JP7447556B2 - Image forming apparatus, image forming apparatus control method, and image forming apparatus control program - Google Patents

Description

The present invention relates to an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program.

An image forming apparatus includes a light irradiator for an image reading device to inspect a formed image, and an inkjet recording device includes a light irradiator for irradiating ultraviolet light for curing ink. Regarding such image forming apparatuses, various techniques have been disclosed for irradiating light with stable intensity from a light irradiator in order to form highly accurate images.

One of these techniques is as follows. That is, an irradiation step of irradiating the irradiation light onto a filter that is provided at a light shielding position to block the irradiation light irradiated by the light irradiator and is capable of transmitting light in a predetermined wavelength range with a predetermined transmittance, and a transmission step that transmits the irradiation light through the filter. and a determination step of correcting the intensity of the irradiated light in accordance with an instruction based on the intensity of the light. Thereby, the irradiation intensity of the irradiation light emitted by the light irradiator can be corrected in a predetermined wavelength range using transmitted light that has been reduced to a predetermined intensity (Patent Document 1 below) reference).

Japanese Patent Application Publication No. 2016-124244

According to the above technology, by attenuating the irradiated light from the light irradiator using a filter, even if the intensity of the irradiated light is too strong, the irradiated light can be reduced without saturating the photodetector. intensity can be detected. However, in such a technique, when the filter becomes dirty, it becomes difficult to attenuate the irradiation light emitted from the light irradiator as initially due to the dirt on the filter itself. For this reason, it is difficult to continue accurately detecting the intensity of the irradiation light emitted from the light irradiator.

Therefore, the present invention provides an image forming apparatus that is capable of continuously detecting the light intensity of the irradiated light emitted from the light irradiator without saturating it in the photodetector, and thereby capable of forming images with stable accuracy. An object of the present invention is to provide a method for controlling an image forming apparatus, and a control program for the image forming apparatus.

In order to achieve such an object, the present invention includes an image forming section that forms an image on a recording medium, a light irradiation device that irradiates the recording medium with light, and a device that allows the irradiation light irradiated from the light irradiation device to pass through. a light detection section having a light shielding member and a photodetector that detects the light intensity of the irradiation light attenuated by the light shielding member; and a control section that controls driving of the image forming section and the light irradiation device. , the light shielding member has at least one aperture hole, and the photodetector is an image forming device that detects the light intensity of the irradiated light emitted from the light irradiation device and passed through the aperture hole.

According to the present invention, it is possible to continue to detect the light intensity of the irradiation light emitted from the light irradiator with high precision without saturating the photodetector, thereby enabling image formation with stable accuracy. An image forming apparatus, a method for controlling an image forming apparatus, and a control program for an image forming apparatus can be provided.

FIG. 1 is a configuration diagram of an image forming apparatus according to a first embodiment. FIG. 1 is an enlarged configuration diagram of main parts of an image forming apparatus according to a first embodiment. FIG. 2 is a plan view illustrating a light detection section of the image forming apparatus according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a light detection section of the image forming apparatus according to the first embodiment. FIG. 2 is a configuration diagram of a main part of a light detection section of the image forming apparatus according to the first embodiment. FIG. 1 is a block diagram showing the configuration of an image forming apparatus according to a first embodiment. 3 is a flowchart illustrating a method of controlling the image forming apparatus according to the first embodiment. FIG. 2 is a diagram (part 1) illustrating a method of controlling the image forming apparatus according to the first embodiment. FIG. 2 is a diagram (part 2) illustrating a method of controlling the image forming apparatus according to the first embodiment; It is a graph explaining the light receiving sensitivity characteristic of the light receiving element which comprises a photodetector. FIG. 3 is a configuration diagram (part 1) illustrating a modification of the first embodiment. FIG. 7 is a configuration diagram (Part 2) illustrating a modification of the first embodiment. FIG. 2 is a configuration diagram (part 1) illustrating an image forming apparatus according to a second embodiment. FIG. 2 is a configuration diagram (Part 2) illustrating an image forming apparatus according to a second embodiment. FIG. 3 is a configuration diagram (part 1) illustrating an image forming apparatus according to a third embodiment. FIG. 3 is a configuration diagram (part 2) illustrating an image forming apparatus according to a third embodiment. 7 is a graph illustrating the light-receiving sensitivity characteristics of a photodetector included in an image forming apparatus according to a third embodiment.

Embodiments of an image forming apparatus, an image forming apparatus control method, and an image forming apparatus control program to which the present invention is applied will be described below. In each of the embodiments described below, an inkjet image forming apparatus will be described as an example of the image forming apparatus, but the present invention is not limited to this and may be applied to an electrophotographic image forming apparatus. It is also applicable to Moreover, in each embodiment, common components are given the same reference numerals, and overlapping explanations will be omitted.

