JP2021056341A - Image forming apparatus - Google Patents

Abstract

To provide an image forming apparatus that can prevent printing developer from being sublimated to an unintended portion on a medium due to sublimation transfer.SOLUTION: An image forming apparatus as an embodiment of the present invention comprises a first image forming unit, a second image forming unit, and a control unit. The first image forming unit develops a first image by using printing developer. The second image forming unit develops a second image by using a non-printing developer. The control unit, when laminating the second image on the first image on a medium, controls the amount of formation of the non-printing developer according to the amount of formation of the printing developer.SELECTED DRAWING: Figure 1

Description

The present invention relates to an image forming apparatus that forms an image using a printing and imaging agent.

In recent years, after forming an image on a medium using a printing imager, the image is sublimated and transferred onto another medium such as a cloth by iron transfer (see, for example, Patent Document 1).

JP-A-2019-28440

However, the print quality of the image formed by sublimation transfer is still insufficient, so there is room for improvement. The present invention has been made in view of such a problem, and an object of the present invention is to provide an image forming apparatus capable of suppressing sublimation of a printing imager to an unintended part on a medium by sublimation transfer. To do.

An image forming apparatus according to an embodiment of the present invention includes a first image forming unit, a second image forming unit, and a control unit. The first image forming unit visualizes the first image using a printing imaging agent. The second image forming unit visualizes the second image using a non-printing imager. The control unit controls the first image forming unit and the second image forming unit. The first image forming unit and the second image forming unit are arranged at positions where the first image and the second image can be laminated in this order on the medium discharged to the outside. The control unit is a second image forming unit so as to visualize the second image at a position where the first image is overlapped with the forming amount according to the forming amount of the printing imaging agent in the first image. To control.

According to the image forming apparatus as one embodiment of the present invention, it is possible to prevent the printing and imaging agent from sublimating to an unintended portion on the medium by sublimation transfer.

It is a figure which shows the schematic structure example of the image forming apparatus which concerns on one Embodiment of this invention. (A) It is a figure which shows the plane composition example of the printed toner image and the non-printed toner image formed on a medium. (B) It is a figure which shows the example of the cross-sectional structure in line AA of FIG. 2 (A). (A) It is a figure which shows the plane composition example of the printed toner image and the non-printed toner image formed on a medium. (B) It is a figure which shows the example of the cross-sectional structure in line AA of FIG. 3 (A). It is a figure which shows an example of the operation procedure of an image forming apparatus. (A) It is a figure which shows the state of iron transfer. (B) It is a figure which shows an example of the transfer image formed on the medium by iron transfer. (A) It is a figure which shows the state of iron transfer. (B) It is a figure which shows an example of the transfer image formed on the medium by iron transfer. It is a figure which shows the experimental result of the color difference when the printing black Duty is changed. It is a figure which shows the experimental result of the color difference when the printing yellow Duty is changed. It is a figure which shows the experimental result of the color difference when the printing magenta Duty is changed. It is a figure which shows the experimental result of the color difference when the printing cyan Duty is changed. It is a figure which shows the experimental result of the gamut difference when the printing yellow Duty is changed. It is a figure which shows the experimental result of the gamut difference when the printing magenta Duty is changed. It is a figure which shows the experimental result of the gamut difference when the printing cyan Duty is changed. It is a figure which shows an example of the relationship between the density duty of toner on a paper surface, and the adhesion amount (formation amount) of toner on a paper surface. It is a figure which shows one modification of the schematic structure of the image forming apparatus. (A) It is a figure which shows an example of the plane structure of the printed toner image and the non-printed toner image formed on the intermediate transfer belt. (B) It is a figure which shows the example of the cross-sectional structure in line AA of FIG. 16 (A). (A) It is a figure which shows the state of the secondary transcription. (B) It is a figure showing one of the plane configurations of the printed toner image and the non-printed toner image formed on the medium after the secondary transfer. (A) It is a figure which shows one modification of the planar composition of the printed toner image and the non-printed toner image formed on the intermediate transfer belt. (B) It is a figure which shows the example of the cross-sectional structure in line AA of FIG. 18 (A). (A) It is a figure which shows one modification of the planar composition of the printed toner image and the non-printed toner image formed on the intermediate transfer belt. (B) It is a figure which shows the example of the cross-sectional structure in line AA of FIG. 19 (A). It is a figure which shows an example of the operation procedure of an image forming apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description is a specific example of the present invention, and the present invention is not limited to the following aspects. Further, the present invention is not limited to the arrangement, dimensions, dimensional ratio, etc. of each component shown in each figure. The description will be given in the following order.

1. 1. Embodiment 2. Example 3. Modification example

<1. Embodiment>
[Constitution]
FIG. 1 shows an example of a schematic configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 is an apparatus for forming an image on the medium M1 using two types of toners (printing toner and non-printing toner), and is a so-called electrophotographic full-color printer. More specifically, the image forming apparatus 1 is a direct transfer type printer that directly forms an image with respect to the medium M1 to be discharged to the outside. The medium M1 is not particularly limited, but is, for example, a paper containing any one or more of a paper and a resin film.

For example, as shown in FIG. 1, the image forming apparatus 1 includes a medium supply unit 10, a conveying unit 20, an image forming unit 30, a transfer unit 40, and a fixing unit 50 inside the housing 1A. It includes a discharge unit 60 and a control unit 70. The housing 1A is provided with, for example, a storage unit 1S for storing the medium M1 on which the image is formed. In the image forming apparatus 1, the medium M1 is conveyed along the conveying path R indicated by the broken line.

The passage through which the medium M1 is conveyed is referred to as a transfer path R. In the transport path R, the direction toward the medium supply section 10 or a position closer to the medium supply section 10 when viewed from an arbitrary component is referred to as "upstream of the transport path R". In the transport path R, a direction opposite to the direction toward the medium supply section 10 or a position further away from the medium supply section 10 when viewed from an arbitrary component is referred to as "downstream of the transport path R". In the transport path R, the direction in which the medium M1 travels (that is, the direction from the upstream of the transport path R to the downstream of the transport path R) is referred to as the transport direction D.

(Structure of media supply unit 10)
The medium supply unit 10 supplies the media M1 one by one to the transport path R. The medium supply unit 10 has, for example, a medium supply tray 11 and a pickup roller 12. The medium supply tray 11 accommodates a plurality of media M1 in a stacked state. The medium supply tray 11 is detachably attached to the lower part of the image forming apparatus 1, for example. The pickup roller 12 supplies the medium M1 housed in the medium supply tray 11 to the transport unit 20. Under the control of the control unit 70, the pickup roller 12 rotates in the direction in which the medium M1 is fed out to the transport path R.

(Structure of transport unit 20)
The transport unit 20 transports the medium M1 from the medium supply unit 10 to the transfer unit 40 along the transport path R. The transport section 20 is arranged downstream of the transport path R from the medium supply section 10. The transport unit 20 has, for example, a pair of resist rollers 21 and 22.

The resist roller pair 21 is arranged upstream of the transfer path R from the resist roller pair 22, and specifically, is arranged between the medium supply tray 11 and the resist roller pair 22. The resist roller pair 21 abuts the medium M1 to be conveyed along the transfer path R, and then conveys the medium M1 in the transfer direction D along the transfer path R. The abutting process refers to abutting the tip of the medium M1 conveyed from the medium supply unit 10 against the resist roller pair 21 whose rotation has been stopped. While the abutting process is being performed, the power of the motor controlled by the control unit 70 is not transmitted to the resist roller pair 21. That is, the resist roller pair 21 stops rotating while the abutting process is being performed. Further, when the medium M1 is conveyed, the resist roller pair 21 is controlled by the control unit 70 and rotates in the direction in which the medium M1 is conveyed in the conveying direction D.

The resist roller pair 22 is arranged downstream of the transfer path R from the resist roller pair 21. The resist roller pair 22 transports the medium M1 transported along the transport path R in the transport direction D along the transport path R. The resist roller pair 22 rotates in the direction in which the medium M1 is conveyed in the transfer direction D under the control of the control unit 70.

(Structure of image forming unit 30)
The image forming unit 30 is arranged downstream of the transport path R from the transport unit 20. The image forming unit 30 performs a developing process using toner. Specifically, the image forming unit 30 forms an electrostatic latent image and uses Coulomb force to attach toner to the electrostatic latent image.

The image forming unit 30 has, for example, five developing units 30Y, 30M, 30C, 30K, and 30N that perform development processing. Each of the developing units 30Y, 30M, 30C, 30K, and 30N has the same configuration as each other, except that, for example, the types (colors) of the toners mounted on the developing units are different from each other. Each of the developing units 30Y, 30M, 30C, 30K, and 30N has, for example, a photoconductor drum 31 on which an electrostatic latent image is formed and a light source 32 on which an electrostatic latent image is formed on the surface of the photoconductor drum 31. doing. Each of the developing units 30Y, 30M, 30C, 30K, and 30N further includes, for example, a charging roller, a developing roller, a supply roller, and the like.

The photoconductor drum 31 has a peripheral surface including a photoconductor (for example, an organic photoconductor), and is a columnar member capable of supporting an electrostatic latent image on the peripheral surface. Specifically, the photoconductor drum 31 has a conductive support and a photoconducting layer that covers the outer periphery (surface) thereof. The conductive support is made of, for example, a metal pipe made of aluminum. The photoconducting layer has, for example, a structure in which a charge generation layer and a charge transport layer are laminated in this order. Under the control of the control unit 70, the photoconductor drum 31 rotates at a predetermined peripheral speed in the direction in which the medium M1 is conveyed in the transfer direction D.

The light source 32 is an exposure device that forms an electrostatic latent image on the peripheral surface of the photoconductor drum 31 by exposing the charged peripheral surface of the photoconductor drum 31. The light source 32 has, for example, a plurality of light emitting units arranged in the width direction of the photoconductor drum 31. Each light emitting unit includes, for example, a light source such as a light emitting diode (LED) that emits irradiation light, and a lens array that forms an image of the irradiation light on the surface of the photoconductor drum 31.

