Laser printing device

Abstract

The output of the UV laser light is stabilized by simultaneously ensuring stable operation of the air pump and keeping the inside of the wavelength conversion section clean. [Solution] The laser printing device L comprises a wavelength conversion unit 3 that generates UV laser light, a sealed unit 4 that constitutes a sealed chamber S1 of the wavelength conversion unit 3, and an air pump 8. The air pump 8 includes a diaphragm 81, a housing 82 that partitions the pump chamber S2, a pump drive unit 83 that circulates air between the pump chamber S2 and the sealed chamber S1 through first and second communication ports 82a and 82b of the housing 82 by applying a driving force to the diaphragm 81, a valve seat 84 arranged around the first and second communication ports 82a and 82b, and a check valve 85 that makes contact with or separates from the valve seat 84 in accordance with the volume change of the pump chamber S2. The portion of the valve seat 84 that makes contact with or separates from the check valve 85 in accordance with the volume change of the pump chamber S2 is covered with a metal film 88 that constitutes an uneven shape 89.

Description

Technical Field

[0001] The present disclosure relates to a laser printing device.

Background Art

[0002] For example, Patent Document 1 discloses a laser processing device as a laser printing device. Specifically, the laser processing device disclosed in Patent Document 1 includes a Q-switch, first and second wavelength conversion elements, a Q-switch housing portion in which the Q-switch is housed, and a wavelength conversion portion in which the first and second wavelength conversion elements are housed, and is configured to generate and output UV laser light.

[0003] According to Patent Document 1, the Q-switch is disposed outside the wavelength conversion portion. By arranging it in this way, the generation of impurities inside the wavelength conversion portion derived from the Q-switch can be suppressed. Suppressing the generation of impurities contributes to suppressing the reduction in the output of UV laser light.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] The inventors of the present application considered connecting a diaphragm-type air pump to the wavelength conversion portion as disclosed in Patent Document 1. In this case, by circulating air by the air pump, impurities can be actively removed from the wavelength conversion portion.

[0006] In this context, when using an air pump, it is considered necessary to improve the sealing between the check valve that constitutes the air pump and the valve seat on which the check valve sits in order to ensure the pump pressure. To improve the sealing between the two components, the valve seat surface of the valve seat (the surface on which the check valve sits) must be smooth.

[0007] On the other hand, as described in Patent Document 1, the wavelength conversion unit for a laser printing device is required to be as clean as possible to prevent the generation of impurities. Therefore, the flow path connecting the wavelength conversion unit and the air pump, as well as the components of the air pump, are used in a degreased and clean state.

[0008] The inventors of this invention noticed that when an air pump is operated in such a clean environment, if the valve seat surface is too smooth, the check valve and the valve seat surface may stick together while remaining sealed, which could interfere with the operation of the air pump.

[0009] This disclosure has been made in view of the above, and its purpose is to achieve both stabilization of the operation of the air pump and keeping the inside of the wavelength conversion unit clean, and ultimately to stabilize the output of the UV laser light. [Means for solving the problem]

[0010] A first aspect of this disclosure relates to a laser printing apparatus. This laser printing apparatus includes: an excitation light generation unit that generates excitation light; a basic laser generation unit that generates basic laser light based on the excitation light generated by the excitation light generation unit; a wavelength conversion unit that generates UV laser light based on the basic laser light generated by the basic laser generation unit; a sealed chamber that hermetically seals the wavelength conversion unit and has a transmissive window through which the UV laser light generated by the wavelength conversion unit is emitted to the outside of the sealed chamber; a laser light scanning unit that performs two-dimensional scanning of the UV laser light emitted from the transmissive window; and an air pump that communicates with the inside of the sealed chamber and circulates air between the air pump and the inside of the sealed chamber.

[0011] Furthermore, according to the first embodiment, the air pump comprises a diaphragm that deforms in response to the application of a driving force, a pump chamber whose volume changes in response to the deformation of the diaphragm, a housing that partitions the pump chamber and the sealed chamber by a plurality of communication ports that connect the insides of the pump chamber and the sealed chamber, respectively, by applying a driving force to the diaphragm, a pump drive unit that circulates air between the insides of the pump chamber and the sealed chamber through the plurality of communication ports, a valve seat provided in the housing and arranged around each of the plurality of communication ports, and a check valve attached to each of the valve seats that makes contact with or separates from the valve seat in response to the change in volume of the pump chamber due to the deformation of the diaphragm, wherein the portion of the valve seat that makes contact with or separates from the check valve in response to the change in volume of the pump chamber is covered with a metal film that forms an uneven shape on the surface of the valve seat.

[0012] According to the first embodiment described above, a portion of the valve seat is covered with a metal film. The metal film forms an uneven surface, which suppresses adhesion between the valve seat and the check valve. This allows for both stabilization of the air pump's operation and keeping the inside of the wavelength conversion section clean, and consequently, stabilization of the UV laser light output.

[0013] Furthermore, covering a portion of the valve seat with a metal film, as in the first embodiment described above, offers superior control over its surface condition compared to a configuration in which the entire valve seat or check valve is made of metal. Therefore, the surface condition of the metal film (for example, the degree of unevenness of the metal film) can be kept within an appropriate range to achieve both the suppression of adhesion between the valve seat and check valve and the sealing performance.

[0014] Furthermore, according to a second aspect of this disclosure, the laser printing apparatus may be provided with a filter located in the middle of a flow path connecting the pump chamber and the sealed chamber, which removes impurities contained in the air flowing through the flow path.

[0015] According to the second embodiment, by placing a filter in the middle of the flow path, impurities can be effectively removed from the wavelength conversion section without excessively increasing the pump pressure of the air pump. Since there is a margin of safety in the sealing between the valve seat and the check valve, adhesion between the two components can be suppressed.

[0016] Furthermore, according to a third aspect of this disclosure, the check valve may be made of a flexible member.

[0017] When a check valve is flexible, adhesion between the valve seat and the check valve becomes an even greater concern. This disclosure is particularly useful in such circumstances.

[0018] Furthermore, according to a fourth aspect of this disclosure, the housing may be made of resin, and at least a portion of the flow path connecting the pump chamber and the communication port may be covered with a metal film.

[0019] Generally, resin housings are thought to be less prone to adhesion with check valves than metal housings. However, resin housings are undesirable because they allow organic gases to permeate them.

[0020] In contrast, as in the fourth embodiment described above, the permeation of organic gases as described above can be suppressed by covering the valve seat and the flow path with a metal film.

[0021] Furthermore, according to a fifth aspect of this disclosure, the valve seat may be formed integrally with the housing, and the housing may be covered with a metal film.

[0022] Further, according to the sixth aspect of the present disclosure, the plurality of communication ports include a first communication port for sending air from the sealed chamber to the pump chamber and a second communication port for sending air from the pump chamber to the sealed chamber. The valve seat has a first valve seat disposed around the first communication port and a second valve seat disposed around the second communication port. The check valve may be configured such that a portion that contacts or separates from the first valve seat and a portion that contacts or separates from the second valve seat are integrally formed by a single member.

[0023] The sixth aspect of the present disclosure relates to a laser marking device. This laser marking device includes an excitation light generation unit that generates excitation light, a basic laser generation unit that generates basic laser light based on the excitation light generated by the excitation light generation unit, a wavelength conversion unit that generates UV laser light based on the basic laser light generated by the basic laser generation unit, a sealed unit that forms a sealed chamber that hermetically seals the wavelength conversion unit and has a transmission window that emits the UV laser light generated by the wavelength conversion unit to the outside of the sealed chamber, a laser light scanning unit that two-dimensionally scans the UV laser light emitted from the transmission window, and an air pump that communicates with the inside of the sealed chamber and circulates air between the inside of the sealed chamber.

[0024] And according to the seventh aspect, the air pump includes a diaphragm that deforms in response to the application of a driving force, a pump chamber whose volume changes in response to the deformation of the diaphragm, a housing that partitions a plurality of communication ports that communicate the interiors of the pump chamber and the sealed chamber, a pump driving unit that circulates air between the interiors of the pump chamber and the sealed chamber through the plurality of communication ports by applying a driving force to the diaphragm, a valve seat provided on the housing and disposed around each of the plurality of communication ports, and a check valve attached to each of the valve seats and that contacts or separates from the valve seat in response to the volume change of the pump chamber due to the deformation of the diaphragm. The portion of the check valve that contacts or separates from the valve seat in response to the volume change of the pump chamber is covered by a metal film that forms a concavo-convex shape on the surface of the check valve.

[0025] According to the seventh aspect, a part of the check valve is coated with a metal film. By configuring the metal film to have an uneven shape, adhesion between the valve seat and the check valve can be suppressed. It is possible to achieve both the stabilization of the operation of the air pump and the maintenance of a clean environment inside the wavelength conversion unit, and ultimately, the output of the UV laser light can be stabilized.

[0026] In addition, coating a part of the check valve with a metal film as in the seventh aspect is superior in terms of controllability of its surface state compared to a configuration where the entire valve seat or check valve is made of metal. Therefore, the surface state of the metal film (for example, the degree of unevenness of the metal film) can be kept within an appropriate range so that both suppression of adhesion between the valve seat and the check valve and sealing performance can be achieved.

Advantages of the Invention

[0027] As described above, according to the present disclosure, it is possible to achieve both the stabilization of the operation of the air pump and the maintenance of a clean environment inside the wavelength conversion unit, and ultimately, the output of the UV laser light can be stabilized.