≪First embodiment≫
FIG. 1 is a configuration diagram of an image forming apparatus 1 according to the first embodiment. Further, FIG. 2 is an enlarged configuration diagram of main parts of the image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 shown in these figures is of an inkjet type, and includes a medium supply section 10, an image forming section 20, a medium discharge section 30, and a control device 40, and is configured to form an image on a recording medium P. Execute. The recording medium P is in the form of a sheet, and in addition to paper such as plain paper or coated paper, it can also be made of various materials capable of fixing ink that has landed on the main surface of the sheet, such as cloth or sheet-like resin. A medium can be used. The configuration of each part of such an image forming apparatus 1 will be explained below.

<Medium supply unit 10>
The medium supply unit 10 includes a paper feed tray 11 that stores the recording medium P, and a supply unit 12 that transports the recording medium P from the paper feed tray 11 to the image forming unit 20. Note that the recording medium P conveyed from the paper feed tray 11 to the image forming section 20 is further conveyed from the image forming section 20 to a medium discharge section 30. For this reason, the following description will be made here assuming that the direction in which the medium supply section 10, image forming section 20, and medium discharge section 30 are arranged is the transport direction x of the recording medium P.

<Image forming section 20>
The image forming section 20 includes a conveyance drum 21, a delivery unit 22, a heating section 23, a head unit 24, a curing light irradiation device 25, an image reading device 26, a delivery section 27, and further includes the first embodiment. and a characteristic photodetection section 100. These configurations are as follows.

[Transport drum 21]
The transport drum 21 has a cylindrical shape, and its side peripheral surface serves as a transport surface 21a that attracts and holds the recording medium P. The transport drum 21 rotates in one rotational direction x1 (counterclockwise in the drawing) about a cylindrical central axis as a rotation axis while holding the recording medium P on its transport surface 21a. Thereby, the transport drum 21 functions as a medium transport section that transports the recording medium P held by suction on the transport surface 21a in the rotational direction x1 along a path along the transport surface 21a.

The conveyance drum 21 is made up of a plurality of blocks extending in the direction of the rotation axis, and is configured to hold the recording medium P in each block. Further, the conveyance drum 21 has a groove-shaped recess 21b formed at the joint between each block. In the illustrated example, the conveyance drum 21 is composed of three blocks, and has three recesses 21b corresponding to the joints of these blocks.

These recesses 21b extend along the rotation axis on the conveyance surface 21a, and are arranged across the rotation axis direction of the conveyance drum 21. One of these recesses 21b accommodates a photodetector 100 of each embodiment described below.

[Delivery unit 22]
The delivery unit 22 is provided at a position between the medium supply section 10 and the transport drum 21. The transfer unit 22 holds and picks up one end of the recording medium P conveyed from the supply section 12 of the medium supply section 10, and transfers the recording medium P to the conveyance surface 21a of the conveyance drum 21.

[Heating section 23]
The heating unit 23 is provided on the downstream side of the delivery unit 22 in the conveyance direction x of the recording medium P and the rotation direction x1 of the conveyance drum 21, and is configured to maintain the temperature of the recording medium P conveyed by the conveyance drum 21 within a predetermined range. The recording medium P is heated so that Such a heating unit 23 is configured using, for example, an infrared heater or the like, and heating is performed by energizing the infrared heater based on instructions from the control device 40.

[Head unit 24]
The head unit 24 is an ink supply device provided downstream of the heating section 23 in the conveyance direction x of the recording medium P and the rotation direction x1 of the conveyance drum 21. This head unit injects ink onto the recording medium P held by the transport drum 21 at an appropriate timing according to the rotation of the transport drum 21. In the image forming apparatus 1 according to the present embodiment, four head units 24 respectively corresponding to four color inks of yellow (Y), magenta (M), cyan (C), and black (K), as an example, are arranged on a recording medium. They are arranged in order from the upstream side in the conveyance direction x of P at predetermined intervals.

Each head unit 24 has an ink ejection surface on which nozzle openings of a plurality of ink heads are arranged, and is arranged so that this ink ejection surface faces the transport surface 21a of the transport drum 21. Each head unit 24 is, for example, a single-pass type device in which an ink ejection surface is arranged over the entire area in the axial direction of the recording medium P conveyed by the conveyance drum 21.

[Curing light irradiation device 25]
The curing light irradiation device 25 is one of the light irradiation devices, and is provided downstream of the head unit 24 in the transport direction x of the recording medium P. The curing light irradiation device 25 irradiates the recording medium P held on the transport surface 21a of the transport drum 21 with energy rays such as ultraviolet rays, thereby curing and fixing the ink ejected onto the recording medium P. Such a curing light irradiation device 25 has a plurality of light emitting elements arranged across the rotation axis direction of the conveyance drum 21.

Each light emitting element is, for example, an LED, and emits, for example, ultraviolet light as light having a wavelength suitable for curing the ink. Such light emitting elements are arranged in a two-dimensional matrix along the direction of the rotation axis of the transport drum 21, thereby forming a light emitting surface extending along the direction of the rotation axis of the transport drum 21.

The curing light irradiation device 25 also includes a temperature detector for detecting the internal temperature of the device.