The developing units 30Y, 30M, 30C, 30K, and 30N are arranged in this order from upstream to downstream in the transport direction D of the medium M1, for example. That is, the developing unit 30N is arranged downstream of the developing units 30Y, 30M, 30C, and 30K in the transport direction D of the medium M1 by the transport unit 20. That is, the developing units 30Y, 30M, 30C, 30K, and 30N have a printed toner image NTI (first image) (see, for example, FIG. 2 described later) and a non-printed toner image CTI on the medium M1 discharged to the outside. (Second image) is arranged at a position where it is possible to stack in this order. The developing unit including the developing units 30Y, 30M, 30C, and 30K corresponds to a specific example of the "first image forming unit" of the present invention. The developing unit 31N corresponds to a specific example of the "second image forming unit" of the present invention.

The developing unit 30Y forms a printing toner image using, for example, a printing yellow toner. The developing unit 30M forms a printing toner image using, for example, a printing magenta toner. The developing unit 30C forms a printing toner image using, for example, a printing cyan toner. The developing unit 30K forms a printing toner image using, for example, printing black toner. The developing unit including the developing units 30Y, 30M, 30C, and 30K forms a printing toner image using printing toner (printing yellow toner, printing magenta toner, printing cyan toner, and printing black toner). The printing toner image is formed by printing toner (printing yellow toner, printing magenta toner, printing cyan toner, and printing black toner). The developing unit including the developing units 30Y, 30M, 30C, and 30K transfers the printing toner formed by each of the developing units 30Y, 30M, 30C, and 30K onto the medium M1 to directly transfer the printing toner onto the medium M1. The image NTI (first image) is formed. The developing unit including the developing units 30Y, 30M, 30C, and 30K forms, for example, a printing toner image (image) corresponding to image data input from the outside as a printing toner image NTI (first image). Here, the image data is image data input to the control unit 70 from the outside. The developing unit including the developing units 30Y, 30M, 30C, and 30K has a printing toner image (image) corresponding to the image data input from the outside by inputting a print control signal corresponding to the image data from the control unit 70. To form.

On the other hand, the developing unit 30N forms a non-printing toner image using, for example, a non-printing toner. The non-printed toner image is formed by the non-printed toner. The developing unit 30N directly forms the non-printing toner image CTI (second image) on the medium M1 by transferring the non-printing toner formed by the developing unit 30N onto the medium M. The developing unit 30N forms a non-printing toner image CTI (second image) so as to be in contact with the first image on the medium M by transferring the non-printing toner formed by the developing unit 30N onto the medium M. To do. The developing unit 30N forms, for example, a non-printing toner image (image) capable of covering the printing toner image NTI (first image) on the medium M1 as a non-printing toner image CTI (second image). .. For example, when the unprinted toner image CTI is laminated on the printing toner image NTI on the medium M1, the developing unit 30N controls the printing toner image NTI by controlling the control unit 70 to form the unprinted toner image NTI in an amount corresponding to the forming amount of the non-printing toner image NTI. Image CTI is formed.

Each of the printing yellow toner, printing magenta toner, printing cyan toner, and printing black toner is a toner used to form a full-color image, and in particular, it is transferred to the medium M2 described later by utilizing sublimation transferability at the time of heating. It is a possible colored toner. The medium M2 is a medium different from the medium M1 on which an image is formed by using the image forming apparatus 1, and is, for example, a cloth. On the other hand, the non-printing toner is, for example, a toner used to improve the print quality of an image transferred to the medium M2 when the image formed on the medium M1 is transferred to the medium M2.

The printing toner is a toner containing a printing imager. The printing imaging agent contained in the printing toner is a colorant having a relatively sublimable property as compared with the non-printing toner. Therefore, in the present specification, the description of "forming a printing toner image" may be read as "visualizing a printing toner image" as appropriate. On the other hand, the non-printing toner is a toner that does not contain a printing imager, and is made of a material having a relatively low sublimation property as compared with the colorant contained in the printing toner. The non-printing toner is, for example, a clear toner. Therefore, in the present specification, the description of "forming a non-printed toner image" may be read as "visualizing a non-printed toner image" as appropriate. The detailed configurations of the printing toner (printing magenta toner, printing cyan toner, and printing black toner) and the non-printing toner will be described later.

(Structure of transfer unit 40)
The transfer unit 40 performs a transfer process using the toner developed by the image forming unit 30. Specifically, the transfer unit 40 transfers the toner adhering to the electrostatic latent image of the photoconductor drum 31 to the medium M1 conveyed from the transfer unit 20.

The transfer unit 40 has, for example, five transfer rollers 40Y, 40M, 40C, 40K, 40N. The transfer rollers 40Y, 40M, 40C, 40K, and 40N transfer (directly transfer) the toner attached to the electrostatic latent image to the medium M1. The transfer roller 40Y is pressed against the photoconductor drum 31 of the developing unit 30Y. The transfer roller 40M is pressed against the photoconductor drum 31 of the developing unit 30M. The transfer roller 40C is pressed against the photoconductor drum 31 of the developing unit 30C. The transfer roller 40K is pressed against the photoconductor drum 31 of the developing unit 30K. The transfer roller 40N is pressed against the photoconductor drum 31 of the developing unit 30N. The transfer rollers 40Y, 40M, 40C, 40K, and 40N rotate in the direction in which the medium M1 is conveyed in the transfer direction D under the control of the control unit 70.

(Structure of fixing portion 50)
The fixing unit 50 performs a fixing process using the toner transferred to the medium M1 by the transfer unit 40. Specifically, the fixing unit 50 fixes the toner to the medium M1 by pressurizing the medium M1 to which the toner is transferred by the transfer unit 40 while heating. The fixing portion 50 includes, for example, an upper roller 51 and a lower roller 52.

The upper roller 51 and the lower roller 52 are configured to include, for example, a heat source that is a heating heater such as a halogen lamp inside, and function as a heating roller that applies heat to the toner on the medium M1. Under the control of the control unit 70, the upper roller 51 rotates in the direction in which the medium M1 is conveyed in the transfer direction D. The heat source in the upper roller 51 and the lower roller 52 receives the supply of the bias voltage controlled by the control unit 70, and controls the surface temperatures of the upper roller 51 and the lower roller 52. The lower roller 52 is arranged to face the upper roller 51 so that a pressure contact portion is formed between the lower roller 52 and the upper roller 51, and functions as a pressure roller that applies pressure to the toner on the medium M1. .. The lower roller 52 may have a surface layer made of an elastic material.

(Structure of discharge unit 60)
The discharge unit 60 discharges the medium M1 to which the toner is fixed by the fixing unit 50 to the outside. The discharge unit 60 has, for example, a transport roller pair 61, 62, 63. The transport roller pairs 61, 62, 63 discharge the medium M1 to the outside via the transport path R and store the medium M1 in the external storage unit 1S. The transfer roller pairs 61, 62, and 63 rotate in the direction in which the medium M1 is conveyed in the transfer direction D under the control of the control unit 70. The transport roller pairs 61, 62, 63 further discharge the medium M1 to the storage unit 1S face-down, for example.

(Structure of control unit 70)
The control unit 70 controls the overall operation of the image forming apparatus 1. The control unit 70 is, for example, a circuit board including a control circuit, a memory, an input / output port, a timer, and the like, and the control circuit includes, for example, a central processing unit (CPU) and the like.

The control unit 70 forms the image corresponding to the image data (first image data) input from the outside as the printing toner image NTI (first image), so that the developing units 30Y, 30M, 30C, 30K Controls a development unit consisting of. The control unit 70, for example, sends print control signals for forming a printing toner image NTI (first image) corresponding to image data (first image data) input from the outside to the developing units 30Y, 30M. Output to a development unit consisting of 30C and 30K. The control unit 70 further forms a non-printing toner image CTI (second image) on the medium M1 so as to form an image capable of covering the printing toner image NTI (first image). To control. The control unit 70 transmits, for example, a print control signal for forming a non-printed toner image CTI (second image) capable of covering the printed toner image NTI (first image) on the medium M1. Output to 30N. For example, when the non-printed toner image CTI is laminated on the printing toner image NTI on the medium M1, the control unit 70 controls the amount of the non-printed toner image CTI formed according to the amount of the printed toner image NTI formed.

(Structure of Printed Toner Image NTI and Non-Printed Toner Image CTI)
FIG. 2 shows an example of the printed toner image NTI and the non-printed toner image CTI formed on the medium M1. FIG. 2A shows a plan configuration example of the printed toner image NTI and the non-printed toner image CTI formed on the medium M1. FIG. 2B shows an example of a cross-sectional configuration taken along the line AA of FIG. 2A. In FIGS. 2 (A) and 2 (B), the first region in ^{which the printing toner image NTI has a relatively large amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI. It is composed of NTIa and a second region NTIb in which the ^{amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI is relatively small. In FIGS. 2A and 2B, the amount of formation (mg / cm ² ) of the first region NTIa and the second region NTIb is a value such that the concentration duty described later is equal to or less than a predetermined threshold value. There is.

^{The amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI has a predetermined correlation (for example, roughly proportional) with the density duty of the printing toner (printing imager) in the printing toner image NTI. Relationship). The density duty corresponds to the printed image density.

Here, when performing solid printing on the entire surface in a printable range of a predetermined area (for example, one round of a photosensitive drum or one page of a printing medium), the density duty when printing at an area ratio of 100% is set to 100% density duty. The printing corresponding to the area of 1% with respect to the density duty of 100% is called the density duty of 1%.

Concentration duty = [Cm (i) / (Cd × C0)] × 100
Cm (i): The number of dots actually used in printing when the photoconductor drum rotates Cd, that is, the number of exposed dots C0: The number of dots per rotation of the photoconductor drum, that is, the presence or absence of exposure. Not limited to dots that are possible (potentially dots in printing) per rotation of the photoconductor drum. For example, the number of dots used in the case of a solid image (solid image) Cd × C0: The number of dots that can be (potentially dots in printing) when the photoconductor drum is rotated by Cd.