Brief Description of the Drawings

[0028] [Figure 1] FIG. 1 is a diagram illustrating the overall configuration of a laser marking system. [Figure 2] FIG. 2 is a diagram illustrating the schematic configuration of a laser marking device. [Figure 3] FIG. 3 is a diagram illustrating the schematic configuration of a printing head. [Figure 4] FIG. 4 is a perspective view illustrating the appearance of a printing head. <​​​​​​​​​​​​​​ [Figure 10] Figure 10 is a plan view illustrating the configuration of a check valve. [Figure 11] Figure 11 is a magnified partial view illustrating the structure of a metal film. [Figure 12] Figure 12 is a magnified partial view illustrating the structure of a metal film. [Figure 13] Figure 13 is a corresponding diagram to Figure 11, showing a modified example of the metal film. [Figure 14] Figure 14 is a diagram illustrating the operation of an air pump. [Figure 15] Figure 15 is a magnified section showing further modifications of the metal film. [Modes for carrying out the invention]

[0029] The embodiments of this disclosure will be described below with reference to the drawings. Note that the following description is illustrative.

[0030] In other words, although this specification describes a laser printing apparatus, this disclosure can be applied to laser application equipment in general, such as "laser markers" and "laser processing equipment," which are capable of performing printing using laser light (laser printing), regardless of the name "laser printing apparatus."

[0031] In the following descriptions, the term "printing" may be replaced with "laser printing," "marking," "printing process," or "processing."

[0032] <1. Overall Structure> Figure 1 is a diagram illustrating the overall configuration of the laser printing system S, and Figure 2 is a diagram illustrating the schematic configuration of the laser printing device L in the laser printing system S.

[0033] As illustrated in Figure 1, the laser printing system S comprises a laser printing device L and an external device 400 connected to the laser printing device L.

[0034] Of these, the laser printing device L shown in Figures 1 and 2 is configured to print a predetermined printing pattern Pm within the printing area R1 by controlling the laser light generation unit 2 and the laser light scanning unit 6, which will be described later.

[0035] The printing area R1 referred to here is the area set on the surface of the workpiece W, which is the object to be printed on, as shown in Figure 1. The printing area R1 may be set to include the entire workpiece W, or it may be set to include only a part of the workpiece W.

[0036] The laser printing device L prints by irradiating the workpiece W with laser light generated by its print head 1 and simultaneously performing a three-dimensional scan on the surface of the workpiece W. Here, "three-dimensional scanning" refers to a concept that combines a two-dimensional operation (so-called "two-dimensional scanning") of scanning the laser beam's irradiation position on the surface of the workpiece W with a one-dimensional operation of adjusting the laser beam's focal position. Three-dimensional scanning is not mandatory; the laser printing device L only needs to be capable of at least two-dimensional scanning.

[0037] In particular, the laser printing apparatus L according to this embodiment can emit laser light included in the ultraviolet (UV) wavelength range, for example, laser light having a wavelength around 355 nm, as laser light for printing on the workpiece W. In the following description, the laser light for printing on the workpiece W may be referred to as "UV laser light" or "printing laser light" to distinguish it from other laser light.

[0038] As shown in Figures 1 and 2, the laser printing apparatus L according to this embodiment comprises a print head 1, a print controller 100, a connection cable 200, and a setting device 300.

[0039] The print head 1 is controlled by the print controller 100 to emit UV laser light toward the print area R1. The print head 1 can perform three-dimensional scanning of the UV laser light within the print area R1.

[0040] The print controller 100 is configured as a controller for controlling the print head 1. In addition, the print controller 100 can store settings related to the print pattern Pm, for example, various conditions (printing conditions) for printing a desired print pattern Pm, and can also correct those printing conditions. In this embodiment, the print controller 100 is a separate unit from the print head 1.

[0041] The connection cable 200 electrically connects the print head 1 and the print controller 100. This connection cable 200 is, for example, made up of electrical wiring capable of sending and receiving electrical signals between the print head 1 and the print controller 100.

[0042] Furthermore, if the excitation light generation unit 110 is laid out within the printing controller 100 as described later, the connection cable 200 may be configured by combining the electrical wiring with an optical fiber cable.

[0043] More generally, one of the print head 1 and the print controller 100 can be integrated into the other. In this case, unnecessary wiring can be omitted as appropriate.

[0044] The setting device 300 sets various printing conditions and functions as a terminal for displaying information related to laser printing to the user. This setting device 300 has, for example, a central processing unit (CPU) and memory, and is connected to the print controller 100 so as to be able to send and receive electrical signals via wired or wireless means.

[0045] In this embodiment, the setting device 300 is configured as a personal computer such as a desktop computer or a laptop computer, but this disclosure is not limited to such configurations.

[0046] The setting device 300 may be configured as a dedicated terminal that can be connected to the laser printing device L, such as a touch panel console. Alternatively, the setting device 300 can be integrated into the printing controller 100, for example.

[0047] External devices 400 are connected to the print controller 100 as needed. In the example shown in Figure 1, the external devices 400 consist of a transport speed sensor 401 and a programmable logic controller (PLC) 402.

[0048] The transport speed sensor 401 is configured, for example, by a rotary encoder and can detect the transport speed of the workpiece W. The transport speed sensor 401 outputs a signal (detection signal) indicating the detection result to the print controller 100. The print controller 100 controls the two-dimensional scanning of the UV laser beam, etc., based on the detection signal input from the transport speed sensor 401.

[0049] The PLC402 is configured, for example, with a microprocessor and can input trigger signals to the print controller 100. The PLC402 is used to control the laser printing system S according to a predetermined sequence.

[0050] In addition to the equipment and devices described above, the laser printing device L can be connected wirelessly or via wired connections to devices for operation and control, computers for various other processing tasks, storage devices, peripheral devices, etc.

[0051] The following will describe, in order, the hardware configuration of the setting device 300, the print controller 100, and the print head 1, the configuration of the data settings transmitted from the setting device 300 to the print controller 100, and the configuration of the control of the print head 1 by the print controller 100 based on those data settings.

[0052] <2. Setting device 300> As shown in Figures 1 and 2, the setting device 300 according to this embodiment includes a display unit 301, an operation unit 302, a storage unit 303, and a processing unit 304. The setting device 300 is a terminal operated by the user and can also be called an "operation terminal."

[0053] (Display section 301) The display unit 301 displays information to the user. More specifically, the display unit 301 displays information to the user via its display screen. This display unit 301 can be configured as a liquid crystal display or an organic EL panel.

[0054] Furthermore, the display screen of the display unit 301 also functions as a screen for receiving user input via the operation unit 302 (hereinafter referred to as "user input"). Specifically, the display unit 301 according to this embodiment displays a setting surface R2 corresponding to the printing area R1. A user interface for receiving input of the printing pattern Pm is arranged on this setting surface R2.

[0055] It is not mandatory for the setting device 300 to include a display unit 301. The display unit 301 may be provided by the print controller 100 or the print head 1. For example, if the setting device 300 is incorporated into the print controller 100 or a touch panel console is used, the display screen provided on the print controller 100 or the console can be used as the display unit.

[0056] (Operation unit 302) The operation unit 302 receives user input and inputs an electrical signal corresponding to that user input to the CPU or the like. The operation unit 302 can be composed of a keyboard and a pointing device. Pointing devices include a mouse, joystick, and the like.

[0057] It is not mandatory for the setting device 300 to include an operation unit 302. The operation unit 302 may be provided by the print controller 100 or the print head 1. For example, if the setting device 300 is incorporated into the print controller 100 or a touch panel console is used, switches, buttons, etc. provided on the print controller 100 or console can be used as the scanning unit.

[0058] (Storage unit 303) The memory unit 303 stores various types of information. The memory unit 303 is composed of volatile memory such as random access memory (RAM) and read-only memory (ROM), and non-volatile memory such as a hard disk drive (HDD) and solid-state drive (SSD). The memory unit 303 temporarily or continuously stores information that is input by the user via the operation unit 302, pre-set by the manufacturer, or sent and received from the print controller 100 each time.

[0059] (Processing Unit 304) The processing unit 304 performs various processes based on the contents stored in the storage unit 303. The processing unit 304 is composed of one or more processors (e.g., CPUs).

[0060] The processing unit 304 executes processing corresponding to each function in order to realize multiple different functions. For example, the processing unit 304 can set a print pattern Pm to be printed on the workpiece W and the print conditions for printing that print pattern Pm, based on user input. This function is realized, for example, by the print setting unit 304a of the processing unit 304.

[0061] The print pattern Pm and print conditions set by the processing unit 304 are stored in the storage unit 303 of the setting device 300, or output to the print controller 100 and stored in the storage unit 101 of the print controller 100. Hereinafter, the combination of print pattern Pm and print conditions will be referred to as the "print setting". If necessary, the storage unit 303 of the setting device 300 may store the print setting.

[0062] <3. Print Controller 100> As shown in Figure 2, the print controller 100 includes a storage unit 101 that stores print settings transmitted from the setting device 300, a head control unit 102 that controls the print head 1 based on the print settings, an excitation light generation unit 110 that generates laser excitation light (excitation light), and a trigger signal receiving unit 120. Note that it is not essential for the print controller 100 to have the excitation light generation unit 110; the print head 1 may also have the excitation light generation unit 110. Similarly, the trigger signal receiving unit 120 may be provided in the setting device 300.

[0063] (Storage unit 101) The memory unit 101 stores the print settings determined by the setting device 300 and is configured to output the stored contents to the head control unit 102 as needed.

[0064] Specifically, the storage unit 101 is composed of volatile memory such as RAM and ROM, and non-volatile memory such as HDD and SSD, and can temporarily or continuously store information indicating print settings. If the setting device 300 is incorporated into the print controller 100, the storage unit 303 of the setting device 300 may also serve as the storage unit 101.

[0065] (Head control unit 102) The head control unit 102 controls the laser light generation unit 2 and the laser light scanning unit 6 to perform a printing process that forms a predetermined printing pattern Pm within the printing area R1. Specifically, the head control unit 102 controls the excitation light generation unit 110, the laser light generation unit 2, the laser light scanning unit 6, etc., based on the printing settings stored in the memory unit 101. The printing process by the head control unit 102 results in laser printing (printing operation) by the print head 1 being performed.