[Image reading device 26]
The image reading device 26 is provided downstream of the curing light irradiation device 25 in the transport direction x of the recording medium P, and reads an image formed on the surface of the recording medium P. Such an image reading device 26 includes a light irradiation device 26a arranged along the axial direction of the transport drum 21, and an imaging device 26b (shown only in FIG. 2) such as a CCD or CMOS sensor, and controls the driving of these devices individually. and a drive circuit (not shown). Note that the axial direction of the transport drum 21 is perpendicular to the transport direction x, and is the transport width direction.

Among these, the light irradiation device 26a has a plurality of light emitting elements arranged along the rotation axis direction of the transport drum 21. Each light emitting element is, for example, an LED, and emits white light for imaging. Such light emitting elements are arranged in a two-dimensional matrix along the direction of the rotation axis of the transport drum 21, thereby forming a light emitting surface extending along the direction of the rotation axis of the transport drum 21. Further, the imaging device 26b is an arrangement of optical sensors for reading an image formed on the surface of the recording medium P.

The light irradiation device 26a also includes a temperature detector for detecting the internal temperature of the device.

[Delivery Department 27]
The delivery section 27 is located between the conveyance drum 21 and the medium discharge section 30, and is provided on the downstream side of the image reading device 26 in the conveyance direction x of the recording medium P. The delivery section 27 holds and picks up one end of the recording medium P being conveyed on the conveyance surface 21 a of the conveyance drum 21 , and sends the recording medium P onto the paper discharge tray 31 of the medium discharge section 30 .

[Photodetector 100]
The light detection unit 100 is for detecting the light intensity of the irradiation light irradiated from the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26. Such a light detection unit 100 is housed in a recess 21b disposed along the conveyance surface 21a of the conveyance drum 21, and when the conveyance drum 21 rotates, the light irradiation device of the curing light irradiation device 25 and the light irradiation device of the image reading device 26 is activated. 26a. Such a photodetector 100 includes a light shielding member 101 and a photodetector 102.

FIG. 3 is a plan view illustrating the photodetection section 100 of the image forming apparatus according to the first embodiment, and is a plan view of the photodetection section 100 viewed from the curing light irradiation device 25 and image reading device 26 side of FIG. 2. It is. Further, FIG. 4 is a sectional view illustrating the light detection unit 100 of the image forming apparatus according to the first embodiment, and is a sectional view of the light detection unit 100 in a direction along the recess 21b of the transport drum 21 shown in FIG. It is. Hereinafter, the configuration of each part of the light detection section 100 in the image forming apparatus 1 of the first embodiment will be explained based on FIGS. 3 and 4 while referring to FIG. 2.

- Light shielding member 101 -
The light shielding member 101 is a plate-shaped member provided with at least one aperture hole 101a. In the illustrated example, a configuration in which a plurality of aperture holes 101a are provided is shown. These aperture holes 101a are for passing the irradiation light irradiated from the curing light irradiation device 25 and the irradiation light irradiated from the light irradiation device 26a of the image reading device 26. These throttle holes 101a are preferably arranged evenly in the direction along the rotation axis of the conveyance drum 21.

Each aperture hole 101a has an opening diameter [φ] that is large enough to diffract the irradiation light irradiated from the curing light irradiation device 25 and the irradiation light irradiated from the light irradiation device 26a of the image reading device 26. is preferred.

-Photodetector 102-
The photodetector 102 has a configuration in which a plurality of light receiving elements 102a are provided on the light shielding member 101 side of a plate-shaped member. These light receiving elements 102a are arranged in a 1:1 correspondence with the aperture hole 101a of the light shielding member 101, and receive light passing through the aperture hole 101a in a 1:1 ratio. The light receiving element 102a is an element that converts the intensity of the received light into an electrical signal, and is, for example, a photodiode. Such a light receiving element 102a is intended to detect light intensity, and there is no need to separate the received light into wavelengths.

Further, it is preferable that the light receiving element 102a is disposed at a position shifted from the aperture hole 101a without overlapping the aperture hole 101a when the light detection unit 100 is viewed from the normal direction to the light shielding member 101. .

FIG. 5 is a configuration diagram of a main part of the photodetection section 100 of the image forming apparatus 1 according to the first embodiment, and corresponds to the AA cross section in FIG. 3 and the AA cross section in FIG. 4. It is. As shown in FIG. 5, the irradiation light H from the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 is diffracted by passing through the aperture hole 101a of the light shielding member 101, and is reflected on the back side of the aperture hole 101a. Go around. Therefore, the light receiving element 102a of the photodetector 102 is arranged at a position shifted from the aperture hole 101a within a range where it can receive the irradiation light H diffracted by passing through the aperture hole 101a.

Although the direction in which the light receiving element 102a is shifted relative to the aperture hole 101a is not limited, in the illustrated example, it is set to the rotation direction x1 of the conveyance drum 21.

By arranging the light receiving element 102a at such a position, the irradiation light H reaching the light receiving element 102a is attenuated, and ink mist and debris from the recording medium P are directed to the light receiving element 102a through the aperture hole 101a. It can prevent adhesion.