The printing toner image NTI is formed on the medium M1 and in the print region α of the medium M1. The non-printing toner image CTI is formed on the medium M1 so as to cover the printing toner image NTI formed on the medium M1. The non-printing toner image CTI is formed, for example, in contact with the surface of the printing toner image NTI. The unprinted toner image CTI may be formed on the medium M1 and may be formed on the entire print region α, for example. At this time, the developing unit 30N forms, for example, the unprinted toner image CTI on the medium M1 and over the entire printing area α.

In the developing unit 30N, for example, the non-printing toner image CTI is ^{formed in an amount of 0.16 mg / cm 2} or more, and the printing image agent is not removed from the printing toner image NTI at the time of iron transfer described later. The printing toner image is formed in an amount within a range that can be transferred to the medium M2 via the CTI. The developing unit 30N forms a non-printing toner image CTI at a position where it is laminated with the printing toner image NTI, for example, at an amount formed according to the amount of the printing toner (printing imager) formed in the printing toner image NTI. The control unit 70 calculates the density duty of the printing toner (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. When the calculated density duty is equal to or less than a predetermined threshold value, the control unit 70 controls the developing unit 30N so as to form an image covering the printed toner image NTI formed on the medium M1 as a non-printed toner image CTI. .. When the calculated density duty is equal to or less than a predetermined threshold value, the control unit 70 performs a non-printing toner image CTI at a position where it is laminated with a portion of the printed toner image NTI on the medium M1 whose calculated density duty is equal to or less than a predetermined threshold value. The developing unit 30N is controlled so as to form.

When the density duty of the printing toner (printing imager) in the printing toner image NTI is 60% or less or 40% or less, the developing unit 30N is, for example, the printing toner (printing imager) used in the printing toner image NTI. A non-printed toner image CTI is formed on the medium M1 and so as to cover the printed toner image NTI formed on the medium M1 regardless of the image developer. At this time, when the calculated density duty is 60% or less or 40% or less, the control unit 70 forms an image covering the printed toner image NTI formed on the medium M1 as the non-printed toner image CTI. The developing unit 30N is controlled. When the calculated density duty is 60% or less or 40% or less, the control unit 70 is positioned to be laminated with the portion of the printed toner image NTI on the medium M1 where the calculated density duty is 60% or less or 40% or less. The developing unit 30N is controlled so as to form a non-printed toner image CTI.

When the printing toner image NTI is formed of printing black and the density duty of printing black (printing imager) is 80% or less, the developing unit 30N is formed on, for example, the medium M1 and on the medium M1. A non-printing toner image CTI is formed so as to cover the printed toner image NTI. The developing unit 30N forms, for example, a non-printing toner image CTI at a position where the printing toner image NTI on the medium M1 is laminated with a portion where the density duty of the printing black (printing imager) is 80% or less. At this time, the control unit 70 calculates the density duty of the printing black (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. When the calculated density duty of the printing black (printing imaging agent) is 80% or less, the control unit 70 forms an image covering the printing toner image NTI formed on the medium M1 as a non-printing toner image CTI. In addition, the developing unit 30N is controlled. When the calculated density duty of the printing black (printing imager) is 80% or less, the control unit 70 determines that the calculated density duty of the printing black (printing imager) in the printing toner image NTI on the medium M1 is 80% or less. The developing unit 30N is controlled so as to form an unprinted toner image CTI at a position where it is laminated with a portion having 80% or less.

When the printing toner image NTI is formed of printing yellow and the density duty of printing yellow (printing imager) is 70% or less or 60% or less, the developing unit 30N is, for example, on the medium M1 and the medium M1. A non-printed toner image CTI is formed so as to cover the printed toner image NTI formed above. The developing unit 30N is, for example, a non-printing toner image CTI at a position where it is laminated with a portion of the printing toner image NTI on the medium M1 where the density duty of the printing yellow (printing imager) is 70% or less or 60% or less. To form. At this time, the control unit 70 calculates the density duty of the printing yellow (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. When the calculated density duty of the printing yellow (printing imaging agent) is 70% or less or 60% or less, the control unit 70 uses the printing toner image CTI as an image covering the printing toner image NTI formed on the medium M1. The developing unit 30N is controlled so as to form. When the density duty of the calculated printing yellow (printing imaging agent) is 70% or less or 60% or less, the control unit 70 has calculated the printing yellow (printing imaging agent) in the printing toner image NTI on the medium M1. The developing unit 30N is controlled so as to form an unprinted toner image CTI at a position where it is laminated with a portion having a density duty of 70% or less or 60% or less.

Further, when the printing toner image NTI is formed of the printing magenta and the density duty of the printing magenta (printing imager) is 80% or less or 70% or less, the developing unit 30N is, for example, on the medium M1 and A non-printed toner image CTI is formed so as to cover the printed toner image NTI formed on the medium M1. The developing unit 30N is, for example, a non-printing toner image CTI at a position where it is laminated with a portion of the printing toner image NTI on the medium M1 where the density duty of the printing magenta (printing magenta) is 80% or less or 70% or less. To form. At this time, the control unit 70 calculates the density duty of the printing magenta (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. When the calculated density duty of the printing magenta (printing image processing agent) is 80% or less or 70% or less, the control unit 70 serves as a non-printing toner image CTI, an image covering the printing toner image NTI formed on the medium M1. The developing unit 30N is controlled so as to form. When the density duty of the calculated printing magenta (printing and imaging agent) is 80% or less or 70% or less, the control unit 70 has calculated the printing magenta (printing and imaging agent) in the printing toner image NTI on the medium M1. The developing unit 30N is controlled so as to form an unprinted toner image CTI at a position where it is laminated with a portion having a density duty of 80% or less or 70% or less.

Further, when the printing toner image NTI is formed of printing cyan and the density duty of printing cyan (printing imager) is 60% or less or 40% or less, the developing unit 30N is, for example, on the medium M1 and A non-printed toner image CTI is formed so as to cover the printed toner image NTI formed on the medium M1. The developing unit 30N is, for example, a non-printing toner image CTI at a position where it is laminated with a portion of the printing toner image NTI on the medium M1 where the density duty of the printing cyan (printing imager) is 60% or less or 40% or less. To form. At this time, the control unit 70 calculates the density duty of the printing cyan (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. When the calculated density duty of the printing cyan (printing image processor) is 60% or less or 40% or less, the control unit 70 serves as a non-printing toner image CTI and covers an image of the printing toner image NTI formed on the medium M1. The developing unit 30N is controlled so as to form. When the density duty of the calculated printing cyan (printing and imaging agent) is 60% or less or 40% or less, the control unit 70 has calculated the printing cyan (printing and imaging agent) in the printing toner image NTI on the medium M1. The developing unit 30N is controlled so as to form an unprinted toner image CTI at a position where it is laminated with a portion having a density duty of 60% or less or 40% or less.

FIG. 3 shows an example of the printed toner image NTI and the non-printed toner image CTI formed on the medium M1. FIG. 3A shows a plan configuration example of the printed toner image NTI and the non-printed toner image CTI formed on the medium M1. FIG. 3B shows an example of a cross-sectional configuration taken along the line AA of FIG. 3A. In FIGS. 3 (A) and 3 (B), the first region in ^{which the printing toner image NTI has a relatively large amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI. It is composed of NTIa and a second region NTIb in which the ^{amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI is relatively small. In FIGS. 3A and 3B, the amount of formation of the first region NTIa (mg / cm ² ) has a value such that the concentration duty becomes larger than a predetermined threshold value, and the second region NTIb The amount of formation (mg / cm ² ) is such that the concentration duty becomes smaller than a predetermined threshold value.

The printing toner image NTI is formed on the medium M1 and in the print region α of the medium M1. The non-printing toner image CTI is formed on the medium M1 so as to cover the second region NTIb of the printing toner image NTI formed on the medium M1. At this time, the non-printing toner image CTI is on the medium M1 and is not in contact with the first region NTIa of the printing toner image NTI formed on the medium M1 and does not cover the first region NTIa. .. The non-printing toner image CTI is formed, for example, in contact with the surface of the second region NTIb of the printing toner image NTI. At this time, the developing unit 30N forms, for example, the unprinted toner image CTI on the medium M1 and in the printing area α excluding the first area NTIa.

When the density duty of the first region NTIa is larger than the predetermined threshold value and the density duty of the second region NTIb is smaller than the predetermined threshold value, the control unit 70 is laminated with the first region NTIa of the printing toner image NTI. The developing unit 30N is controlled so as not to form an unprinted toner image CTI at the position. The control unit 70 controls the developing unit 30N so that the unprinted toner image CTI is not formed at a position where the calculated density duty is overlapped with a portion larger than a predetermined threshold value.

When the density duty of the printing toner (printing imager) in the printing toner image NTI is larger than 60% or larger than 40%, the developing unit 30N is, for example, the printing toner (printing toner) used for the printing toner image NTI. A non-printing toner image CTI is formed on the medium M1 so as not to cover the printing toner image NTI formed on the medium M1 regardless of the imaging agent of the imaging agent). The developing unit 30N is, for example, a non-printing toner image CTI at a position where the density duty of the printing toner image NTI is greater than 60% or greater than 40% of the printing toner image NTI on the medium M1. Does not form. At this time, when the calculated density duty is larger than 60% or larger than 40%, the control unit 70 is positioned to be laminated with the printed toner image NTI formed on the medium M1 as the non-printed toner image CTI. The developing unit 30N is controlled so as to form an image that does not cover the image. When the density duty of the calculated printing toner image NTI is larger than 60% or larger than 40%, the control unit 70 has the density duty of the calculated printing toner image NTI among the printed toner image NTI on the medium M1. The developing unit 30N is controlled so that the unprinted toner image CTI is not formed at a position where the amount is larger than 60% or overlapped with the portion larger than 40%.