[0066] Specifically, the head control unit 102 has a CPU, memory, and input / output bus, and generates control signals based on signals indicating information input via the setting device 300 and signals indicating printing conditions (details described later) read from the storage unit 101. The head control unit 102 controls laser printing on the workpiece W by outputting the generated control signals to each part of the laser printing device L.

[0067] For example, when the head control unit 102 starts laser printing on the workpiece W, it reads the laser power stored in the memory unit 101 and outputs a control signal generated based on that laser power to the excitation light generation unit 110 to control the generation of laser excitation light. Alternatively, instead of controlling the generation of laser excitation light, it can also output a control signal generated based on the laser power stored in the memory unit 101 to the Q switch 24 to control the on / off state of the Q switch 24.

[0068] Furthermore, when actually printing on the workpiece W, the head control unit 102 reads, for example, the printing pattern Pm stored in the memory unit 101, and outputs a control signal generated based on that printing pattern Pm to the laser beam scanning unit 6, thereby scanning the UV laser beam in two dimensions. In this way, the head control unit 102 can control the laser beam scanning unit 6 to achieve two-dimensional scanning of the laser beam.

[0069] (Excitation photogeneration unit 110) The excitation light generation unit 110 oscillates laser light according to the drive current and focuses the oscillated laser light to output it as laser excitation light (excitation light). Specifically, the excitation light generation unit 110 according to this embodiment is composed of an excitation light source that oscillates laser light and a focusing unit that focuses the laser. The excitation light source can be composed of, for example, a laser diode (LD). The focusing unit can be composed of, for example, a focusing lens.

[0070] The excitation light generated by the excitation light generation unit 110 is input to the laser light generation unit 2. Although not shown in detail, the excitation light generation unit 110 according to this embodiment is built into the print head 1.

[0071] (Trigger signal receiving unit 120) The trigger signal receiving unit 120 receives a trigger signal input. This trigger signal functions as a trigger for the head control unit 102 to execute the printing process. Specifically, the trigger signal receiving unit 120 in this embodiment is electrically connected to the PLC 402 and receives the trigger signal output from the PLC 402. Upon receiving the trigger signal, the trigger signal receiving unit 120 inputs an electrical signal indicating this to the head control unit 102. The head control unit 102 receives this electrical signal and executes the printing process.

[0072] <4. Print head 1> Figure 3 is a diagram illustrating the schematic configuration of the print head 1. Figure 4 is a perspective view illustrating the external appearance of the print head 1. Figure 5 is a diagram illustrating a further schematic configuration of the print head 1.

[0073] The print head 1 generates laser light (UV laser light) based on excitation light and irradiates the workpiece W with the laser light. The laser light irradiated onto the workpiece W is scanned in three dimensions as described above.

[0074] Specifically, the print head 1 comprises a laser light generation unit 2, a wavelength conversion unit 3, a sealing unit 4, a height-direction scanning unit 5, a laser light scanning unit 6, an air purge unit 7, and a housing 10.

[0075] As shown in Figure 3, the housing 10 houses a laser light generation unit 2, a wavelength conversion unit 3, a sealed unit 4, a height-direction scanning unit 5 having a focus adjustment unit 53, a laser light scanning unit 6, and an air purge unit 7. The sealed unit 4 houses the wavelength conversion unit 3.

[0076] As shown in Figure 5, the bottom surface of the housing 10 is partitioned by a plate-shaped bottom plate 10a. This bottom plate 10a is provided with an emission window 19 for emitting UV laser light from the print head 1 to the outside of the print head 1. The emission window 19 is constructed by fitting a plate-shaped transparent member that can transmit UV laser light into a through-hole that penetrates the bottom plate 10a in the thickness direction.

[0077] Furthermore, as shown in Figure 3, with respect to the propagation direction of the laser light, the height scanning unit 5 and the focus adjustment unit 53 are interposed between the laser light generation unit 2 and the wavelength conversion unit 3 and the laser light scanning unit 6.

[0078] In the following description, the longitudinal direction of the housing 10 in Figure 5 may be simply referred to as the "longitudinal direction," "front-to-back direction," or "X direction," and the short direction of the housing 10 in the same figure may be simply referred to as the "short direction," "left-to-right direction," or "Y direction." Similarly, the height direction of the housing 10 in Figure 5 may be simply referred to as the "height direction," "up-down direction," or "Z direction."

[0079] (Laser light generation unit 2) The laser light generation unit 2 generates fundamental laser light based on the excitation light generated by the excitation light generation unit 110. This laser light generation unit 2 is located outside the sealed unit 4.

[0080] The laser light generation unit 2 according to this embodiment includes, in addition to the first resonant member 21, a first optical member 22, a laser medium 23, and a Q switch 24.

[0081] -Overall Structure- The laser light generation unit 2 is optically coupled to the wavelength conversion unit 3, which is housed in the sealed unit 4. This optical coupling is used to form a resonator between the laser light generation unit 2 and the wavelength conversion unit 3, which is used to resonate the laser light.

[0082] In detail, this resonator is composed of a first resonant member 21 and a Q-switch 24, and a second resonant member 31 of the wavelength conversion unit 3. The first resonant member 21 and the second resonant member 31 are each made of mirrors capable of reflecting laser light, and a resonant optical path L1 is formed between the first resonant member 21 and the second resonant member 31 to resonate the laser light. The laser light forms a standing wave on this resonant optical path L1, connecting the laser light generation unit 2 and the wavelength conversion unit 3.

[0083] In other words, the names "laser light generation unit 2" and "wavelength conversion unit 3" are merely designations given to clarify the function of each unit, and it may be considered that the laser light generation unit 2 and the wavelength conversion unit 3 constitute a single laser oscillator.

[0084] Furthermore, as shown in Figure 4, in this embodiment, a first wavelength conversion element 32 as an SHG and a second wavelength conversion element 33 as a THG are arranged in the middle of the resonant optical path L1, which is composed of a first resonant member 21 and a second resonant member 31. In other words, the laser light generation unit 2 and the wavelength conversion unit 3 according to this embodiment include an intracavity type resonator.

[0085] Furthermore, the configuration of the resonator is not limited to an intracavity type configuration. For example, a so-called extracavity type resonator may be used, in which the first wavelength conversion element 32 and the second wavelength conversion element 33 are arranged outside the optical path L1 of the resonant optical path.

[0086] Below, we will describe, in order, each optical element constituting the laser light generation unit 2, excluding the first resonant member 21.

[0087] -First optical component 22- The first optical element 22 is configured to guide the excitation light generated by the excitation light generation unit 110 to the resonant optical path L1. The first optical element 22 is composed of, for example, a half mirror.

[0088] More specifically, the first optical member 22 transmits the excitation light generated by the excitation light generation unit 110 and guides it to the laser medium 23. The first optical member 22 also bends the laser light, which has passed through the laser medium 23 and reached the wavelength conversion unit 3, and has been reflected back by the second resonant member 31, toward the Q switch 24 and the first resonant member 21. The first optical member 22 is also configured to bend the laser light, which has been reflected back by the first resonant member 21, toward the laser medium 23 again.

[0089] Note that the first optical element 22 is not essential. Depending on the layout of each optical component in the laser light generation unit 2 and the wavelength conversion unit 3, the first optical element 22 may be omitted.

[0090] -Laser medium 23- The laser medium 23 is configured to generate a fundamental wave (fundamental laser light) by performing stimulated emission corresponding to the excitation light. Specifically, the laser medium 23 is a laser medium capable of forming population inversion, and is configured to perform stimulated emission corresponding to the incident laser excitation light when laser excitation light is incident on the medium. The wavelength of the photons emitted by stimulated emission (the so-called fundamental wavelength) increases or decreases depending on the configuration of the laser medium 23, but in this example it is in the infrared region of around 1 μm.

[0091] In this embodiment, a rod-shaped Nd:YVO4 (yttrium vanadite) was used as the laser medium 23. Laser excitation light is incident from one end face of the rod-shaped laser medium 23, and laser light with the fundamental wavelength (so-called fundamental wave) is emitted from the other end face (a so-called unidirectional excitation method by end pumping). In this example, the fundamental wavelength is set to 1064 nm. On the other hand, the wavelength of the laser excitation light is set near the center wavelength of the absorption spectrum of Nd:YVO4 in order to promote stimulated emission. However, this is not limited to this example, and other laser media such as rare earth-doped YAG, YLF, GdVO4, etc. can also be used. Various solid laser media can be used depending on the application of the laser processing apparatus L.

[0092] Furthermore, by combining a wavelength conversion element with the solid laser medium, the wavelength of the output laser light can be converted to any desired wavelength. In this case, unlike in Figure 4, the laser medium 23 may be housed in the wavelength conversion unit 3. Alternatively, a so-called fiber laser may be used, in which a fiber is used as the oscillator instead of bulk as the solid laser medium.

[0093] Furthermore, the print head 1 is not limited to solid-state lasers; it may also utilize gas lasers that use gases such as CO2, helium-neon, argon, or nitrogen as the medium. For example, in the case of a carbon dioxide laser, the laser medium is filled with carbon dioxide (CO2) and contains electrodes, and the laser oscillates by exciting the carbon dioxide based on a printing signal input from the laser control device.

[0094] Furthermore, the laser light generation unit 2 can also utilize a two-directional excitation method, in which excitation light is irradiated from both the front and rear end faces of the solid laser medium, instead of the aforementioned one-directional excitation method, as an excitation method using the solid laser medium.

[0095] -Q Switch 24- The Q-switch 24 is configured to pulse the fundamental wave (fundamental laser light) generated by the laser medium 23. In detail, the Q-switch 24 is positioned on the optical axis of the resonant optical path L1 and is interposed between the laser medium 23 and the first resonant member 21 (specifically, between the first optical member 22 and the first resonant member 21).