Further, the light receiving element 102a is positioned close to the light shielding member 101 to such an extent that it does not receive the irradiated light H that has been diffracted by passing through another aperture hole 101a disposed close to the corresponding aperture hole 101a. It is preferable that the Thereby, the irradiation light H from the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 can be reliably separated and received by the light receiving element 102a.

<Media discharge section 30>
Returning to FIG. 1, the medium discharge section 30 has a plate-shaped paper discharge tray 31 on which the recording medium P discharged from the image forming section 20 is placed, and stores the recording medium P after image formation.

<Control device 40>
The control device 40 controls the driving of each member constituting the medium supply section 10, the image forming section 20, and the medium discharge section 30. FIG. 6 is a block diagram showing the configuration of the image forming apparatus 1 according to the first embodiment, and is a diagram for explaining the configuration of the control device 40. As shown in FIG. As shown in FIGS. 1 and 6, the control device 40 includes an operation section 41, a display section 42, and a control section 43, and includes a medium supply section 10, an image forming section 20, and a medium discharge section 30. It is connected.

[Operation unit 41]
Of these, the operation section 41 is a section for inputting various settings related to image formation performed using this image forming apparatus 1. Such an operation section 41 may be a touch panel provided integrally with the display section 42, or may have operation buttons provided separately from the display section 42. Furthermore, such an operation unit 41 may be a personal computer capable of communicating with a control unit 43 to be described later to exchange data, or an external device such as a printer controller.

[Display section 42]
The display section 42 displays the contents of the operation on the operation section 41, the contents set according to the operation on the operation section 41, and other information according to the next instruction from the control section 43. This display unit 42 is a notification unit that performs notifications according to instructions from the control unit 43.

[Control unit 43]
The control unit 43 controls the processing of image data input from an external device and the operation of each drive part of the image forming apparatus 1 based on operations on the operation unit 41 . Such a control unit 43 is configured by a computer. A computer is hardware used as a so-called computer. A computer includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and other memories. Furthermore, the computer includes a non-volatile storage unit and a network interface.

The control section 43 forms an image on the recording medium P by controlling the driving of each section constituting the medium supply section 10, the image forming section 20, and the medium ejection section 30. Moreover, one of the controls executed by this control unit 43 is a characteristic control described below. Such a characteristic control procedure is a control program for controlling the operation of each part of the image forming apparatus 1, and is a program stored in advance in ROM or loaded from an external device into RAM or nonvolatile storage. This is a saved program. This control program causes the computer to execute the steps described in the image forming apparatus control method below.

Such a control section 43 includes a light intensity determination section 43a, a correction processing section 43b, and a drive control section 43c as functional elements. Next, the functions of these components will be explained.

-Light intensity determination section 43a-
The light intensity determination unit 43a determines in advance the light intensity of the irradiation light from the light irradiation device 26a of the curing light irradiation device 25 and the image reading device 26, based on the signals from each light receiving element 102a provided in the image forming unit 20. A determination is made as to whether or not the threshold value is greater than or equal to the set threshold value. Further, the light intensity determination unit 43a determines that when the light intensity of the irradiation light from the light irradiation device 26a of the curing light irradiation device 25 and the image reading device 26 is lower than the threshold value, the decrease in light intensity is within an allowable range that can be corrected. A judgment is made as to whether or not.

The light intensity determination unit 43a retains a threshold value that serves as a reference when making the above determinations, and a threshold value that serves as an allowable range. These threshold values are held in the light intensity determination unit 43a as values corresponding to each of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26. Further, these values are held in the light intensity determination unit 43a as values corresponding to the internal temperatures of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26. The internal temperature of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 may be the temperature detected by a temperature detector provided in each.

The determination procedure by the light intensity determination unit 43a as described above will be described in detail in the image forming apparatus control method in each of the subsequent embodiments.

-Correction processing section 43b-
The correction processing unit 43b irradiates light from the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 when the light intensity determination unit 43a determines that the decrease in light intensity is within the allowable range. Correct the drive voltage for

-Drive control section 43c-
The drive control unit 43c controls the medium supply unit 10, the image forming unit 20, the medium discharge unit 30, and controls the driving of the display section 42 in the control device 40. The control procedure by the drive control unit 43c will be described in detail in the image forming apparatus control method in each embodiment below.

<How to control the image forming apparatus>
FIG. 7 is a flowchart showing a method for controlling the image forming apparatus according to the first embodiment. The control method for the image forming apparatus shown in this flowchart is a control method carried out in the control section 43 of the control device 40 of the image forming apparatus 1 described using FIGS. This is a procedure executed based on a control program. Hereinafter, a method for controlling the image forming apparatus 1 will be explained along the flowchart of FIG. 7 and with reference to FIGS. 1 to 6 and other figures as necessary.

[Step S100]
In step S100, the drive control unit 43c determines whether it is time to start measuring the light intensity of the curing light irradiation device 25 or the light irradiation device 26a of the image reading device 26. When the timing to start the measurement process has been reached, the drive control unit 43c determines that it is the timing to start the measurement process (YES) and proceeds to the next step S101.