The printing toner image NTI is formed of printing black, the density duty of printing black (printing imager) in the first region NTIa is larger than 80%, and the density duty of printing black (printing imager) in the second region NTIb. When is 80% or less, the developing unit 30N does not cover, for example, the position of the printing toner image NTI formed on the medium M1 and overlapping with the first region NTIa. A printing toner image CTI is formed. That is, the developing unit 30N does not form the unprinted toner image CTI at the position where it is laminated with the first region NTIa. At this time, the control unit 70 calculates the density duty of the printing black (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. In the control unit 70, the calculated density duty of the printing black (printing imager) in the first region NTIa is larger than 80%, and the calculated density duty of the printing black (printing imager) in the second region NTIb is 80. In the case of% or less, the developing unit 30N is controlled as the non-printing toner image CTI so as to form an image of the printing toner image NTI formed on the medium M1 that does not cover the position where it is laminated with the first region NTIa. .. That is, the control unit 70 controls the developing unit 30N so as not to form the unprinted toner image CTI at the position where it is laminated with the first region NTIa.

The printing toner image NTI is formed of printing yellow, and the density duty of the printing yellow (printing imager) in the first region NTIa is larger than 70% or more than 60%, and the printing yellow in the second region NTIb (printing yellow). When the density duty of the printing / imaging agent) is 70% or less, or 60% or less, the developing unit 30N is, for example, among the printing toner image NTI formed on the medium M1 and on the medium M1. An unprinted toner image CTI is formed so as not to cover the position where it is laminated with the first region NTIa. That is, the developing unit 30N does not form the unprinted toner image CTI at the position where it is laminated with the first region NTIa. At this time, the control unit 70 calculates the density duty of the printing yellow (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. The control unit 70 has calculated that the density duty of the printing yellow (printing imager) in the first region NTIa is larger than 70% or more than 60%, and the calculated printing yellow (printing manifestation) in the second region NTIb is calculated. When the density duty of the image agent) is 70% or less or 60% or less, the non-printing toner image CTI covers the position of the printed toner image NTI formed on the medium M1 to be laminated with the first region NTIa. The developing unit 30N is controlled so as to form a non-existent image. That is, the control unit 70 controls the developing unit 30N so as not to form the unprinted toner image CTI at the position where it is laminated with the first region NTIa.

Further, the printing toner image NTI is formed by the printing magenta, and the density duty of the printing magenta (printing imager) in the first region NTIa is larger than 80% or more than 70%, and the printing in the second region NTIb. When the density duty of magenta (printing imager) is 80% or less, or 70% or less, the developing unit 30N is, for example, on the medium M1 and the printing toner image NTI formed on the medium M1. Of these, the unprinted toner image CTI is formed so as not to cover the position where it is laminated with the first region NTIa. That is, the developing unit 30N does not form the unprinted toner image CTI at the position where it is laminated with the first region NTIa. At this time, the control unit 70 calculates the density duty of the printing magenta (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. The control unit 70 has calculated that the density duty of the printing magenta (printing imager) in the first region NTIa is larger than 80% or larger than 70%, and the calculated printing magenta (printing magenta) in the second region NTIb is calculated. When the density duty of the image agent) is 80% or less or 70% or less, the non-printing toner image CTI covers the position of the printed toner image NTI formed on the medium M1 to be laminated with the first region NTIa. The developing unit 30N is controlled so as to form a non-existent image. That is, the control unit 70 controls the developing unit 30N so as not to form the unprinted toner image CTI at the position where it is laminated with the first region NTIa.

Further, the printing toner image NTI is formed of printing cyan, and the density duty of printing cyan (printing imager) in the first region NTIa is larger than 60% or more than 40%, and printing in the second region NTIb. When the concentration duty of cyan (printing imager) is 60% or less, or 40% or less, the developing unit 30N is, for example, on the medium M1 and the printing toner image NTI formed on the medium M1. Of these, the unprinted toner image CTI is formed so as not to cover the position where it is laminated with the first region NTIa. That is, the developing unit 30N does not form the unprinted toner image CTI at the position where it is laminated with the first region NTIa. At this time, the control unit 70 calculates the density duty of the printing cyan (printing imager) in the printing toner image NTI based on the image data (first image data) input from the outside. The control unit 70 has calculated that the density duty of the printing cyan (printing image processor) in the first region NTIa is larger than 60% or larger than 40%, and the calculated printing cyan (printing manifestation) in the second region NTIb is calculated. When the density duty of the image agent) is 60% or less or 40% or less, the non-printing toner image CTI covers the position of the printed toner image NTI formed on the medium M1 to be laminated with the first region NTIa. The developing unit 30N is controlled so as to form a non-existent image. That is, the control unit 70 controls the developing unit 30N so as not to form the unprinted toner image CTI at the position where it is laminated with the first region NTIa.

(Toner composition)
The toner described here is, for example, a negatively charged toner of a one-component developing method. That is, the toner has, for example, a negative charging polarity. The one-component developing method is a method in which an appropriate amount of electric charge is applied to the toner itself without using a carrier (magnetic particles) for applying an electric charge to the toner. On the other hand, the two-component developing method is a method in which the above-mentioned carrier and toner are mixed and an appropriate amount of charge is applied to the toner by utilizing the friction between the carrier and the toner.

The method for producing the toner is not particularly limited. Specifically, the method for producing the toner may be, for example, a pulverization method, a polymerization method, or a method other than these. Of course, two or more of the above-mentioned production methods may be used in combination. The polymerization method is, for example, an emulsion polymerization agglutination method and a dissolution suspension method.

(Composition of non-printing toner)
The non-printing toner is a toner to be dyed that has a property of being dyed by a printing imaging agent (coloring agent) contained in the printing toner. That is, as will be described later, the non-printing toner is a receptor that receives the printing image agent that is transferred from the printing toner by using the heat energy when the printing toner is supplied with heat energy. .. When this non-printing toner receives the printing imaging agent, the non-printing toner is dyed by the printing imaging agent.

This non-printing toner is a imaging agent to be dyed, which contains a polymer compound that can be dyed by the printing imaging agent (coloring agent) contained in the printing toner. This non-printing toner contains, for example, any one or more of the polymer compounds. This polymer compound is a polymer compound having a property of being dyed by a printing imager. Specifically, the polymer compound is, for example, a polyester resin, a styrene-acrylic resin, an epoxy resin, a styrene-butadiene resin, or the like.

Polyester-based resin is a general term including polyester and its derivatives. That is, the "system" in the "polyester-based resin" means that not only the polyester but also the derivative is included. The definition of "system" is the same for styrene-acrylic resin, epoxy resin, styrene-butadiene resin and the like.

Above all, the polymer compound preferably contains a polyester resin. First, the non-printing toner is easily dyed by the printing imager. Secondly, since the polyester-based resin has a high affinity for the medium M1 such as paper, the non-printing toner containing the polyester-based resin is easily fixed to the medium M1. Thirdly, since the polyester-based resin has high physical strength even when the molecular weight is relatively small, the non-printing toner containing the polyester-based resin has excellent durability. Fourth, even if the non-printing toner has essentially low charging characteristics, the non-printing toner is likely to be fixed to the medium M1.

The crystalline state of the polyester resin is not particularly limited. Therefore, the polyester-based resin may be crystalline polyester, amorphous polyester, or both. Of these, crystalline polyester is preferable. This is because the non-printing toner is easily dyed by the printing imager. Further, the non-printing toner is easily fixed by the medium M1, and the durability of the non-printing toner is further improved.

This polyester resin is, for example, a reaction product (condensate polymer) of one or more alcohols and one or two carboxylic acids.

The type of alcohol is not particularly limited, but among them, a divalent or higher alcohol and a derivative thereof are preferable. The divalent or higher alcohols include, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, cyclohexanedimethanol, xylene glycol, dipropylene glycol, polypropylene glycol, and bisphenol A. , Hydrated bisphenol A, bisphenol A ethylene oxide, bisphenol A propylene oxide, sorbitol and glycerin.

The type of carboxylic acid is not particularly limited, but among them, a divalent or higher carboxylic acid and a derivative thereof are preferable. The divalent or higher carboxylic acids include, for example, maleic acid, fumaric acid, phthalic acid, isophthalic acid, terephthalic acid, succinic acid, adipic acid, trimellitic acid, pyromellitic acid, cyclopentanedicarboxylic acid, succinic anhydride, and anhydrous. Trimellitic acid, maleic anhydride and dodecenyl succinic anhydride and the like.

The color of the non-printing toner is not particularly limited. Therefore, the non-printing toner may contain a colorant like the printing toner, and unlike the printing toner, the non-printing toner may not contain a colorant. This colorant does not have dyeability, unlike the colorant (printing imager) contained in the printing toner.

When the non-printing toner does not contain a colorant, the color of the non-printing toner is colorless (transparent). This colorless non-printing toner is, for example, a so-called clear toner. In this case, since the color of the non-printing toner image CTI becomes colorless, the hue of the non-printing toner image CTI has almost no effect on the hue of the printing toner image NTI.

When the non-printing toner contains a colorant having no dyeability, the color of the non-printing toner is not particularly limited. Therefore, the color of the non-printing toner may be yellow, magenta, cyan, black, white, or a mixture of two or more of them. In this case, the non-printing toner contains, for example, a colorant having a color corresponding to the color of the non-printing toner, and the colorant is, for example, one or more of pigments and dyes. Includes. As an example, white non-printing toner contains pigments such as titanium oxide.

Among them, the color of the non-printing toner is preferably white because the hue of the non-printing toner image CTI is preferably a color that does not easily affect the hue of the printing toner image NTI. However, the color of the non-printing toner is not limited to white and may be a light color such as light gray as long as the hue of the non-printing toner image CTI does not easily affect the hue of the printing toner image NTI.