[0096] The Q-switch 24 makes it possible to convert continuous oscillation into high-speed repetition pulse oscillation with a high peak power value. In other words, the Q-switch 24 can convert a CW (Continuous Wave) laser into a pulsed laser and output it.

[0097] Furthermore, a Q-switch control circuit that generates an RF signal to be applied to the Q-switch 24 is connected to it. The laser light generation unit 2 amplifies the laser light, which consists of photons stimulated and emitted from the laser medium 23, by multiple reflections between the first resonant member 21 and the second resonant member 31, and outputs the laser light after passing it through the laser light separation unit 34.

[0098] In other words, when the Q-switch 24 is turned on, the laser light incident on the Q-switch 24 is deflected and separated from the resonant optical path L1. In this case, as a result of restricting multiple reflections of the laser light, the generation of population inversion in the laser medium 23 is promoted.

[0099] Then, when the Q-switch 24 is turned on for a predetermined period of time and then switched off, the laser light is amplified by multiple reflections. In this case, a high-power laser light will oscillate in pulses. By periodically switching the Q-switch 24 on and off in this way, the high-speed repetitive pulse oscillation described above can be achieved.

[0100] (Wavelength conversion unit 3) The wavelength conversion unit 3 generates UV laser light based on the fundamental laser light generated by the laser light generation unit 2. As mentioned above, this wavelength conversion unit 3 is located inside the sealed unit 4.

[0101] The wavelength conversion unit 3 according to this embodiment includes, in addition to the second resonant member 31, a first wavelength conversion element 32, a second wavelength conversion element 33, a laser light separation unit 34, and a beam expander 35.

[0102] -First wavelength conversion element 32- The first wavelength conversion element 32 is composed of a nonlinear optical crystal capable of generating a second harmonic. When a fundamental wave is incident on the first wavelength conversion element 32, it doubles the frequency of the fundamental wave and emits it as a second harmonic (Second Harmonic Generation: SHG). That is, the wavelength of the laser light generated when a fundamental wave is incident on the first wavelength conversion element 32 is in the visible light range of around 500 nm. In particular, in this embodiment, the wavelength of the second harmonic is set to 532 nm.

[0103] Generally, the conversion efficiency of the fundamental wave by the first wavelength conversion element 32 is less than 100%. Therefore, at least a portion of the fundamental wave incident on the first wavelength conversion element 32 is emitted without being converted by the first wavelength conversion element 32. Consequently, when a fundamental wave is incident on the first wavelength conversion element 32, laser light containing the fundamental wave and the second harmonic is emitted.

[0104] In this embodiment, LBO (LiB3O3) was used as the first wavelength conversion element 32. However, the first wavelength conversion element 32 may not be limited to this example; KTP (KTiPO4), organic nonlinear optical materials, other inorganic nonlinear optical materials such as KN (KNbO3), KAP (KAsPO4), BBO (β-BaB2O4), LBO (LiB3O5), or bulk-type polarization reversal elements (LiNbO3 (Periodically Polled Lithium Niobate: PPLN), LiTaO3, etc.) may also be used. Furthermore, a semiconductor laser for the excitation light source of a laser using upconversion with a fluoride fiber doped with rare earth elements such as Ho, Er, Tm, Sm, and Nd can also be used. Thus, various types of optical materials can be used in this embodiment.

[0105] -Second wavelength conversion element 33- The second wavelength conversion element 33 is made of a nonlinear optical crystal capable of generating a third harmonic. The second wavelength conversion element 33 is configured to convert the incident fundamental wave and second harmonic wave into a third harmonic wave having three times the frequency of the fundamental wave (Third Harmonic Generation: THG) when they are incident on the fundamental wave and second harmonic wave (especially when the propagation directions of the fundamental wave and second harmonic wave are the same) and emit it. That is, the wavelength of the laser light generated when the fundamental wave and second harmonic wave are incident on the second wavelength conversion element 33 is in the ultraviolet region around 350 nm (specifically, near the boundary between the visible light region and the ultraviolet region). In particular, in this embodiment, the wavelength of the third harmonic wave is set to 355 nm.

[0106] Generally, the conversion efficiency of the fundamental wave by the second wavelength conversion element 33 is less than 100%. Therefore, at least a portion of both the fundamental wave and the second harmonic incident on the second wavelength conversion element 33 is emitted without being converted by the second wavelength conversion element 33. Consequently, when the fundamental wave and the second harmonic are incident on the second wavelength conversion element 33, a laser beam containing a mixture of the fundamental wave, the second harmonic, and the third harmonic is emitted.

[0107] In this embodiment, LBO (LiB3O3) was used as the second wavelength conversion element 33. However, this is not limited to this example; various types of optical materials can be used as the second wavelength conversion element 33, such as KTP (KTiPO4), organic nonlinear optical materials, or other inorganic nonlinear optical materials.

[0108] -Laser beam separation unit 34- The laser light separation unit 34 is configured to separate the third harmonic from the resonant optical path L1 of the laser light, and to emit the separated third harmonic as UV laser light from the wavelength conversion unit 3. As shown in Figure 4, the laser light separation unit 34 in this embodiment is composed of multiple optical components.

[0109] In detail, the laser beam separation unit 34 is composed of a first separator (output mirror) 34a for extracting second and third harmonics from the laser beam, and a second separator (reflection mirror) 34b for extracting the third harmonic from the laser beam.

[0110] The first separator 34a is a so-called beam splitter, configured to transmit the fundamental wave while reflecting the second and third harmonics. This first separator 34a is positioned so as to intersect with the optical axis of the resonant optical path L1 connecting the first resonant member 21 and the second resonant member 31, and is tilted at approximately 45 degrees with respect to that optical axis.

[0111] The second separator 34b is a beam splitter similar to the first separator 34a, configured to transmit the second harmonic while reflecting the third harmonic. The second separator 34b is positioned so as to intersect with the optical axis of the laser beam reflected by the first separator 34a, and is tilted at approximately 45 degrees with respect to that optical axis.

[0112] -Beam Expander 35- The beam expander 35 is composed of multiple optical lenses and is configured to direct the third harmonic (UV laser) reflected by the second separator 34b into the beam and to adjust the beam diameter of the UV laser so that it is suitable for incidence into the focus adjustment unit 53 described later. Note that the beam expander 35 can be omitted if there is no need to expand the beam diameter of the laser light.

[0113] (Sealed part 4) The sealed section 4 constitutes a sealed chamber S1 that hermetically seals the wavelength conversion section 3. The sealed section 4 also has a second transparent window 42 that allows the UV laser light generated by the wavelength conversion section 3 to exit the sealed chamber S1.

[0114] Specifically, the sealed section 4 according to this embodiment includes a housing 40, a first transparent window (referred to as the "transparent window" in the figure) 41, a second transparent window (referred to as the "output window" in the figure) 42, and a fluid connector 43.

[0115] The housing 40 surrounds the wavelength conversion unit 3 from six directions: front-to-back, up-and-down, and left-to-right. Inside the housing 40 is a sealed chamber S1 that hermetically seals the wavelength conversion unit 3 surrounded by the housing 40. The sealed chamber S1 is sealed from other spaces within the housing 10 by a material such as a sealing agent.

[0116] The first transmission window 41 transmits the fundamental laser light generated by the laser medium 23. The first transmission window 41 is provided, for example, in the wall surrounding the wavelength conversion unit 3 in the housing 40. The first transmission window 41 can be constructed, for example, by fitting a light-transmitting transparent member into a through hole formed in the wall.

[0117] As shown in Figure 4, the first transmission window 41 according to this embodiment is positioned between the laser medium 23 of the laser light generation unit 2 and the first separator 34a of the wavelength conversion unit 3. The first transmission window 41 optically couples the laser light generation unit 2 and the wavelength conversion unit 3 (see also Figure 3).

[0118] The second transmission window 42 transmits the UV laser generated by the wavelength conversion unit 3. The second transmission window 42 is provided, for example, in the wall portion surrounding the wavelength conversion unit 3 in the housing 40. The second transmission window 42 can be constructed, for example, by fitting a light-transmitting transparent member into a through hole formed in the wall portion. The second transmission window 42 is an example of a "transmission window" in this embodiment.

[0119] As shown in Figure 4, the second transmission window 42 in this embodiment is positioned between the beam expander 35 of the wavelength conversion unit 3 and the first optical member 51 of the height-direction scanning unit 5. The wavelength conversion unit 3 and the height-direction scanning unit 5 are optically coupled by the second transmission window 42 (see also Figure 3).

[0120] The fluid connector 43 allows air to flow from the air purge unit 7 into the sealed chamber S1, and allows air to flow from the sealed chamber S1 back into the air purge unit 7. The fluid connector 43 is provided, for example, in the housing 40 on the wall surrounding the wavelength conversion unit 3.

[0121] As shown in Figure 4, the fluid connector 43 according to this embodiment is composed of multiple openings (two in the illustrated example) that connect the inside and outside of the sealed chamber S1. The fluid connector 43 fluidly connects the inside of the sealed chamber S1 to the air purge unit 7.

[0122] -Regarding resonance- As shown in Figure 4, the laser excitation light incident from the excitation light generation unit 110 to the laser light generation unit 2 passes through the first optical member 22 in the laser light generation unit 2 and enters one end face of the laser medium 23. Then, the fundamental wave (fundamental laser light) emitted based on this laser excitation light passes through the first transmission window 41 and enters the wavelength conversion unit 3.

[0123] Next, the fundamental wave incident on the wavelength conversion unit 3 passes through the first separator 34a, then through the second wavelength conversion element 33, and is incident on the first wavelength conversion element 32. In the first wavelength conversion element 32, a portion of the fundamental wave is converted into the second harmonic. Therefore, the first wavelength conversion element 32 emits laser light in which the fundamental wave and the second harmonic are mixed. This laser light is totally reflected by the second resonant member 31 and retraces its optical path in the reverse direction.

