equal to or lower than a predetermined temperature, the first belt 71 is stopped. Therefore, when the sheet S enters the area facing the near-infrared heat source 52 after the sheet S is no longer detected, an excessive temperature rise of the sheet S can be prevented. Also, the electric power for driving the second belt 72 can be saved.

[First Modification of Second Embodiment]
Step S12 in the flow chart of FIG. 8 may be omitted. That is, when the jam of the sheet S is detected in the image forming system 100 and the sheet S is detected in the area facing the near-infrared heat source 52, the control unit 30 turns off the near-infrared heat source 52, When the first belt 71 and the second belt 72 are driven until the sheet S is no longer detected in the area facing the near-infrared heat source 52, and the near-infrared heat source 52 is turned off after a predetermined time has passed. , the first belt 71 is stopped. With this configuration as well, when the sheet S enters the area facing the near-infrared heat source 52 after the sheet S is no longer detected, an excessive temperature rise of the sheet S can be prevented.

Moreover, when step S12 is omitted, the first belt 71 and the second belt 72 may be stopped in step S15a. According to this configuration, power for driving the second belt 72 can be saved.

[Second Modification of Second Embodiment]
FIG. 9 is a front view schematically showing the internal configuration of a drying device 122 according to a second modified example of the second embodiment. In the drying device 122, the mid-infrared heat source 62 is provided upstream in the conveying direction Y from the near-infrared heat source 52, and the belt 41 includes a first belt 71 facing the near-infrared heat source 52 and a mid-infrared heat source and a second belt 72 opposite 62 , the transport unit 40 driving the first belt 71 at a faster speed than the second belt 72 . According to this configuration, compared to the case where the first belt 71 is driven at the same speed as the second belt 72, the amount of heat supplied from the near-infrared heat source 52 to the sheet S is reduced. Temperature rise can be suppressed.

100 Image forming system 120 Drying device 1 Printer (inkjet recording device)
6 image forming unit 7 transport unit (transport unit)
10 transport path 17 transport roller pair (transport unit)
18 registration roller pair (conveyor)
40 transport unit 41 belt 52 near-infrared heat source 62 mid-infrared heat source 71 first belt 72 second belt

Claims (15)

Equipped with an inkjet recording device and a drying device,
The inkjet recording device is
a conveying unit that conveys single sheets along a conveying path leading to the drying device;
an image forming unit that ejects ink onto the sheet conveyed by the conveying unit;
The drying device
a conveying unit including an endless belt that conveys the sheet conveyed from the inkjet recording apparatus;
a near-infrared heat source that radiates near-infrared rays to a portion of the conveying section in the conveying unit;
and a mid-infrared heat source that radiates mid-infrared rays to a section of the transport section that is upstream or downstream in the transport direction of the transport unit relative to the near-infrared heat source. 2. The image forming system according to claim 1, wherein the mid-infrared heat source is provided downstream of the near-infrared heat source in the conveying direction. The belt includes a first belt facing the near-infrared heat source and a second belt facing the mid-infrared heat source,
3. The image forming system according to claim 1, wherein the transport unit is capable of driving the first belt and the second belt individually. The mid-infrared heat source is provided upstream of the near-infrared heat source in the conveying direction,
The belt includes a first belt facing the near-infrared heat source and a second belt facing the mid-infrared heat source,
2. The image forming system according to claim 1, wherein the conveying unit drives the first belt at a faster speed than the second belt. 4. In the image forming system according to claim 2, when the sheet jam is detected and the sheet is detected in the area facing the near-infrared heat source, the area facing the near-infrared heat source and driving the belt until the sheet is no longer detected. When the sheet jam is detected in the image forming system and the sheet is detected in a region facing the near-infrared heat source, the near-infrared heat source is turned off and the near-infrared heat source is faced. When the belt is driven until the sheet is no longer detected in the area where the sheet is detected, and then a predetermined time has passed since the near-infrared heat source was turned off, or the temperature of the near-infrared heat source falls below a predetermined temperature. 6. The control method according to claim 5, wherein the belt is stopped when the belt becomes unbalanced. 4. In the image forming system according to claim 3, when the sheet jam is detected and the sheet is detected in a region facing the near-infrared heat source, the near-infrared heat source is turned off, and the near-infrared heat source is turned off. When the first belt and the second belt are driven until the sheet is no longer detected in the area facing the infrared heat source, and then a predetermined time has passed since the near-infrared heat source was turned off, or A control method, wherein the first belt is stopped when the temperature of the near-infrared heat source falls below a predetermined temperature. After driving the first belt and the second belt until the sheet is no longer detected in the area facing the near-infrared heat source, the second belt is stopped, and then the near-infrared heat source is turned off. 8. The control method according to claim 7, wherein the first belt is stopped when the predetermined period of time has elapsed since time or when the temperature of the near-infrared heat source has become equal to or lower than the predetermined temperature. . When the sheet jam is detected in the image forming system and the sheet is detected in a region facing the near-infrared heat source, the belt moves at a speed faster than before the sheet jam is detected. 9. The control method according to any one of claims 5 to 8, characterized in that the is driven. When the sheet jam is detected in the image forming system and the sheet is detected in a region facing the near-infrared heat source, the sheet is conveyed upstream of the conveying unit in the conveying direction. 10. The control method according to any one of claims 5 to 9, characterized by stopping. 11. The control method according to any one of claims 5 to 10, wherein only said mid-infrared heat source is turned on for said sheet on which only a monochrome image is printed. 12. The control method according to any one of claims 5 to 11, wherein said mid-infrared heat source and said near-infrared heat source are turned on for said sheet on which only a color image is printed. The mid-infrared heat source and the near-infrared heat source are turned on for the sheet on which the monochrome image and the color image are mixed, and the duty ratio of the near-infrared heat source is reduced more than in the case of only the color image. Control method according to any one of claims 5 to 12. 14. The control method according to any one of claims 5 to 13, wherein only the mid-infrared heat source is turned on when the sheet is plain paper or inkjet paper. 15. The control method according to any one of claims 5 to 14, wherein only the mid-infrared heat source is turned on when the ratio of the area occupied by ink dots to the area of the sheet is equal to or less than a threshold value. .

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