Here, as described above, the color of the non-printing toner is preferably a color in which the hue of the non-printing toner image CTI does not easily affect the hue of the printing toner image NTI. Therefore, the color of the non-printing toner is more preferably colorless (transparent) and white, and further preferably colorless. That is, since the non-printing toner does not contain a colorant, it is particularly preferable that the color of the non-printing toner is colorless.

However, the non-printing toner may further contain any one or more of other materials such as additives. The types of other materials are not particularly limited, but are, for example, external additives, mold release agents, charge control agents, conductive modifiers, reinforcing fillers, antioxidants, antioxidants, fluidity improvers and cleanability. Such as an improver.

The external additive mainly improves the fluidity of the toner by suppressing agglutination of the toner and the like. This external additive contains, for example, any one or more of inorganic materials and organic materials. The inorganic material is, for example, hydrophobic silica. The organic material is, for example, a melamine resin.

The content of the external additive is not particularly limited, but is, for example, 0.01 parts by weight to 10 parts by weight, preferably 0.05 parts by weight to 8 parts by weight with respect to 100 parts by weight of the polymer compound.

The release agent mainly improves the fixability and offset resistance of the toner. This mold release agent is, for example, any one or two of waxes such as aliphatic hydrocarbon wax, oxide of aliphatic hydrocarbon wax, fatty acid ester wax, and deoxidation of fatty acid ester wax. Includes more than one type. In addition, the release agent may be, for example, a block copolymer of the series of waxes described above.

Aliphatic hydrocarbon waxes include, for example, low molecular weight polyethylenes, low molecular weight polypropylenes, olefin copolymers, microcrystalline waxes, paraffin waxes and Fishertropsh waxes. The oxide of the aliphatic hydrocarbon wax is, for example, polyethylene oxide wax. The fatty acid ester wax is, for example, carnauba wax and montanic acid ester wax. The deoxidized fatty acid ester wax is a wax obtained by deoxidizing a part or all of the fatty acid ester wax, for example, deoxidized carnauba wax.

The content of the release agent is not particularly limited, but is, for example, 0.1 parts by weight to 20 parts by weight, preferably 0.5 parts by weight to 12 parts by weight with respect to 100 parts by weight of the polymer compound.

The charge control agent mainly controls the triboelectric chargeability of the toner. The charge control agent used for the negatively charged toner contains, for example, any one or more of azo-based complexes, salicylic acid-based complexes, calixarene-based complexes, and the like.

The content of the charge control agent is not particularly limited, but is, for example, 0.05 parts by weight to 15 parts by weight with respect to 100 parts by weight of the polymer compound.

(Composition of printing toner)
Each of the printing yellow toner, the printing magenta toner, the printing cyan toner, and the printing black toner contains a printing imager of a color corresponding to each color. The printing imager is a printing yellow dye, a printing magenta dye, a printing cyan dye, and a printing black dye.

Specifically, the printing yellow toner contains, for example, any one or more of the printing yellow dyes as a colorant, and any one of the binders instead of the polymer compound. It has the same configuration as non-printing toner, except that it contains one type or two or more types. The printing yellow dye is, for example, C.I. LReactiveYello2, C.I. LDisperseYellow54, DisperseYellow160 and C.I. LYellow114 and the like. The binder is, for example, a polyester resin, a styrene-acrylic resin, an epoxy resin, a styrene-butadiene resin, or the like.

However, unlike the non-printing toner, the printing yellow toner does not have to contain a release agent. In this case, mainly due to the presence or absence of the release agent, the printed toner and the non-printed toner have different thermal physical properties (endothermic characteristics). This difference in endothermic characteristics will be described later.

The content of the printing yellow dye is not particularly limited, but is, for example, 2 parts by weight to 25 parts by weight, preferably 2 parts by weight to 15 parts by weight with respect to 100 parts by weight of the binder. The content of the release agent is not particularly limited, but is, for example, 0.1 parts by weight to 20 parts by weight, preferably 0.5 parts by weight to 12 parts by weight with respect to 100 parts by weight of the binder. The charge control agent is not particularly limited, but is, for example, 0.05 parts by weight to 15 parts by weight with respect to 100 parts by weight of the binder. The content of the external additive is not particularly limited, but is, for example, 0.01 parts by weight to 10 parts by weight, preferably 0.05 parts by weight to 8 parts by weight with respect to 100 parts by weight of the binder.

The printing magenta toner has the same configuration as the printing yellow toner, except that it contains, for example, the printing magenta dye instead of the printing yellow dye. The printing magenta dye is, for example, C.I. LReactiveRed3, C.I. LDisperseRed50 and C.I. LDisperseRed92 and the like. The content of the printing magenta dye is the same as the content of the printing yellow dye, for example.

The printing cyan toner has the same configuration as the printing yellow toner, except that it contains, for example, the printing cyan dye instead of the printing yellow dye. The printing cyan dye is, for example, C.I. LDisperseBlue60, C.I. LReactiveBlue15, C.I. LDisperseBlue359, C.I. LSolventBlue63, C.I. LDisperseBlue165 and CibacronTurquoiseBlueFGF-P. The content of the printing cyan dye is the same as the content of the printing yellow dye, for example.

The printing black toner has the same configuration as the printing yellow toner, except that it contains, for example, the printing black dye instead of the printing yellow dye. The printing black dye is, for example, C.I. LReactiveBlack5 and the like. However, the printing black dye may be, for example, a mixture of the printing yellow dye, the printing magenta dye, and the printing cyan dye. The content of the printing black dye is the same as the content of the printing yellow dye, for example.

[motion]
Next, an outline of the operation of the image forming apparatus 1 will be described with reference to FIG. FIG. 4 shows an example of the operation procedure of the image forming apparatus 1. The image forming apparatus 1 forms a toner image with respect to the medium M1 as follows, for example. The image forming apparatus 1 acquires a print job from the image transfer apparatus via the communication line (step S101). Then, the image forming apparatus 1 executes the printing process on the medium M1 by performing the following operations.

First, the control unit 70 generates a print image of the printing toner and a print image of the non-printing toner based on the image data included in the print job (steps S102 and S103). The control unit 70 further generates a print control signal for forming the printing toner image NTI (first image) based on the printing image of the printing toner, and also generates a printing control signal based on the printing image of the non-printing toner. A print control signal for forming a printing toner image CTI (second image) is generated.

Next, the control unit 70 inputs a print control signal to the developing units 30Y, 30M, 30C, 30K, and 30N. Then, the developing units 30Y, 30M, 30C, 30K, and 30N rotate the photoconductor drum 31 and apply a DC voltage to the surface of the photoconductor drum 31 to uniformly charge the surface of the photoconductor drum 31. Subsequently, the developing units 30Y, 30M, 30C, 30K, and 30N irradiate the surface of the photoconductor drum 31 with light from the light source 32 based on the print control signal input from the control unit 70, thereby causing the photoconductor drum 31. Of the surfaces of 31, the surface potential of the region irradiated with light is attenuated to form an electrostatic latent image.

When the upper roller 51 and the lower roller 52 reach a predetermined temperature, the medium supply unit 10 takes out the medium M1 stored in the medium supply tray 11 one by one from the uppermost portion by the pickup roller 12 and conveys the medium M1. Go out to route R. Next, the transport unit 20 corrects the skew of the medium M1 by the abutting process on the resist roller pair 21, and then transports the medium M1 to the resist roller pair 22. Subsequently, the transport unit 20 transports the medium M1 in the transport direction D in the transport path R by the resist roller pair 22.

The developing units 30Y, 30M, 30C, and 30K have the printing toner adhered to the surface (electrostatic latent image) of the photoconductor drum 31 and then the printing toner adhered to the surface (electrostatic latent image) of the photoconductor drum 31. Is transferred to the medium M1 transported in the transport direction D by the transfer rollers 40Y, 40M, 40C, 40K to form a printing toner image NTI on the medium M1. That is, the developing units 30Y, 30M, 30C, and 30K form the printing toner image NTI on the medium M1 by using the printing toner (printing imager). On the other hand, the developing unit 30N attaches the non-printing toner to the surface (electrostatic latent image) of the photoconductor drum 31 and then attaches the non-printing toner to the surface (electrostatic latent image) of the photoconductor drum 31. A non-printing toner image CTI is formed on the medium M1 by transferring the toner to the medium M1 transported in the transport direction D by the transfer roller 40N. That is, the developing unit 30N forms the non-printing toner image CTI on the medium M1 by using the non-printing toner (non-printing imager). In this way, the printing process on the medium M1 is executed.

Next, with reference to FIGS. 5 and 6, anron transfer using the medium M1 on which the printed toner image NTI and the non-printed toner image CTI are formed will be described. 5 (A) and 6 (A) show the state of iron transfer. 5 (B) and 5 (B) show an example of the transfer image Z1 formed on the medium M2 by iron transfer. 5 (A) and 5 (B) show the iron transfer when the amount of formation of the second region NTIb (mg / cm ² ) is such that the concentration duty is equal to or less than a predetermined threshold value. The situation is shown. 6 (A) and 6 (B) show iron transfer when the amount of formation of the second region NTIb (mg / cm ² ) is such that the concentration duty becomes larger than a predetermined threshold value. The state of is shown.

First, as shown in FIGS. 5 (A) and 6 (A), the medium M1 on which the printed toner image NTI and the non-printed toner image CTI are formed is opposed to the medium M2 to be transferred. At this time, the medium M1 is arranged so that the printed toner image NTI and the non-printed toner image CTI face the medium M2. Next, after the medium M1 is brought into close contact with the medium M2, heat energy is supplied to the medium M1 by pressing an iron against the medium M1. Conditions such as the temperature of the iron, the time for pressing the iron against the medium M2, and the weight supplied to the medium M1 via the iron can be arbitrarily set. As a result, as shown in FIGS. 5 (B) and 6 (B), the printing image agent is transferred from the printing toner image NTI to the medium M2 via the non-printing toner image CTI using thermal energy. .. As a result, an image (transfer image Z1) corresponding to the printing toner image NTI is formed on the medium M2. In this way, iron transfer is performed.