[0124] The laser light then enters the first wavelength conversion element 32 again, and after the second harmonic is generated again in the first wavelength conversion element 32, it enters the second wavelength conversion element 33. In the second wavelength conversion element 33, the fundamental wave and a portion of the second harmonic are converted into the third harmonic. Therefore, the second wavelength conversion element 33 emits laser light in which the fundamental wave, second harmonic, and third harmonic are mixed. When this laser light reaches the first separator 34a, the second and third harmonics are reflected by the first separator 34a and separated from the resonant optical path, while the fundamental wave passes through the first separator 34a and reaches the first transmission window 41.

[0125] Here, the second and third harmonics separated by the first separator 34a proceed to the second separator 34b. The second separator 34b transmits and attenuates the second harmonic, while reflecting the third harmonic and guiding it to the beam expander 35. The third harmonic guided to the beam expander 35 has its beam diameter adjusted and is emitted as UV laser light through the second transmission window 42, which serves as an output window.

[0126] On the other hand, the fundamental wave that has passed through the first separator 34a and reached the first transmission window 41 passes through the first transmission window 41 and then reaches the first optical member 22 via the laser medium 23. As described above, the first optical member 22 reflects the fundamental wave propagated in this way and guides it to the Q switch 24. When the Q switch 24 is in the ON state, the fundamental wave guided to the Q switch 24 is deflected and separated from the resonant optical path L1. As described above, in this case, a continuous wave (CW) with zero or extremely low output will oscillate.

[0127] In contrast, when the Q switch 24 is in the off state, the fundamental wave passes through the Q switch 24 and reaches the first resonant member 21. The fundamental wave reflected by the first resonant member 21 passes through the Q switch 24 again, is reflected by the first optical member 22, and enters the laser medium 23. The fundamental wave that enters the laser medium 23 then enters the wavelength conversion unit 3 again.

[0128] By repeating this process, the fundamental wave is reflected multiple times between the first resonant member 21 and the second resonant member 31, resulting in amplification of the laser light. Combined with the on / off control of the Q switch 24, this causes the high-power UV laser to oscillate intermittently in pulses.

[0129] (Height direction scanning unit 5) The height-direction scanning unit 5 is interposed between the wavelength conversion unit 3 and the laser beam scanning unit 6. The height-direction scanning unit 5 optically connects the wavelength conversion unit 3 and the sealed unit 4 to the laser beam scanning unit 6.

[0130] Specifically, the height scanning unit 5 according to this embodiment comprises a first optical member 51, a second optical member 52, and the focus adjustment unit 53. These elements are arranged in order from top to bottom along the vertical direction, as shown in Figure 3.

[0131] The first optical element 51 is composed of, for example, a reflective mirror that reflects UV laser light. The first optical element 51 reflects the UV laser light emitted from the wavelength conversion unit 3 and guides it to the focus adjustment unit 53 by bending the optical axis of the UV laser light downwards.

[0132] The focus adjustment unit 53 adjusts the focal position of the UV laser light generated by the wavelength conversion unit 3. The UV laser light that has passed through the focus adjustment unit 53 is incident on the laser light scanning unit 6 via the second optical member 52.

[0133] More specifically, the focus adjustment unit 53 allows the UV laser light output from the wavelength conversion unit 3 and reflected by the first optical element 51 to pass through, and adjusts the focal position of the UV laser light.

[0134] The focus adjustment unit 53 also directs the printing laser light that has passed through the focus adjustment unit 53 toward the second optical member 52. The UV laser light that reaches the second optical member 52 is then guided through the second optical member 52 to the laser light scanning unit 6.

[0135] When adjusting the focal position, for example, the head control unit 102 operates the focus adjustment unit 53 based on a control signal output from the head control unit 102. This operation causes the focal position of the UV laser beam irradiated onto the workpiece W to shift.

[0136] The focal position of the UV laser beam is displaced to move toward and away from the output window 19 of the print head 1. In other words, the focus adjustment unit 53 functions as a means for scanning the UV laser beam in the vertical direction. Hereinafter, the scanning direction by the focus adjustment unit 53 may be referred to as the "Z direction".

[0137] The second optical element 52 is composed of, for example, a mirror that reflects UV laser light. The second optical element 52 reflects the UV laser light emitted from the focus adjustment unit 53 and guides it to the laser light scanning unit 6 by bending the optical axis of the UV laser light toward the rear.

[0138] More specifically, the second optical member 52 in this embodiment is composed of a dichroic mirror that reflects UV laser light and transmits light used for other purposes, such as imaging light for a camera.

[0139] (Laser beam scanning unit 6) The laser beam scanning unit 6 performs a two-dimensional scan of the UV laser beam emitted from the second transmission window 42 of the sealed unit 4. This two-dimensional scanning is performed within the printing area R1 illustrated in Figure 1.

[0140] More specifically, the laser beam scanning unit 6 is configured to irradiate the workpiece W with laser light (UV laser light) emitted from the second transmission window 42 and passed through the focus adjustment unit 53, and to perform a two-dimensional scan on the surface of the workpiece W (particularly within the printing area R1).

[0141] More specifically, the laser beam scanning unit 6 is composed of a so-called two-axis (X-axis and Y-axis) galvanometer scanner. That is, this laser beam scanning unit 6 has a first scanner 61 for scanning the UV laser beam incident from the focus adjustment unit 53 in a first direction, and a second scanner 62 for scanning the UV laser beam scanned by the first scanner 61 in a second direction.

[0142] Here, the second direction refers to a direction that is approximately orthogonal to the first direction. Therefore, the second scanner 62 can scan the UV laser light in a direction that is approximately orthogonal to the first scanner 61.

[0143] In this embodiment, the first direction is equal to the front-to-back direction (the longitudinal direction of the housing 10), and the second direction is equal to the left-to-right direction (the short-to-right direction of the housing 10). Hereinafter, the first direction will be referred to as the "X direction," and the second direction, which is perpendicular to it, will be referred to as the "Y direction." Both the X and Y directions are perpendicular to the aforementioned Z direction.

[0144] The first scanner 61 and the second scanner 62 each have a mirror positioned at their tip and a motor that rotates the mirror. Each mirror reflects UV laser light. Each motor adjusts the rotational position of the corresponding mirror. By adjusting the rotational position of the mirror, the reflection angle of the UV laser light by the first scanner 61 and the second scanner 62 can be adjusted. By adjusting the reflection angle of the UV laser light, the irradiation position of the UV laser light can be changed.

[0145] The laser scanning unit 6 deflects the UV laser light toward the printing area R1 by operating the first scanner 61 and the second scanner 62 according to the pre-created printing settings. The deflected UV laser light then passes through the emission window 19 provided in the housing of the print head 1 and is irradiated into the printing area R1. The desired printing pattern Pm can be printed within the printing area R1 using this UV laser light.

[0146] (Air purge unit 7) Figure 6 is a perspective view illustrating the configuration of the air purge unit 7. Figure 7 is a plan view illustrating the configuration of the air purge unit 7. Figure 8 is a perspective view illustrating the configuration of the air pump 8.

[0147] Figure 9 is a cross-sectional view illustrating the configuration of the air pump 8. Figure 10 is a plan view illustrating the configuration of the check valve 85. Figures 11 and 12 are partially enlarged views illustrating the configuration of the metal film 88, Figure 13 is a corresponding diagram to Figure 11 showing a modified example of the metal film 88, and Figure 14 is a diagram illustrating the operation of the air pump 8.

[0148] Here, Figure 9 corresponds to the IX-IX cross-section in Figure 7. Figure 10 corresponds to the view taken along arrow XX in Figure 9. Figures 11 and 12 correspond to partial cross-sections of Figure 9, respectively.

[0149] The air purge unit 7, as illustrated in Figure 4, consists of an air pump 8 and a filter 9. The air pump 8 is connected to a sealed chamber S1, which is formed by a sealed section 4. The filter 9 is located in the middle of the first flow path P1, one of two flow paths (the first flow path P1 and the second flow path P2 described later) that connects the air pump 8 and the sealed chamber S1, and which allows air to flow from the sealed chamber S1 towards the air pump 8. The filter 9 may also be located in the middle of the second flow path P2, or it may be located in both the first flow path P1 and the second flow path.

[0150] As illustrated in Figure 6, the air pump 8 and the filter 9 are fastened together by fasteners such as bolts, forming an integrated unit (air purge unit 7). The air pump 8 and the filter 9 are fluidically coupled via a first flow path P1 and a second flow path P2, etc.

[0151] -Air pump 8- The air pump 8 is connected to the inside of the sealed chamber S1. The air pump 8 is configured to circulate air between itself and the inside of the sealed chamber S1. The circulation of air by the air pump 8 is performed continuously and at all times after power is turned on to the laser printing device L, regardless of the oscillation state of the UV laser light from the device L. The term "air" as used here includes air mixed with gases, including organic gases as described later.

[0152] As illustrated in Figure 4, the air pump 8 includes a diaphragm 81, a housing 82, a pump drive unit 83, a valve seat 84, and a check valve 85.

[0153] <Diaphragm 81> The diaphragm 81 deforms in response to the application of driving force. As shown in Figure 9, the diaphragm 81, together with the housing 82, partitions the pump chamber S2. The diaphragm 81 constitutes a movable interface between the inside of the pump chamber S2 and the outside of the pump chamber S2.

[0154] More specifically, the diaphragm 81 is made of a flexible material. As an example, the diaphragm 81 in this embodiment is made of a molded rubber product and forms the bottom surface of the pump chamber S2. This bottom surface functions as the movable interface surface described above.

[0155] More specifically, the peripheral edge of the diaphragm 81 is held in place by the housing 82. The central part of the diaphragm 81 is fixed to the linear piston 832 of the pump drive unit 83 so as to displace integrally with the linear piston 832. The central part of the diaphragm 81 moves and deforms in accordance with the operation of the linear piston 832.