Note that the timing for starting the measurement process is set in advance by, for example, an operation from the operation unit 41 or an input from another external device. This timing is typically set before the start of the job, or every time the curing light irradiation device 25 or the light irradiation device 26a of the image reading device 26 reaches a position facing the photodetector 100. The timing may be set.

[Step S101]
In step S101, the drive control unit 43c performs a process of measuring the light intensity of the irradiated light from the light emitting element. Here, FIG. 8 is a diagram (part 1) illustrating a method of controlling the image forming apparatus 1 according to the first embodiment. In this case, the drive control unit 43c rotates the conveyance drum 21 to detect the light detection unit 100 housed in the recess 21b of the conveyance drum 21, which is one of the light irradiation devices, and here, as an example. It is moved to a position facing the curing light irradiation device 25.

Note that if the timing to start the measurement process is set to the timing every time the curing light irradiation device 25 or the light irradiation device 26a of the image reading device 26 reaches a position facing the photodetector 100, this photodetector There is no need to perform the operation of moving 100.

In this state, that is, with the photodetector 100 facing the curing light irradiation device 25, the drive control unit 43c drives the curing light irradiation device 25 with a predetermined drive voltage, and irradiates the curing light irradiation device 25 with irradiation light. let Then, the irradiated light that has passed through each aperture hole 101a provided in the light shielding member 101 of the photodetector 100 is received by the photodetector 102, and the intensity of the light is detected.

[Step S102]
In step S102, the light intensity determination unit 43a determines whether the light intensity of the irradiation light measured by each light receiving element 102a is greater than or equal to a threshold value preset for the curing light irradiation device 25. . At this time, the light intensity determination unit 43a selects a threshold value corresponding to the temperature of the curing light irradiation device 25 obtained by a temperature detector provided in the curing light irradiation device 25. This suppresses the influence of wavelength fluctuations of the irradiated light due to temperature fluctuations of the curing light irradiation device 25 on the light intensity. This determination is then made by comparing the light intensity of the irradiation light measured by each light receiving element 102a with the selected threshold value.

Then, when the light intensity of the irradiation light detected by all the light receiving elements 102a is greater than or equal to the threshold value, the light intensity determination unit 43a determines that the light intensity is greater than or equal to the threshold value (YES), and proceeds to step S106. On the other hand, if the measured light intensity of the irradiated light in one of the plurality of light receiving elements 102a is not equal to or greater than the threshold value, it is determined that the light intensity is not equal to or greater than the threshold value (NO), and the process proceeds to step S103.

[Step S103]
In step S103, the light intensity determination unit 43a determines whether the measured value of the light intensity, which is determined not to be equal to or greater than the threshold value, is within the permissible range of reduction in light intensity set in advance for the curing light irradiation device 25. make such judgments. At this time, the light intensity determination unit 43a selects a value within the allowable range corresponding to the temperature of the curing light irradiation device 25 obtained by a temperature detector provided in the curing light irradiation device 25. This suppresses the influence of wavelength fluctuations of the irradiated light due to temperature fluctuations of the curing light irradiation device 25 on the light intensity. This determination is then made by comparing the light intensity of the irradiation light measured by each light receiving element 102a with the value of the selected tolerance range.

Then, when the light intensity of the irradiated light measured by all the light receiving elements 102a determined not to exceed the threshold value is within the permissible range, the light intensity determination unit 43a determines that the decrease in the light intensity is within the permissible range. It is determined that there is (YES) and the process advances to step S104. On the other hand, if even one of the light-receiving elements 102a that is determined not to exceed the threshold value has a decrease in light intensity that is not within the allowable range, it is determined that the decrease in light intensity is not within the allowable range (NO). The process then proceeds to step S105.

[Step S104]
In step S104, the correction processing unit 43b corrects the drive voltage of the curing light irradiation device 25 to a value higher than the drive voltage when the light intensity measurement process is performed in step S101. In this case, the correction processing unit 43b may select, as the correction value, a drive voltage held in advance corresponding to each measured value of light intensity. In addition, if it is possible to control the drive of the curing light irradiation device 25 for each portion corresponding to each light receiving element 102a, curing of the portion corresponding to the light receiving element 102a whose light intensity is determined not to be equal to or higher than the threshold value is possible. The driving voltage of the light irradiation device 25 may be corrected. After that, the process advances to step S106.

[Step S105]
In step S105, the drive control unit 43c causes the display unit 42 to issue a notification urging replacement of the curing light irradiation device 25, which is one of the light irradiation devices, or Notification of the time to replace the curing light irradiation device 25 is performed. After that, the process advances to step S106.

[Step S106]
In step S106, it is determined whether all measurements have been completed, and if it is determined that they have been completed (YES), the process is terminated. On the other hand, if it is determined that the process has not ended (NO), the process returns to step S101.

Hereinafter, similar measurement processing will be performed for another light irradiation device of the curing light irradiation device 25, and here, as an example, the light irradiation device 26a of the image reading device 26.