[effect]
Next, the effect of the image forming apparatus 1 will be described.

In recent years, after forming an image on a medium using a printing imager, the image is sublimated and transferred onto another medium such as a cloth by iron transfer. For example, an image is printed on a cloth for clothes such as a T-shirt by sublimation transfer. However, when sublimation transfer is used, a transferred image having a hue deviated from the hue on a medium such as paper may be formed on a medium such as a T-shirt.

On the other hand, in the present embodiment, when the non-printing toner image CTI is laminated on the medium M1 such as paper on the printing toner image NTI, the non-printing toner image depends on the amount of the printing image agent formed in the printing toner image NTI. The amount of CTI formed is controlled. As a result, at the time of anlon transfer, the printing image agent is transferred from the printing toner image NTI to the medium M2 via the non-printing toner image CTI adjusted to the above-mentioned formation amount, so that it is transferred on the medium M1 such as paper. A hue transfer image Z1 with reduced deviation from the hue can be formed on a medium M2 such as a T-shirt. Therefore, an image with high print quality (transfer image Z1) can be formed on a medium M2 such as a T-shirt.

Further, in the present embodiment, when the calculated density duty is equal to or less than a predetermined threshold value, the developing unit 30N forms an image covering the printed toner image NTI formed on the medium M1 as the non-printing toner image CTI. Is controlled. As a result, at the time of anlon transfer, the printing image agent is transferred from the printing toner image NTI to the medium M2 via the non-printing toner image CTI adjusted to the above-mentioned formation amount, so that it is transferred on the medium M1 such as paper. A hue transfer image Z1 with reduced deviation from the hue can be formed on a medium M2 such as a T-shirt. Therefore, an image with high print quality (transfer image Z1) can be formed on a medium M2 such as a T-shirt.

Further, in the present embodiment, when the threshold value is 60% regardless of the imaging agent of the printing imaging agent, the transferred image in which the color difference is reduced regardless of the imaging agent of the printing imaging agent. Z1 can be formed on a medium M2 such as a T-shirt. Therefore, an image with high print quality (transfer image Z1) can be formed on a medium M2 such as a T-shirt.

Further, in the present embodiment, when the threshold value is 40% regardless of the imager of the printing imager, the transfer with reduced gamut difference is reduced regardless of the imager of the printing imager. Image Z1 can be formed on a medium M2 such as a T-shirt. Therefore, an image with high print quality (transfer image Z1) can be formed on a medium M2 such as a T-shirt.

Further, in the present embodiment, when the calculated density duty is larger than the above threshold value, the developing unit 30N is used so as not to form the non-printing toner image CTI at the position where the printed toner image NTI is laminated with the first region NTIa. Is controlled. As a result, at the time of anlon transfer, in a place where the non-printing toner image CTI is not formed, the printing image agent is transferred from the printing toner image NTI to the medium M2 without passing through the non-printing toner image CTI. The transferred image Z1 of the hue in which the deviation from the hue on the medium M1 is reduced can be formed on the medium M2 such as a T-shirt. Therefore, an image with high print quality (transfer image Z1) can be formed on a medium M2 such as a T-shirt.

Further, in the present embodiment, when the threshold value is 60% regardless of the imaging agent of the printing imaging agent, the transferred image in which the color difference is reduced regardless of the imaging agent of the printing imaging agent. Z1 can be formed on a medium M2 such as a T-shirt. Therefore, an image with high print quality (transfer image Z1) can be formed on a medium M2 such as a T-shirt.

Further, in the present embodiment, when the threshold value is 40% regardless of the imager of the printing imager, the transfer with reduced gamut difference is reduced regardless of the imager of the printing imager. Image Z1 can be formed on a medium M2 such as a T-shirt. Therefore, an image with high print quality (transfer image Z1) can be formed on a medium M2 such as a T-shirt.

In the present embodiment, when the polymer compound contained in the non-printing toner image CTI contains a polyester resin, it is possible to capture an appropriate amount of the printing imager due to the high dyeability of the polyester resin. it can. Therefore, the deterioration of the print quality of the transferred image Z1 can be effectively suppressed.

In the present embodiment, if the printing image agent contained in the printing toner image NTI is a colored toner and the non-printing image agent contained in the non-printing toner image CTI is a clear toner, an error occurs. Therefore, even when the non-printed toner image CTI adheres to the medium M2, since the non-printed toner image CTI is transparent, it is possible to prevent deterioration of the print quality of the transferred image Z1.

<2. Example>
Next, an example of the image forming apparatus 1 according to the above embodiment will be described in comparison with a comparative example.

FIG. 7 shows the color of the image on the medium M1 such as paper and the color of the transfer image Z1 on the medium M2 such as a T-shirt when the amount of adhesion (formation amount) of the clear toner and the duty of the printing black are changed. It represents the color difference ΔE corresponding to the difference (deviation) in the L * a * b * space with and. FIG. 8 shows the color difference ΔE when the amount of adhesion (formation amount) of clear toner and the duty of printing yellow are changed. FIG. 9 shows the color difference ΔE when the amount of adhesion (formation amount) of the clear toner and the duty of the printing magenta are changed. FIG. 10 shows the color difference ΔE when the amount of adhesion (formation amount) of clear toner and the duty of printing cyan are changed. In FIGS. 7 to 10, "exc." Indicates that the color difference ΔE was smaller than when the clear toner was not provided, and "NG" was compared with the case where the clear toner was not provided. It indicates that the color difference ΔE is the same or larger.

FIG. 11 shows the color of the image on the medium M1 such as paper and the color of the transfer image Z1 on the medium M2 such as a T-shirt when the amount of adhesion (formation amount) of clear toner and the duty of printing yellow are changed. It represents the gamut difference corresponding to the difference (deviation) in the a * b * space with and. FIG. 12 shows the difference in gamut when the amount of adhesion (formation amount) of clear toner and the duty of printing magenta are changed. FIG. 13 shows the difference in gamut when the amount of adhesion (formation amount) of clear toner and the duty of printing cyan are changed. In FIGS. 11 to 13, "exc." Indicates that the gamut difference was smaller than when the clear toner was not provided, and "NG" was compared with the case where the clear toner was not provided. It indicates that the gamut difference is the same or larger.

From FIG. 7, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed of the printing black, and the density duty of the printing black (printing imager) is 80. When it is less than%, it can be seen that the color difference ΔE is improved. Further, from FIG. 8, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed in printing yellow, and the density duty of printing yellow (printing imager) When is 70% or less, it can be seen that the color difference ΔE is improved. Further, from FIG. 9, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed by the printing magenta, and the density duty of the printing magenta (printing magenta). When is 80% or less, it can be seen that the color difference ΔE is improved. Further, from FIG. 10, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed of the printing cyan, and the density duty of the printing cyan (printing imager) is formed. When is 60% or less, it can be seen that the color difference ΔE is improved. Summarizing the above, from FIGS. 7 to 10, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the concentration duty is 60% regardless of the printing imager of the printing toner. It can be seen that the color difference ΔE is improved in the following cases.

Further, from FIG. 7, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed of the printing black, and the density duty of the printing black (printing imager) When is larger than 80%, it can be seen that the deterioration of the color difference ΔE is suppressed by not providing the clear toner. Further, from FIG. 8, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed in printing yellow, and the density duty of printing yellow (printing imager) When is larger than 70%, it can be seen that the deterioration of the color difference ΔE is suppressed by not providing the clear toner. Further, from FIG. 9, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed by the printing magenta, and the density duty of the printing magenta (printing imager) When is larger than 80%, it can be seen that the deterioration of the color difference ΔE is suppressed by not providing the clear toner. Further, from FIG. 10, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed of the printing cyan, and the density duty of the printing cyan (printing imager) is formed. When is larger than 60%, it can be seen that the deterioration of the color difference ΔE is suppressed by not providing the clear toner. Summarizing the above, from FIGS. 7 to 10, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the concentration duty is 60% regardless of the printing imager of the printing toner. When it is larger than, it can be seen that the deterioration of the color difference ΔE is suppressed by not providing the clear toner.

Further, from FIG. 11, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed in printing yellow, and the density duty of printing yellow (printing imager) When is 60% or less, it can be seen that the gamut difference is improved. Further, from FIG. 12, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed by the printing magenta, and the concentration duty of the printing magenta (printing magenta). When is 70% or less, it can be seen that the gamut difference is improved. Further, from FIG. 13, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed of printing cyan, and the concentration duty of printing cyan (printing imager) When is 40% or less, it can be seen that the gamut difference is improved. Summarizing the above, from FIGS. 11 to 13, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the concentration duty is 40% regardless of the printing imager of the printing toner. It can be seen that the gamut difference is improved in the following cases.

Further, from FIG. 11, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed in printing yellow, and the density duty of printing yellow (printing imager) When is larger than 60%, it can be seen that the deterioration of the gamut difference is suppressed by not providing the clear toner. Further, from FIG. 12, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed by the printing magenta, and the concentration duty of the printing magenta (printing magenta). When is larger than 70%, it can be seen that the deterioration of the gamut difference is suppressed by not providing the clear toner. Further, from FIG. 13, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the printing toner image NTI is formed of printing cyan, and the concentration duty of printing cyan (printing imager) When is larger than 40%, it can be seen that the deterioration of the gamut difference is suppressed by not providing the clear toner. Summarizing the above, from FIGS. 11 to 13, when the adhesion amount (formation amount) of the clear toner is 0.16 mg / cm ² or more, the concentration duty is 40% regardless of the printing imager of the printing toner. When it is larger than, it can be seen that the deterioration of the gamut difference is suppressed by not providing the clear toner.