[0156] <Housing 82> The housing 82 separates the pump chamber S2 from the multiple communication ports 82a and 82b. The volume of the pump chamber S2 changes according to the deformation of the diaphragm 81. The multiple communication ports 82a and 82b connect the interiors of the pump chamber S2 and the sealed chamber S1, respectively.

[0157] More specifically, the housing 82 consists of a first housing 821, a second housing 822, and a third housing 823, arranged in order from the bottom of the page in Figures 8 and 9. The first housing 821, the second housing 822, and the third housing 823 are all made of resin. More specifically, the first housing 821, the second housing 822, and the third housing 823 that make up the housing 82 are all molded resin products.

[0158] As shown in Figure 9, the first housing 821 has a through hole 821a that penetrates in the vertical direction of the paper. This through hole 821a is closed by the diaphragm 81 and the linear piston 832. The linear piston 832 operates along this through hole 821a.

[0159] As shown in Figure 9, the second housing 822 is fastened to the first housing 821 above the plane of the paper. The second housing 822, together with the first housing 821, clamps the peripheral edge of the diaphragm 81 from the top and bottom directions of the paper.

[0160] Furthermore, as shown in Figure 9, the second housing 822 has a recess 824 that opens downwards toward the plane of the paper and is recessed toward the plane of the paper. This recess 824 has a roughly dome shape, and this recess 824 forms the side and ceiling surfaces of the pump chamber S2.

[0161] As mentioned above, the diaphragm 81 forms the bottom surface of the pump chamber S2. The central part of the diaphragm 81 deforms as it moves in conjunction with the operation of the linear piston 832. The direction of this movement corresponds to moving closer to or further away from the ceiling surface of the pump chamber S2.

[0162] Therefore, the volume of the pump chamber S2 can be changed by moving and deforming the diaphragm 81. Specifically, when the diaphragm 81 is moved and deformed in a direction that approaches the ceiling surface of the pump chamber S2, the volume of the pump chamber S2 decreases. Also, when the diaphragm 81 is moved and deformed in a direction that moves away from the ceiling surface of the pump chamber S2, the volume of the pump chamber S2 decreases.

[0163] As shown in Figure 9, the third housing 823 is fastened to the second housing 822 above the plane of the paper. The third housing 823, together with the second housing 822, clamps the peripheral edge of the check valve 85 (described later) from the top and bottom directions of the paper. The central part of the check valve 85 is spaced apart from either the third housing 823 or the second housing 822.

[0164] Returning to the configuration of the pump chamber S2, the third housing 823 has a first communication port 82a, and the second housing 822 has a second communication port 82b. Although not shown in the diagram, the first communication port 82a and the second communication port 82b each have a roughly circular cross-sectional shape.

[0165] The first communication port 82a connects the inside of the sealed chamber S1 and the inside of the pump chamber S2 via the first flow path P1. As shown in Figures 4 and 9, the first flow path P1 is a flow path for introducing air from the sealed chamber S1 to the pump chamber S2. The first communication port 82a constitutes the downstream end of the first flow path P1. The first communication port 82a is a communication port configured to send air from the sealed chamber S1 to the pump chamber S2.

[0166] The second communication port 82b connects the inside of the sealed chamber S1 and the inside of the pump chamber S2 via the second flow path P2. As shown in Figures 4 and 9, the second flow path P2 is a flow path for introducing air from the pump chamber S2 to the sealed chamber S1. The second communication port 82b constitutes the upstream end of the second flow path P2. The second communication port 82b is a communication port configured to send air from the pump chamber S2 to the sealed chamber S1.

[0167] Here, the first flow path P1 and the second flow path P2 allow air to flow from the sealed chamber S1 to the pump chamber S2 via the first flow path P1, and air to flow from the pump chamber S2 to the sealed chamber S1 via the second flow path P2. As shown in Figure 4, the first flow path P1 and the second flow path P2 constitute a circulating flow path P0 that circulates air between the sealed chamber S1 and the pump chamber S2.

[0168] More specifically, the first channel P1 and the second channel P2 are partitioned within the second housing 822 and the third housing 823, respectively. The first channel P1 has a first accommodation space S31 surrounding the opening edge of the first communication port 82a. The second channel P2 has a second accommodation space S32 surrounding the opening edge of the second communication port 82b.

[0169] The first housing space S31 and the second housing space S32 are both partitioned between a recess provided on the lower end surface (lower end surface on the plane of the paper) of the third housing 823 and a recess provided on the upper end surface (upper end surface on the plane of the paper) of the second housing 822. These recesses are arranged to face each other in the vertical direction of the paper.

[0170] The first communication port 82a opens toward the upper end surface of the second housing 822 in the first accommodation space S31. The first communication port 82a connects the first flow path P1 to the first accommodation space S31.

[0171] The first housing space S31 is further connected to an inlet port 86 that connects the first housing space S31 to the pump room S2. The inlet port 86 opens to the upper end surface of the second housing 822.

[0172] The inlet port 86 is positioned parallel to the central axis Oc1 that penetrates the opening surface of the first communication port 82a, and offset radially (for example, in the direction that penetrates the plane of the paper in Figure 9) with respect to the central axis Oc1. This arrangement prevents the inlet port 86 from being closed by the check valve 85 when the check valve 85 moves away from the first communication port 82a.

[0173] The second communication port 82b opens toward the lower end surface of the third housing 823 in the second housing space S32. The second communication port 82b connects the pump room S2 to the second housing space S32.

[0174] The second housing space S32 is further connected to an outlet port 87 that connects the second housing space S32 to the second flow path P2. The outlet port 87 opens to the lower end surface of the third housing 823. The outlet port 87 is positioned parallel to the central axis Oc2 that penetrates the opening surface of the second communication port 82b, and radially offset with respect to the central axis Oc2. This arrangement prevents the outlet port 87 from being closed by the check valve 85 when the check valve 85 moves away from the second communication port 82b.

[0175] The inlet port 86 and the outlet port 87 can be considered as flow paths connecting the pump chamber S2 and the communication ports 82a and 82b. At least a portion of the inlet port 86 and the outlet port 87 is covered with a metal film.

[0176] In this embodiment, the entire inner walls of the inlet port 86 and the outlet port 87 are covered with a metal film. Furthermore, in this embodiment, the flow path connecting the first communication port 82a and the first flow path P1, the flow path connecting the second communication port 82b and the pump chamber S2, and the first and second accommodation spaces S31 and S32 are also covered with a metal film.

[0177] <Venus 84> The valve seat 84 is provided in the housing 82. The valve seat 84 is positioned around each of the multiple communication openings 82a, 82b. The valve seat 84 according to this embodiment includes a first valve seat 841 positioned around the first communication opening 82a, i.e., inside the first housing space S31, and a second valve seat 842 positioned around the second communication opening 82b, i.e., inside the second housing space S32.

[0178] The first valve seat 841 is formed as an annular protrusion on the opening edge of the first communication port 82a, raised toward the inlet port 86. The second valve seat 842 is formed as an annular protrusion on the opening edge of the second communication port 82b, raised toward the outlet port 87. In other words, the first valve seat 841 is continuous with the first communication port 82a of the third housing 823. The second valve seat 842 is continuous with the second communication port 82b of the second housing 822.

[0179] In other words, the first valve seat 841 is formed integrally with the third housing 823 which constitutes the housing 82 by resin molding, and the second valve seat 842 is formed integrally with the second housing 822 which constitutes the housing 82 by resin molding.

[0180] Thus, in this embodiment, the valve seat 84, which includes the first valve seat 841 and the second valve seat 842, is formed integrally with the housing 82. In other words, the first valve seat 841 and the second valve seat 842 are not separate components from the housing 82. However, it is not essential to form the valve seat 84 and the housing 82 integrally.

[0181] Furthermore, in this embodiment, the housing 82 is covered with a metal film. In other words, the outer surface of the housing 82, the inner surface forming the air passage of the housing 82, and the first and second valve seats 841 and 842 can be covered with a metal film by immersing the housing 82, which is not a separate component from the housing 82, in a plating solution.

[0182] <Check valve 85> The check valves 85 are attached to each of the valve seats 84. The check valves 85 make contact with or separate from the valve seats 84 in accordance with the change in volume of the pump chamber S2 due to the operation of the pump drive unit 83 (deformation of the diaphragm 81).

[0183] More specifically, the check valve 85 is made of a flexible member. As an example, the check valve 85 according to this embodiment is made of a rubber sheet (hereinafter referred to as a valve sheet).

[0184] Furthermore, as illustrated in Figures 9 and 10, the check valve 85 according to this embodiment is integrally constructed from a single component, comprising a portion that is in close contact with or separated from the first valve seat 841 (first check valve 851) and a portion that is in close contact with or separated from the second valve seat 842 (second check valve 852).

[0185] Specifically, the check valve 85 according to this embodiment is composed of a single valve seat common to the first valve seat 841 and the second valve seat 842. The valve seat is an example of the "single component" described above.

[0186] The check valve 85, formed by the valve seat, can be divided into two regions: one that contributes to the opening and closing of the first valve seat 841, and another that contributes to the opening and closing of the second valve seat 842. Hereinafter, the former region will be referred to as the first check valve 851, and the latter region as the second check valve 852. As shown in Figure 10, the first check valve 851 and the second check valve 852 are integrally formed in this embodiment.

[0187] As shown in Figure 10, the first check valve 851 has a first closing portion 851a located in the center of the first check valve 851 and closing the first communication port 82a, and a first communication portion 851b provided around the first closing portion 851a and cut out to communicate with the inlet port 86. The first communication portion 851b is composed of a gap having a substantially C shape.

[0188] The first check valve 851 is either in close contact with or separated from the first valve seat 841. When the volume of the pump chamber S2 is relatively large, or when the air pump 8 is not driven, the first check valve 851 brings the first closing portion 851a in close contact with the first valve seat 841 and separates the first communicating portion 851b from the inlet port 86. In this state, the inflow of air into the pump chamber S2 via the first flow path P1 is suppressed (see the lower part of Figure 14).