FIG. 9 is a diagram (part 2) illustrating the method of controlling the image forming apparatus according to the first embodiment. As shown in this figure, in the next step S101, the drive control unit 43c rotates the conveyance drum 21 so that the photodetection unit 100 housed in the recess 21b of the conveyance drum 21 faces the image reading device 26. let Thereafter, the above-described procedure is similarly performed on the light irradiation device 26a of the image reading device 26.

<Effects of the first embodiment>
According to the first embodiment described above, the irradiation light from the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 is attenuated by the aperture hole 101a provided in the light shielding member 101, and The light is incident on the light receiving element 102a. Therefore, the light intensity of the irradiated light can be detected with high accuracy without the amount of light received by the light receiving element 102a becoming saturated. Moreover, since the light receiving element 102a is not covered with a filter, the amount of light received by the light receiving element 102a is not further reduced due to dirt attached to the filter. Therefore, the light intensity of the irradiation light emitted from the light irradiation device can be continuously detected with high precision, so that image formation with stable accuracy is possible.

<<Modification of the first embodiment>>
Next, a modification of the first embodiment will be described. Prior to explaining this modification, the characteristics of the light receiving element 102a provided in the photodetector 102 will be explained. FIG. 10 is a graph illustrating the light-receiving sensitivity characteristics of the light-receiving element 102a provided in the photodetector 102, with the horizontal axis representing the wavelength [λ] and the vertical axis representing the light-receiving sensitivity [S]. As shown in this graph, the light receiving element 102a has a characteristic that the light receiving sensitivity [S] is low in the short wavelength region, and the light receiving sensitivity [S] is high in the long wavelength region.

Therefore, when the irradiation light emitted from the curing light irradiation device 25 shown in FIG. 2 is ultraviolet light, this irradiation light is difficult to be detected by the light receiving element 102a. On the other hand, since the light irradiation device 26a of the image reading device 26 emits white light and includes light in a long wavelength range, it is easily detected by the light receiving element 102a.

Therefore, in this modification, the arrangement state of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 with respect to the light detection unit 100 during light intensity measurement is changed in accordance with the light receiving sensitivity characteristics of the light receiving element 102a. do. Thereby, the amount of irradiation light reaching the light receiving element 102a of the photodetector 102 is adjusted by the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26.

FIGS. 11 and 12 are configuration diagrams (part 1) and (part 2) illustrating a modification of the first embodiment. These figures show the arrangement of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 with respect to the photodetector 100 during light intensity measurement.

That is, as shown in FIG. 11, when measuring the light intensity of the curing light irradiation device 25, the curing light irradiation device 25 is placed in the normal direction to the aperture hole 101a. Thereby, more of the short wavelength irradiation light H1 such as ultraviolet light irradiated from the curing light irradiation device 25 passes through the aperture hole 101a and reaches the light receiving element 102a of the photodetector 102.

Further, as shown in FIG. 12, when measuring the light intensity of the light irradiation device 26a of the image reading device 26, the light irradiation device 26a is arranged obliquely with respect to the normal direction to the aperture hole 101a. . This reduces the amount of long-wavelength irradiation light H2 such as white light emitted from the light irradiation device 26a that passes through the aperture hole 101a and reaches the light receiving element 102a of the photodetector 102.

<Effects of modified examples>
According to this modification, the amount of irradiation light reaching the light receiving element 102a is adjusted depending on the arrangement state of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26 when measuring the light intensity. be able to. Therefore, even in the case of having a plurality of light irradiation devices that emit irradiation light of different wavelengths, the irradiation light of each wavelength can be received with the amount of light received within an appropriate range according to the light reception characteristics of the light receiving element 102a. It becomes possible to measure the light intensity of irradiated light with high precision.

≪Second embodiment≫
13 and 14 are configuration diagrams (part 1) and (part 2) illustrating the image forming apparatus 2 according to the second embodiment. The image forming apparatus 2 of the second embodiment shown in these figures differs from the image forming apparatus 1 of the first embodiment in that the photodetector 200 includes a moving mechanism 201 for moving the photodetector 102. It's somewhere. The other configurations are the same as in the first embodiment. Therefore, the configuration of the moving mechanism 201 for moving the photodetector 102 will be described below.

That is, the moving mechanism 201 is attached to the photodetector 102 and freely moves the photodetector 102 between a first detection position [θ1] and a second detection position [θ2] that provide different detection angles. . Here, the detection angle is the arrangement angle of the photodetector 102 with the aperture hole 101a as the center. However, at the first detection position [θ1] and the second detection position [θ2] having different detection angles, the photodetector 102 is arranged with the light-receiving surface of the light-receiving element 102a facing the aperture hole 101a. do.