By the way, regarding the image density of the printed matter, the measurement conditions in the measuring instrument "X-rite 528" are set as follows. The measurement mode was set to "concentration measurement mode", the status was set to "status I", the white standard was set to "absolute white standard", "no polarizing filter" was set, and calibration was performed with a white calibration plate. The image density was later measured. "Status I" is a setting of a wavelength region to be evaluated, and is defined in "ISO5-3" Photographic technology-Density measurement-Part 3: Special connections ".

The amount of adhesion (formation amount) of the printing toner and the clear toner on the paper surface was measured by the following procedure.
(1) The image forming apparatus 1 and the medium M1 are left at a temperature of 23 ° C. and a humidity of 50% RH (NN environment) for 24 hours.
(2) Blank paper printing is performed one by one every 30 seconds for 10 minutes, the fixing portion 50 is warmed up, the heating member in the fixing portion 50 is 155 ± 5 ° C., and the upper roller 51 and the lower roller 52 are 135 ± 5 Heat to ° C.
(3) One sheet of the print pattern shown in FIG. 3 is printed (printed matter).
(4) Printing is restarted under the same printing conditions as when printing in step (3), and printing is stopped before the print pattern is passed through the fixing unit 50.
(5) The image density (NTIa portion) of the printing toner of the printed matter obtained in the procedure (3) is measured.
(6) Weigh the amount of printed toner adhered (NTIa portion) and the amount of clear toner adhered (difference between NTIb portion and NTIa portion) on the medium M1 on which the print pattern (toner image) obtained in step (4) was transferred. To do.

Incidentally, the medium on the amount of toner adhering (formation amount), expressed in weight per ^{1cm 2 (mg / cm 2)} , the medium on adhesion amount of the toner in the procedure (6) (formation amount) harvested as follows Will be done.

A double-sided tape is attached to the flat surface portion (area 1 cm ² ) of the metal jig, and a DC voltage of + 300 V is applied to the jig using an external power source. Then, the jig is pressed once against a predetermined position of the medium M1 on which the print pattern (toner image) obtained in the procedure (4) is transferred, and the cyan toner on the medium M1 is collected. Then, the weight of the jig to which the toner is attached is weighed with an electronic balance (Sartorius, CAP225D). The amount of adhesion (formation amount) (mg / cm ² ) on the medium per unit area is calculated from the weight difference of the jig before and after toner collection. The procedure described in (2) to (6) above was repeated three times, and the average value was taken as the amount of toner adhered (formed amount).

The amount of toner adhered to the medium (formation amount) had a substantially proportional relationship with the density duty of the toner, as shown in FIG. 14, for example. At this time, the image density was 1.64 when the amount (formation amount) of the printing black adhered to the medium was 0.58 mg / cm ^2. When the amount of printing yellow adhered to the medium (formation amount) was 0.57 mg / cm ² , the image density was 1.67. The image density was 1.57 when the amount (formation amount) of the printing magenta adhered to the medium was 0.56 mg / cm ^2. The image density was 1.31 when the amount of printed cyan attached (formed) on the medium was 0.49 mg / cm ^2.

The printed matter obtained above was thermally transferred under the conditions shown below.

As the medium M1, A4 printer paper (excellent white, size = 297 mm × 210 mm) manufactured by Oki Data Corporation was used. Thermal transfer was performed using a polyester T-shirt (manufactured by glimmer) as the medium M2. The thermal transfer was carried out under the conditions of a temperature of 200 ° C., a thermal transfer time of 1 minute, and a press pressure of 142 g / cm ^2. The hue of the medium M2 after thermal transfer was measured with X-rite 528 (manufactured by X-rite), and the L * value, a * value, and b * value of the medium M2 before thermal transfer were determined from the following formulas. The color difference ΔE was obtained from the difference between the L * value, the a * value, and the b * value of the medium M2 after thermal transfer when the clear toner was provided. The color difference ΔE is calculated by the following formula.
ΔE = {(L * -L * Ref.) ² + (a * -a * Ref.) ²
+ (B * -b * Ref.) ² } ^1/2

The hue of the medium M2 was measured by the measuring instrument "X-rite 528". Specifically, the measurement conditions in the measuring instrument "X-rite 528" were set as follows. The measurement mode is "L * a * b * color system measurement mode", the status is "Status I", the observation light source (illuminant) is "D50" (light source with a color temperature of about 5000K), and the viewing angle (observation field). Was set to "2 °", the white standard was set to "absolute white standard", and "no polarizing filter" was set, and the color difference was measured after calibration with a white calibration plate.

<3. Modification example>
Next, a modified example of the image forming apparatus 1 according to the above embodiment will be described.

[Modification example A]
In the above-described embodiment and its modification, the image forming apparatus 1 is a direct transfer type printer that directly forms an image with respect to the medium M to be discharged to the outside. However, the image forming apparatus 1 may be, for example, an intermediate transfer type printer that forms an image on the medium M1 by using the intermediate transfer belt 41 as shown in FIG. In this modification, the developing units 30N, 30Y, 30M, 30C, and 30K are arranged in this order from upstream to downstream in the transport direction D of the intermediate transfer belt 41, for example. That is, the developing unit 30N is arranged upstream of the developing units 30Y, 30M, 30C, and 30K in the transport direction D of the intermediate transfer belt 41 by the transport unit 20.

In this modification, the transfer unit 40 includes, for example, five transfer rollers 40Y, 40M, 40C, 40K, 40N, an intermediate transfer belt 41, a drive roller 42, a driven roller 43, a backup roller 44, and two. It has a next transfer roller 45 and a cleaning blade 46. In this modification, the intermediate transfer belt 41 corresponds to a specific example of the "intermediate transfer medium" of the present invention. The drive roller 42, the driven roller 43, and the backup roller 44 correspond to a specific example of the "first transport unit" of the present invention. The five transfer rollers 40Y, 40M, 40C, 40K, and 40N correspond to a specific example of the "first transfer unit" of the present invention. The secondary transfer roller 45 corresponds to a specific example of the "second transfer unit" of the present invention. The discharge unit 60 corresponds to a specific example of the “discharge unit” of the present invention.

The intermediate transfer belt 41 is a medium in which the toner is temporarily transferred before the toner is transferred to the medium M1, and is, for example, an endless elastic belt. The medium M1 corresponds to a specific example of the "medium" of the present invention. The intermediate transfer belt 41 contains any one or more of the polymer materials such as polyimide. The intermediate transfer belt 41 can be moved according to the rotation of the drive roller 42, for example, in a state of being stretched by each of the drive roller 42, the driven roller 43, and the backup roller 44.

The drive roller 42, for example, is controlled by the control unit 70 and rotates in a direction in which the intermediate transfer belt 41 is conveyed in the direction from 30N to 30K. The driven roller 43 and the backup roller 44 can rotate according to the rotation of the drive roller 42, for example. The drive roller 42, the driven roller 43, and the backup roller 44 convey the intermediate transfer belt 41. The five transfer rollers 40Y, 40M, 40C, 40K, and 40N transfer the toner attached to the electrostatic latent image to the intermediate transfer belt 41 (primary transfer). The transfer roller module composed of four transfer rollers 40Y, 40M, 40C, and 40K transfers the printing toner image NTI to the intermediate transfer belt 41. The transfer roller 40N transfers the unprinted toner image CTI to the intermediate transfer belt 41. The five transfer rollers 40Y, 40M, 40C, 40K, and 40N are pressed against the photoconductor drum 31 of the developing units 30Y, 30M, 30C, 30K, and 30N via the intermediate transfer belt 41. The developing unit 30N is arranged upstream of the non-printing toner image CTI in the direction in which the intermediate transfer belt 41 is conveyed in the direction from 30N to 30K in the positional relationship with the printing toner image NTI.

The secondary transfer roller 45 transfers (secondary transfer) the toner (printed toner image NTI and non-printed toner image CTI) transferred to the intermediate transfer belt 41 to the medium M1. The secondary transfer roller 45 is pressure-welded to the backup roller 44, and includes, for example, a metal core material and an elastic layer such as a foam rubber layer that covers the outer peripheral surface of the core material. The secondary transfer roller 45, for example, is controlled by the control unit 70 and rotates in a direction in which the intermediate transfer belt 41 is conveyed in the direction from 30Y to 30N. The cleaning blade 46 is pressed against the intermediate transfer belt 41, and scrapes off unnecessary foreign matter such as toner remaining on the surface of the intermediate transfer belt 41. The discharge unit 60 discharges the medium M1 to which the printed toner image NTI and the non-printed toner image CTI are transferred to the outside.

(Structure of Printed Toner Image NTI and Non-Printed Toner Image CTI)
FIG. 16 shows an example of the printed toner image NTI and the non-printed toner image CTI formed on the intermediate transfer belt 41. FIG. 16A shows a plan configuration example of the printed toner image NTI and the non-printed toner image CTI formed on the intermediate transfer belt 41. FIG. 16B shows an example of a cross-sectional configuration taken along the line AA of FIG. 16A. In FIGS. 16A and 16B, the first region in ^{which the printing toner image NTI has a relatively large amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI. It is composed of NTIa and a second region NTIb in which the ^{amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI is relatively small. In FIGS. 16A and 16B, the amount of formation (mg / cm ² ) of the first region NTIa and the second region NTIb is a value such that the concentration duty is equal to or less than a predetermined threshold value.

The printing toner image NTI is formed on the intermediate transfer belt 41 and in the region corresponding to the print region α of the medium M1 on the intermediate transfer belt 41. The printed toner image NTI is formed on the non-printed toner image CTI. The printed toner image NTI and the non-printed toner image CTI are transferred from the intermediate transfer belt 41 to the medium M1 as shown in FIGS. 17 (A) and 17 (B), for example. As a result, the non-printing toner image CTI is arranged so as to cover the printing toner image NTI on the medium M1.