[0189] On the other hand, when the volume of the pump chamber S2 is relatively small, the first check valve 851 separates the first closing portion 851a from the first valve seat 841 and brings the first communicating portion 851b closer to the inlet port 86. In this state, the inflow of air into the pump chamber S2 via the first flow path P1 is permitted (see the upper part of Figure 14).

[0190] By offsetting the inlet port 86 with respect to the central axis Oc1 of the first communication opening 82a, the inlet port 86 is prevented from being blocked by the first blocking portion 851a, which is spaced apart from the first valve seat 841 (see Figure 10).

[0191] As also shown in Figure 10, the second check valve 852 has a second closing portion 852a located in the center of the second check valve 852 and closing the second communication port 82b, and a second communication portion 852b provided around the second closing portion 852a and cut out to communicate with the outlet port 87. The second communication portion 852b is composed of a gap having a shape that is mirror-symmetric with respect to the first communication portion 851b.

[0192] Furthermore, the shape of the gap constituting the second connecting portion 852b is not limited to a shape that is mirror-symmetric with respect to the first connecting portion 851b. For example, the second connecting portion 852b may be composed of a gap having a shape rotated 90° with respect to the first connecting portion 851b.

[0193] The second check valve 852 is either in close contact with or separated from the second valve seat 842. When the volume of the pump chamber S2 is relatively small, or when the air pump 8 is not driven, the second check valve 852 brings the second closing portion 852a in close contact with the second valve seat 842 and separates the second communicating portion 852b from the outlet port 87. In this state, the inflow of air into the pump chamber S2 via the second flow path P2 is suppressed (see the upper part of Figure 14).

[0194] On the other hand, when the volume of the pump chamber S2 is relatively large, the second check valve 852 separates the second closing portion 852a from the second valve seat 842 and brings the second communicating portion 852b closer to the outlet port 87. In this state, the outflow of air from the pump chamber S2 via the second flow path P2 is permitted (see the lower part of Figure 14).

[0195] By offsetting the outlet port 87 with respect to the central axis Oc2 of the second communication port 82b, the closure of the outlet port 87 by the second closure portion 852a, which is spaced apart from the second valve seat 842, is prevented (see Figure 10).

[0196] <Pump drive unit 83> The pump drive unit 83 applies driving force to the diaphragm 81, thereby circulating air between the inside of the pump chamber S2 and the sealed chamber S1 via multiple communication ports 82a and 82b.

[0197] More specifically, the pump drive unit 83 changes the volume of the pump chamber S2 by applying a driving force to the diaphragm 81. The pump drive unit 83 makes the check valve 85 tightly press against or separate from the valve seat 84 in accordance with the change in the volume of the pump chamber S2. The pump drive unit 83 circulates air between the inside of the pump chamber S2 and the sealed chamber S1 via multiple communication ports 82a and 82b through the tightening or loosening of the check valve 85 against the valve seat 84 and the change in the volume of the pump chamber S2.

[0198] More specifically, the pump drive unit 83 according to this embodiment includes a motor 831 and a linear piston 832, as illustrated in Figures 8 and 9. The motor 831 has a shaft that rotates in response to a control signal from the print controller 100. The linear piston 832 is connected to the tip of this shaft. The linear piston 832 converts the rotation of the shaft into reciprocating motion in the vertical direction of the paper, as shown in Figure 9. This reciprocating motion allows the diaphragm 81 to move back and forth along a desired direction.

[0199] As the diaphragm 81 moves back and forth, the volume of the pump chamber S2 changes, as described above. This change in volume causes air to circulate between the pump chamber S2 and the sealed chamber S1.

[0200] For example, when the volume of the pump chamber S2 increases, as shown in the upper part of Figure 14, the first check valve 851 opens the first communication port 82a and the second check valve 852 closes the second communication port 82b. As a result, backflow through the second flow path P2 is suppressed, while air is drawn out from the sealed chamber S1 to the pump chamber S2 through the first flow path P1.

[0201] On the other hand, when the volume of the pump chamber S2 decreases, as shown in the lower part of Figure 14, the first check valve 851 closes the first communication port 82a and the second check valve 852 opens the second communication port 82b. As a result, backflow through the first flow path P1 is suppressed, while air is discharged from the pump chamber S2 to the sealed chamber S1 via the second flow path P2.

[0202] -Filter 9- The filter 9 is positioned in the middle of the flow path (second flow path P2 in this embodiment) connecting the pump chamber S2 and the sealed chamber S1. The filter 9 is made of a porous adsorbent such as synthetic zeolite or activated carbon, and removes impurities contained in the air flowing through the second flow path P2.

[0203] <5. Regarding the suppression of adhesion> As described above, impurities can be actively removed from the wavelength conversion unit 3 by circulating air with the air pump 8. In using the air pump 8, it is conceivable to improve the sealing performance between the check valve 85 that constitutes the air pump 8 and the valve seat 84 on which the check valve 85 sits in order to ensure the pump pressure.

[0204] For example, if the surface of the valve seat 84 is excessively rough, the sealing performance cannot be ensured, which may be problematic in securing pump pressure. In order to improve the sealing performance between the valve seat 84 and the check valve 85, the seating surface 84a of the valve seat 84 (the surface on which the check valve 85 sits) must be smooth.

[0205] On the other hand, the wavelength conversion unit 3 for the laser printing device L illustrated in Figure 4 is required to be as clean as possible to prevent the generation of impurities. Therefore, the flow paths connecting the wavelength conversion unit 3 and the air pump 8 (for example, the first flow path P1 and the second flow path P2), as well as the components of the air pump 8, including the check valve 85, are typically used in a degreased and clean state.

[0206] The inventors of this application noticed that when the air pump 8 is operated in such a clean environment, if the aforementioned seating surface is too smooth, the check valve 85 and the seating surface 84a may stick together while remaining sealed, potentially interfering with the operation of the air pump 8.

[0207] The inventors of the present invention also noticed that the likelihood of adhesion increases, particularly when the materials of the check valve 85 and the surface of the seat 84a are composed of a combination of rubber and metal.

[0208] In other words, by maximizing the sealing performance, backflow by the check valve 85 is suppressed to the greatest extent possible, resulting in minimal backflow into the pump chamber S2 and maximizing the efficiency of air delivery from the pump chamber S2 to the sealed chamber S1. Consequently, the maximum pressure of the air pump 8 is increased.

[0209] However, if the check valve 85 and the seat surface 84a become stuck together while sealed, the suppression of backflow as described above may backfire, making it impossible to release the sticking by utilizing the backflow between the primary and secondary sides of the check valve 85. In other words, the relative pressure increase on the primary side caused by the reciprocating motion of the diaphragm 81 may not be sufficient to separate the stuck check valve 85 from the seat surface 84a, making it impossible to release the sticking.

[0210] The laser printing device L is used in a variety of environments depending on the user's application, and depending on the ambient temperature, it must be assumed that such adhesion is a real possibility.

[0211] Furthermore, the inventors of this application realized that, in order to remove impurities from the wavelength conversion unit 3, it is sufficient for the air pump 8, which can reach a maximum pressure of about 100 kPa, to operate at a pump pressure of 3 kPa to 10 kPa, and that excessive pump pressure is not required compared to other general applications.

[0212] In light of the above findings, the inventors of this application conducted thorough research and came up with a new idea: that by controlling the sealing properties of the seat surface 84a within the range in which the desired pump pressure is secured, it is possible to achieve both the pump pressure of the air pump 8 and the suppression of adhesion as described above, and arrived at the following configuration.

[0213] Specifically, as shown in Figures 11 and 12, the valve seat 84 according to this embodiment has a portion that is in close contact with or separated from the check valve 85 in accordance with the volume change of the pump chamber S2 covered with a metal film 88. This metal film 88 forms an uneven surface 89 on the surface of the valve seat 84. This metal film 88 is provided on at least one (both in this embodiment) of the first valve seat 841 and the second valve seat 842. By controlling the degree of unevenness in the uneven surface 89, the sealing performance of the seat surface 84a can be controlled.

[0214] Furthermore, the metal film 88 according to this embodiment is formed, for example, by applying a plating treatment to the surface of a housing 82, which is a resin molded product. By adjusting the film formation conditions of the plating treatment, the degree of unevenness in the uneven shape 89 of the metal film 88 can be adjusted. Therefore, by performing the plating treatment under the same film formation conditions, an uneven shape 89 with a desired degree of unevenness can be formed on the metal film 88 with good reproducibility. In other words, tolerances of the uneven shape 89 can be suppressed, so the sealing performance of the seating surface 84a can be controlled with high precision. For example, the degree of unevenness can be adjusted through one or more of the current density in the plating treatment, the composition of the plating solution, the temperature of the plating solution, and the stirring speed of the plating solution.

[0215] Furthermore, the uneven shape 89 of the metal film 88 may be formed by applying a predetermined metal processing to the metal film 88 formed by the plating process. In this case, blasting processes such as sandblasting, blower blasting, and shot blasting may be used for the metal processing, or polishing processes such as grinding wheel polishing, barrel polishing, buff polishing, and electrolytic polishing may be used.

[0216] As shown in Figure 13, the uneven shape 89 may be formed by applying a textured finish to the surface of the mold for forming the housing 82 in advance, instead of or in addition to the metalworking. In this case, as a result of the formation of the unevenness 91 on the surface of the housing 82, the metal film 88' covered on the unevenness 91 will also consequently have an uneven shape 89' that follows the unevenness 91 on the surface of the housing 82.

[0217] For example, a desired rough surface 91 is formed on the surface of the housing 82 by texturing, and the film formation conditions for the plating process are finely adjusted. In this way, a desired fine surface 89' can be formed on top of the rough surface 91 created by texturing by the plating process, thereby creating a surface shape 89'. In other words, the sealing performance of the seating surface 84a can be controlled with greater precision.