The first detection position [θ1] and the second detection position [θ2] where the photodetector 102 is arranged are both located at the aperture hole 101a when the photodetector 100 is viewed from the normal direction to the light shielding member 101. It is a position that does not overlap with the aperture hole 101a and is shifted from the aperture hole 101a, for example, in the rotational direction x1 of the conveyance drum 21. Moreover, these first detection position [θ1] and second detection position [θ2] are the irradiation light H1, which is diffracted by passing through another aperture hole 101a arranged close to the corresponding aperture hole 101a. Let H2 be a position close to the light shielding member 101 to such an extent that the photodetector 102 does not receive light.

The second detection position [θ2] is further away from the normal to the aperture hole 101a than the first detection position [θ1]. As a result, compared to the photodetector 102 placed at the first detection position [θ1], the photodetector 102 placed at the second detection position [θ2] has a light that passes through the aperture hole 101a of the light shielding member 101. The structure is such that it is difficult for light to reach.

In this case, as shown in FIG. 13, when measuring the light intensity of the irradiation light H1 from the curing light irradiation device 25 that irradiates light with a shorter wavelength, the photodetector 102 is moved to the first detection position [ θ1] and measure the light intensity. Further, as shown in FIG. 14, when measuring the light intensity of the irradiated light H2 from the light irradiation device 26a for the image reading device 26 that irradiates white light including light on the long wavelength side, the photodetector 102 is placed at the second detection position [θ2] to measure the light intensity.

<Effects of the second embodiment>
According to the configuration of the second embodiment described above, since the arrangement state of the photodetector 102 can be changed, when measuring the light intensity of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26, In this case, the amounts of the irradiation lights H1 and H2 reaching the light receiving element 102a can be adjusted. Therefore, as in the case of the modified example, even if there is a plurality of light irradiation devices that irradiate the irradiation lights H1 and H2 of different wavelengths, the light can be received in an appropriate range according to the light receiving characteristics of the light receiving element 102a. It becomes possible to receive the irradiation light of each wavelength in the same amount and measure the light intensity of the irradiation lights H1 and H2 with high precision.

≪Third embodiment≫
15 and 16 are configuration diagrams (Part 1) and (Part 2) illustrating the image forming apparatus 3 according to the third embodiment. The image forming apparatus 3 of the third embodiment shown in these figures differs from the image forming apparatus 1 of the first embodiment in that the photodetector 300 includes two photodetectors 102 and 103. . The other configurations are the same as in the first embodiment.

These photodetectors 102 and 103 are arranged at a first detection position [θ1] and a second detection position [θ2]. The first detection position [θ1] and the second detection position [θ2] are the same positions as the first detection position [θ1] and the second detection position [θ2] described in the second embodiment.

These photodetectors 102 and 103 have the same configuration as the photodetector 102 described in the first embodiment, and each has light receiving elements 102a and 103a. These light receiving elements 102a and 103a may have the same light receiving sensitivity characteristics, or may have different light receiving sensitivity characteristics.

FIG. 17 is a graph illustrating the light receiving sensitivity characteristics of the photodetectors 102 and 103 included in the image forming apparatus 3 according to the third embodiment. As shown in this figure, the light receiving element 103a of the photodetector 103 placed at the first detection position [θ1] is the same as the light receiving element 102a of the photodetector 102 placed at the second detection position [θ2]. In comparison, it is assumed that the light receiving sensitivity [S] is high in a shorter wavelength region.

In any case, as shown in FIG. 15, if the light intensity of the irradiation light H1 from the curing light irradiation device 25 that irradiates light with a shorter wavelength is to be measured, the first detection position [ The light intensity is measured by the light receiving element 103a of the photodetector 103 located at θ1]. Further, as shown in FIG. 16, when measuring the light intensity of the irradiated light H2 from the light irradiation device 26a of the image reading device 26 that irradiates white light including light on the long wavelength side, the second detection position The light intensity is measured by the light receiving element 102a of the photodetector 102 placed at [θ2].

<Effects of the third embodiment>
According to the configuration of the third embodiment described above, by arranging the light receiving elements 102a and 103a at different positions, when measuring the light intensity of the curing light irradiation device 25 and the light irradiation device 26a of the image reading device 26, , the amount of irradiation light reaching each light receiving element 102a, 103a can be adjusted. For this reason, even if there is a plurality of light irradiation devices that emit irradiation lights H1 and H2 of different wavelengths, the light receiving elements 102a and 103a are located at positions where they can receive the irradiation lights H1 and H2 with an appropriate amount of light reception. By selecting, it becomes possible to measure the light intensity of the irradiation lights H1 and H2 with high precision.