FIG. 18 shows an example of the printed toner image NTI and the non-printed toner image CTI formed on the intermediate transfer belt 41. FIG. 18A shows a plan configuration example of the printed toner image NTI and the non-printed toner image CTI formed on the intermediate transfer belt 411. FIG. 18B shows an example of a cross-sectional configuration taken along the line AA of FIG. 18A. In FIGS. 18A and 18B, the first region in ^{which the printing toner image NTI has a relatively large amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI. It is composed of NTIa and a second region NTIb in which the ^{amount (mg / cm 2} ) of the printing toner (printing imager) formed in the printing toner image NTI is relatively small. In FIGS. 18A and 18B, the amount of formation of the first region NTIa (mg / cm ² ) has a value such that the concentration duty becomes larger than a predetermined threshold value, and the second region NTIb The amount of formation (mg / cm ² ) is such that the concentration duty becomes smaller than a predetermined threshold value.

The unprinted toner image CTI is formed on the intermediate transfer belt 41. The non-printing toner image CTI is formed at a position of the printing toner image NTI facing the second region NTIb. Of the printed toner image NTI, the first region NTIa is formed on the intermediate transfer belt 41 without passing through the non-printed toner image CTI. Of the printed toner image NTI, the second region NTIb is formed on the intermediate transfer belt 41 via the non-printed toner image CTI. The printed toner image NTI and the non-printed toner image CTI are transferred from the intermediate transfer belt 41 to the medium M1 as shown in FIGS. 19A and 19B, for example. At this time, the non-printing toner image CTI is on the medium M1 and is not in contact with the first region NTIa of the printing toner image NTI formed on the medium M1 and does not cover the first region NTIa. .. The non-printing toner image CTI is formed, for example, in contact with the surface of the second region NTIb of the printing toner image NTI.

[motion]
Next, an outline of the operation of the image forming apparatus 1 will be described with reference to FIG. FIG. 20 shows an example of the operation procedure of the image forming apparatus 1. The image forming apparatus 1 forms a toner image with respect to the medium M1 as follows, for example. The image forming apparatus 1 acquires a print job from the image transfer apparatus via the communication line (step S201). Then, the image forming apparatus 1 executes the printing process on the medium M1 by performing the following operations.

First, the control unit 70 generates a print image of the printing toner and a print image of the non-printing toner based on the image data included in the print job (steps S202 and S203). The control unit 70 further generates a print control signal for forming the printing toner image NTI (first image) based on the printing image of the printing toner, and also generates a printing control signal based on the printing image of the non-printing toner. A print control signal for forming a printing toner image CTI (second image) is generated.

Next, the control unit 70 inputs a print control signal to the developing units 30Y, 30M, 30C, 30K, and 30N. Then, the developing units 30Y, 30M, 30C, 30K, and 30N rotate the photoconductor drum 31 and apply a DC voltage to the surface of the photoconductor drum 31 to uniformly charge the surface of the photoconductor drum 31. Subsequently, the developing units 30Y, 30M, 30C, 30K, and 30N irradiate the surface of the photoconductor drum 31 with light from the light source 32 based on the print control signal input from the control unit 70, thereby causing the photoconductor drum 31. Of the surfaces of 31, the surface potential of the region irradiated with light is attenuated to form an electrostatic latent image.

When the upper roller 51 and the lower roller 52 reach a predetermined temperature, the medium supply unit 10 takes out the medium M1 stored in the medium supply tray 11 one by one from the uppermost portion by the pickup roller 12 and conveys the medium M1. Go out to route R. Then, the intermediate transfer belt 41 starts to move.

The developing unit 30N attaches the non-printing toner to the surface (electrostatic latent image) of the photoconductor drum 31 and then transfers the non-printing toner adhered to the surface (electrostatic latent image) of the photoconductor drum 31 to a transfer roller. The unprinted toner image CTI is printed on the intermediate transfer belt 41 by transferring it to the intermediate transfer belt 41 conveyed in the transfer direction D by 40N (step S204). That is, the developing unit 30N uses the non-printing toner (non-printing imager) to form the non-printing toner image CTI on the intermediate transfer belt 41. On the other hand, the developing units 30Y, 30M, 30C, and 30K adhered the printing toner to the surface (electrostatic latent image) of the photoconductor drum 31 and then adhered to the surface (electrostatic latent image) of the photoconductor drum 31. By transferring the printing toner to the intermediate transfer belt 41 conveyed in the transfer direction D by the transfer rollers 40Y, 40M, 40C, 40K, the printing toner image NTI is printed on the intermediate transfer belt 41 (step S205). The developing units 30Y, 30M, 30C, and 30K form a printing toner image NTI on the intermediate transfer belt 41 using a printing toner (printing imager). Then, the printed toner image NTI and the non-printed toner image CTI are transferred (secondary transfer) from the intermediate transfer belt 41 to the medium M1 using the transfer unit 40. In this way, the printing process on the medium M1 is executed.

As described above, in this modification, the image forming apparatus 1 is an intermediate transfer type printer. Even in such a case, the same effect as that of the above-described embodiment and its modification can be obtained.

[Modification B]
In the above embodiment and its modification, the image forming apparatus 1 is an electrophotographic full-color printer. However, in the above-described embodiment and its modifications, the image forming apparatus 1 may be, for example, an inkjet full-color printer. In this case, ink is applied instead of toner. Specifically, the printing ink is applied instead of the printing toner. The printing ink is a colored ink that can be transferred to the medium M2 described later by utilizing the sublimation transferability at the time of heating. Non-printing ink is applied instead of non-printing toner. The printing ink is, for example, a clear ink. Even in this case, the same effect as that of the above-described embodiment and its modification can be obtained.

[Modification C]
In the above-described embodiment and its modifications, the present invention has been applied to the image forming apparatus 1, but it may be applied to a copier, a scanner, a facsimile, or a multifunction device including these functions. Even in these cases, the same effects as those of the above-described embodiment and its modifications can be obtained.

[Modification D]
The series of processes described in the above-described embodiment and its modification may be performed by hardware (circuit) or software (program). When the above series of processes is performed by software, the software is composed of a group of programs for executing each function by a computer. Each program may be used by being preliminarily incorporated in the computer, for example, or may be installed and used in the computer from a network or a recording medium.

1 ... Image forming device, 1A ... Housing, 1S ... Storage unit, 10 ... Medium supply unit, 11 ... Medium supply tray, 12 ... Pickup roller, 20 ... Conveying unit, 21,22 ... Resist roller pair, 30 ... Image forming Unit, 30Y, 30M, 30C, 30K, 30N ... Development unit, 31 ... Photoreceptor drum, 32 ... Light source, 40 ... Transfer unit, 40Y, 40M, 40C, 40K, 40N ... Transfer roller, 41 ... Intermediate transfer belt, 42 ... Drive roller, 43 ... Driven roller, 44 ... Backup roller, 45 ... Secondary transfer roller, 50 ... Fixing part, 51 ... Upper roller, 52 ... Lower roller, 60 ... Discharge part, 61, 62, 63 ... Conveying roller pair , 70 ... Control unit, CTI ... Non-printing toner image, D ... Transport direction, NTI ... Printing toner image, NTIa ... High density part, NTIb ... Low density part, M1, M2 ... Medium, α ... Print area, Z1 ... Transfer image.

Claims (12)

A first image forming unit that visualizes the first image using a printing imager, and a first image forming unit.
A second image forming unit that visualizes the second image using a non-printing imager, and a second image forming unit.
A control unit that controls the first image forming unit and the second image forming unit is provided.
When the second image is laminated on the medium with the first image, the control unit controls the amount of the non-printing image forming agent formed according to the amount of the printing imaging agent formed. apparatus. The first image forming unit and the second image forming unit are arranged at positions where the first image and the second image can be laminated in this order on the medium discharged to the outside. The image forming apparatus according to claim 1. The printing and imaging agent contains a colorant that has a relative sublimation property as compared with the non-printing and imaging agent.
The image forming apparatus according to claim 1 or 2, wherein the non-printing imager is made of a material having a relatively low sublimation property as compared with the colorant. The image forming apparatus according to claim 3, wherein the non-printing image forming agent is an image forming agent to be dyed containing a polymer compound that can be dyed by the coloring agent. The image forming apparatus according to claim 4, wherein the polymer compound contains a polyester resin. The printing imager is a colored toner or a colored ink.
The image forming apparatus according to any one of claims 1 to 5, wherein the non-printing imager is a clear toner or a clear ink. When the density duty of the printing imaging agent in the first image is equal to or less than a predetermined threshold value, the control unit determines the density duty of the printing imaging agent in the first image on the medium. The image formation according to any one of claims 1 to 6, which controls the second image forming unit so as to visualize the second image at a position where the second image is overlapped with a portion below the threshold value. apparatus. When the density duty of the printing imaging agent in the first image is larger than the threshold value, the control unit determines the density duty of the printing imaging agent in the first image on the medium. The image forming apparatus according to claim 7, wherein the second image forming unit is controlled so that the second image is not visualized at a position where the second image is overlapped with a portion larger than the threshold value. The image forming apparatus according to claim 7 or 8, wherein the threshold value is 60% regardless of the imaging agent of the printing imaging agent. The image forming apparatus according to claim 7 or 8, wherein the second threshold value is 40% regardless of the imaging agent of the printing imaging agent. Further provided with a transport unit for transporting the medium,
The first image forming unit visualizes the first image directly on the medium.
The second image forming unit visualizes the second image directly on the medium.
The second image-forming unit is located downstream of the first image-forming unit in the transport direction of the medium by the transport unit, according to any one of claims 1 to 10. Image forming device. The first transport section that transports the intermediate transfer medium and
A first transfer unit that transfers the first image and the second image to the intermediate transfer medium, and
A second transfer unit for transferring the first image and the second image from the intermediate transfer medium to the medium is further provided.
Any one of claims 1 to 10 in which the second image forming unit is arranged upstream of the first image forming unit in the transport direction of the intermediate transfer medium by the first transporting section. The image forming apparatus according to the section.

Images