[0218] Thus, the uneven shape 89 according to this embodiment may be formed on a metal film 88 formed on a flat seating surface 84a, or it may be formed on a metal film 88 as a result of applying metal plating to the uneven seating surface 84a.

[0219] Furthermore, the degree of unevenness in the uneven shape 89 can be defined, for example, by the surface roughness of the metal film 88. This surface roughness can be defined, for example, by the arithmetic mean roughness (Ra). Specifically, the surface roughness of the metal film 88 according to this embodiment is set to a range of, for example, Ra 0.4 or more and Ra 25 or less, preferably Ra 1.6 or more and Ra 12.5 or less, and even more preferably Ra 3.2 or more and Ra 6.3 or less.

[0220] <6. Adhesion-inhibiting effect> As described above, according to the embodiment, as illustrated in Figures 11 to 13, a part of the valve seat 84 is covered with a metal film 88. The metal film 88 forms an uneven shape 89, which suppresses adhesion between the valve seat 84 and the check valve 85. This achieves both stabilization of the operation of the air pump 8 and keeping the inside of the wavelength conversion unit 3 clean, and consequently, stabilizes the output of the UV laser light.

[0221] Furthermore, as illustrated in Figures 11 to 13, covering at least a portion of the valve seat 84 with a metal film 88 offers superior control over its surface condition compared to a configuration in which the entire valve seat 84 or check valve 85 is made of metal. Therefore, the surface condition of the metal film 88 (for example, the degree of unevenness of the metal film 88) can be kept within an appropriate range to achieve both the suppression of adhesion between the valve seat 84 and the check valve 85 and the sealing performance.

[0222] Furthermore, as illustrated in Figure 4, by placing the filter 9 in the middle of the first flow path P1, impurities can be effectively removed from the wavelength conversion unit 3 without excessively increasing the pump pressure of the air pump 8. This creates a margin of sealing between the valve seat 84 and the check valve 85, making it possible to suppress adhesion between the two components 84 and 85.

[0223] Furthermore, as explained with reference to Figure 14, etc., if the check valve 85 is flexible, adhesion between the valve seat 84 and the check valve 85 becomes an even greater concern. The above embodiment is particularly effective under such circumstances.

[0224] Furthermore, generally speaking, a resin housing 82 is not thought to adhere as much to the check valve 85 as a metal housing. However, a resin housing 82 is undesirable because it allows organic gases to permeate it.

[0225] In contrast, as in the embodiment described above, the permeation of organic gases as described above can be suppressed by covering the valve seat 84 and the flow path within the housing 82 with a metal film 88.

[0226] <7. Other Embodiments> Figure 15 is a partially enlarged view showing a further modification of the metal film 88.

[0227] In the above embodiment, the seating surface 84a of the valve seat 84 was covered with a metal film 88 that formed an uneven shape 89 on the seating surface 84a, and the check valve 85 that is in close contact with or separated from the seating surface 84a was made of a rubber valve seat. However, the present disclosure is not limited to such configurations. As shown in Figure 15, the check valve 85 may be covered with a metal film 88" that forms an uneven shape 89" on its surface. This metal film 88" covers the portion that is in close contact with or separated from the valve seat 84 in accordance with the volume change of the pump chamber S2. For example, this metal film 88" may cover the portion of the check valve 85 that faces the valve seat 84.

[0228] In this case, the seating surface 84a of the valve seat 84 that is in close contact with or separated from the check valve 85 may be made of rubber. For example, the valve seat 84 may be molded from rubber, and the check valve 85 may be made of a deformable metal valve seat such as a leaf spring. Then, by plating the metal valve seat, a metal film 88" that forms an uneven shape 89" as shown in Figure 15 can be formed on the surface of the valve seat.

[0229] In this way, by covering at least a portion of the check valve 85 with a metal film 88" and having the metal film 88" form an uneven shape 89", it is possible to achieve both stabilization of the operation of the air pump 8 and keeping the inside of the wavelength conversion unit 3 clean, as in the above embodiment, and consequently, to stabilize the output of the UV laser light.

[0230] Furthermore, covering at least a portion of the check valve 85 with a metal film 88" offers superior control over its surface condition compared to a configuration in which the valve seat 84 or the entire check valve 85 is made of metal. As a result, the surface condition of the metal film 88" (for example, the degree of unevenness of the metal film 88") can be kept within an appropriate range.

[0231] Furthermore, as illustrated in Figure 10, in the above embodiment, the first check valve 851 and the second check valve 852 were composed of a single component (a single valve seat), but the configuration is not limited to this. The valve seat constituting the first check valve 851 and the valve seat constituting the second check valve 852 may be separate components. [Explanation of Symbols]

[0232] S Laser Printing System L Laser Printing Device 1. Print head 2. Laser light generation unit 3. Wavelength conversion section 4 Sealed part 41 First transparent window 42. Second transparent window (transparent window) 5. Height scanning unit 53 Focus adjustment section 6. Laser beam scanning unit 7. Air purge unit 8. Air pump 81 Diaphragm 82 Housing 82a 1st communication port (communication port) 82b 2nd communication port (communication port) 83 Pump drive unit 84 valve seats 84a Seat surface (parts that are in contact or separated) 841 First valve seat 842 Second valve seat 85 Check valve 851 First check valve 852 Second check valve 88. Vesicle 89 Uneven shape 88" Metal film 89” uneven shape 9 filters 100 Print Controller 110 Excitation light generation unit S1 Closed room S2 Pump Room P1 First channel P2 Second channel P0 circulation channel Double job

Claims

1. An excitation light generation unit that generates excitation light, A laser light generation unit generates fundamental laser light based on the excitation light generated by the excitation light generation unit, A wavelength conversion unit generates UV laser light based on the fundamental laser light generated by the laser light generation unit, A sealed chamber is provided to airtightly seal the wavelength conversion unit, and the sealed chamber has a transparent window through which the UV laser light generated by the wavelength conversion unit is emitted to the outside of the sealed chamber. A laser beam scanning unit that performs two-dimensional scanning of the UV laser beam emitted from the aforementioned transmission window, An air pump that communicates with the inside of the sealed chamber and circulates air between it and the inside of the sealed chamber, Equipped with, The aforementioned air pump is A diaphragm that deforms in response to the application of driving force, A housing that separates a pump chamber whose volume changes according to the deformation of the diaphragm, and a plurality of communication ports that connect the inside of the pump chamber and the sealed chamber, A pump drive unit that circulates air between the inside of the pump chamber and the sealed chamber via a plurality of communication ports by applying a driving force to the diaphragm, A valve seat provided in the housing and arranged around each of the plurality of communication openings, A check valve is attached to each of the valve seats and moves in close contact with or away from the valve seat in accordance with the volume change of the pump chamber caused by the pump drive unit, It has, The valve seat is covered with a metal film that forms an uneven surface on the surface of the valve seat, in which the portion that comes into contact with or separates from the check valve in accordance with the volume change of the pump chamber is covered with a metal film that forms an uneven surface. A laser printing device characterized by the following features.

2. In the laser printing apparatus described in claim 1, A filter is provided in the middle of the flow path connecting the pump chamber and the sealed chamber to remove impurities contained in the air flowing through the flow path. A laser printing device characterized by the following features.

3. In the laser printing apparatus described in claim 1, The aforementioned check valve is made of a flexible member. A laser printing device characterized by the following features.

4. In the laser printing apparatus described in claim 1, The aforementioned housing is made of resin, At least a portion of the flow path connecting the pump chamber and the communication port is covered with a metal film. A laser printing device characterized by the following features.

5. In the laser printing apparatus described in claim 1, The valve seat is formed integrally with the housing, The housing is covered with a metal film. A laser printing device characterized by the following features.

6. In the laser printing apparatus described in claim 1, The multiple communication ports are, A first communication port for supplying air from the sealed chamber to the pump chamber, It includes a second communication port for supplying air from the pump chamber to the sealed chamber, The aforementioned valve seat is A first valve seat arranged around the first communication opening, It has a second valve seat arranged around the second communication opening, The check valve is configured such that the portion that is in contact with or separated from the first valve seat and the portion that is in contact with or separated from the second valve seat are integrally formed by a single component. A laser printing device characterized by the following features.

7. An excitation light generation unit that generates excitation light, A laser light generation unit generates fundamental laser light based on the excitation light generated by the excitation light generation unit, A wavelength conversion unit generates UV laser light based on the fundamental laser light generated by the laser light generation unit, A sealed chamber is provided to airtightly seal the wavelength conversion unit, and the sealed chamber has a transparent window through which the UV laser light generated by the wavelength conversion unit is emitted to the outside of the sealed chamber. A laser beam scanning unit that performs two-dimensional scanning of the UV laser beam emitted from the aforementioned transmission window, An air pump that communicates with the inside of the sealed chamber and circulates air between it and the inside of the sealed chamber, Equipped with, The aforementioned air pump is A diaphragm that deforms in response to the application of driving force, A housing that separates a pump chamber whose volume changes according to the deformation of the diaphragm, and a plurality of communication ports that connect the inside of the pump chamber and the sealed chamber, A pump drive unit that circulates air between the inside of the pump chamber and the sealed chamber via a plurality of communication ports by applying a driving force to the diaphragm, A valve seat provided in the housing and arranged around each of the plurality of communication openings, A check valve is attached to each of the valve seats and moves in close contact with or away from the valve seat in accordance with the volume change of the pump chamber caused by the pump drive unit, It has, The check valve is covered with a metal film that forms an uneven surface on the surface of the check valve, in which the portion that comes into contact with or separates from the valve seat in accordance with the volume change of the pump chamber is covered with a metal film that forms an uneven surface. A laser printing device characterized by the following features.

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