1, 2, 3... Image forming device 20... Image forming section 21... Conveyance drum (medium conveyance section)
21a...Conveyance surface 21b...Concave portion 24...Head unit (ink supply device)
25...Curing light irradiation device (light irradiation device)
26... Image reading device 26a... Light irradiation device 43... Control section 101... Light shielding member 102... Photodetector 100... Photo detection section 101a... Aperture hole 102a... Light receiving element 42... Display section (notification section)
P...Recording medium H, H1, H2...Irradiation light x...Transportation direction x1...Rotation direction (transportation direction)

Claims (16)

an image forming unit that forms an image on a recording medium;
a light irradiation device that irradiates the recording medium with light;
a light detection unit having a light shielding member that allows the irradiation light emitted from the light irradiation device to pass through, and a photodetector that detects the light intensity of the irradiation light that has been attenuated by the light shielding member;
comprising a control unit that controls driving of the image forming unit and the light irradiation device,
The light shielding member has at least one aperture hole,
The photodetector detects the light intensity of the irradiation light that is irradiated from the light irradiation device and passes through the aperture hole,
The aperture hole is formed to have a diameter that diffracts the irradiated light,
The photodetector is arranged at a position that is off the normal line of the light shielding member at the position where the aperture hole is formed.
Image forming device. The image forming unit includes an ink supply device that supplies ink to the recording medium,
The image forming apparatus according to claim 1 , wherein the light irradiation device includes a curing light irradiation device that irradiates the recording medium with light for curing ink supplied to the recording medium. The image forming apparatus according to claim 1 , wherein the light irradiation device includes a white light irradiation device provided in an image reading device for reading an image formed on the recording medium. The control unit detects the light intensity of the irradiated light from the light irradiation device with the photodetector while the light irradiation device is placed at a predetermined position with respect to the aperture hole . The image forming apparatus according to any one of the items. The light irradiation device includes a plurality of light irradiation devices that irradiate light of different wavelengths,
The control unit individually detects the light intensity of the irradiated light from each of the light irradiation devices with the photodetector, with each of the plurality of light irradiation devices arranged at predetermined positions with respect to the aperture hole. The image forming apparatus according to any one of claims 1 to 4 . The photodetector is configured to be movable to positions with different detection angles,
The image forming apparatus according to claim 5 , wherein the control section controls the position of the light detection section in accordance with each of the light irradiation devices. A plurality of the photodetectors are arranged at positions with different detection angles,
The image forming apparatus according to claim 5 , wherein the control unit individually detects the irradiation light from each of the light irradiation devices with each of the photodetectors arranged at positions with different detection angles. The image forming apparatus according to claim 7 , wherein the plurality of photodetectors have light receiving elements having different light receiving characteristics. The image forming apparatus according to any one of claims 1 to 8 , wherein the control section controls driving of the light irradiation device based on the intensity of the irradiation light received by the photodetector. comprising a notification unit that performs notification based on instructions from the control unit,
The control unit causes the notification unit to issue a notification urging replacement of the light irradiation device when the intensity of the irradiation light received by the photodetector falls below a threshold value. The image forming apparatus according to any one of the above. The light irradiation device includes a temperature detector,
The image forming apparatus according to claim 10 , wherein the control unit changes the threshold value based on the temperature of the light irradiation device detected by the temperature detector. The image forming unit and the light irradiation device include a medium transport unit that transports the recording medium,
Any one of claims 1 to 11 , wherein the photodetector is arranged to face the light irradiation device across a transport width direction perpendicular to the transport direction of the recording medium by the medium transport unit. The image forming apparatus described in . The light shielding member has a plurality of aperture holes arranged across the conveyance width direction,
The photodetector includes a plurality of light receiving elements arranged corresponding to each of the aperture holes,
The image forming apparatus according to claim 12 , wherein each of the light receiving elements individually receives each of the irradiation lights that have passed through each of the aperture holes and detects the light intensity. The image forming unit and the light irradiation device include a medium transport unit that transports the recording medium,
The medium transport section has a recess on the transport surface of the recording medium,
The image forming apparatus according to any one of claims 1 to 13 , wherein the light detection section is housed in the recess. an image forming section that forms an image on a recording medium, a light irradiation device that irradiates light onto the recording medium, a light shielding member that allows the irradiation light irradiated from the light irradiation device to pass, and the light attenuated by the light shielding member. The light-blocking member includes a photodetector having a photodetector that detects the light intensity of the irradiation light, and a control unit that controls driving of the image forming unit and the light irradiation device, and the light shielding member has a diameter that diffracts the irradiation light. The photodetector has at least one aperture hole formed with A control method for an image forming apparatus that detects the light intensity of the irradiation light that has passed through an aperture hole, the method comprising:
A method for controlling an image forming apparatus, wherein the control unit detects the light intensity of the irradiated light from the light irradiation device with the photodetector while the light irradiation device is placed at a predetermined position with respect to the aperture hole. . an image forming section that forms an image on a recording medium, a light irradiation device that irradiates light onto the recording medium, a light shielding member that allows the irradiation light irradiated from the light irradiation device to pass, and the light attenuated by the light shielding member. The light-blocking member includes a photodetector having a photodetector that detects the light intensity of the irradiation light, and a control unit that controls driving of the image forming unit and the light irradiation device, and the light shielding member has a diameter that diffracts the irradiation light. The photodetector has at least one aperture hole formed with A control program for an image forming apparatus that detects the light intensity of the irradiation light that has passed through the aperture hole,
causing the control unit to place the light irradiation device at a predetermined position with respect to the aperture hole, and causing the photodetector to detect the light intensity of the irradiation light from the light irradiation device;
A control program for an image forming device.

Images