CN220742451U - Transfer printing apparatus - Google Patents

Abstract

A transfer printing apparatus includes a liquid supply assembly, a first roller, a second roller, and a first driving member. The liquid supply assembly is used for providing PI liquid; the first roller is rotationally connected with the liquid supply assembly, and is used for receiving PI liquid provided by the liquid supply assembly and uniformly distributing the PI liquid on the peripheral surface of the first roller; the second roller is rotationally connected with the first roller, receives PI liquid on the first roller, and the PI liquid is distributed on the outer peripheral surface of the second roller according to a preset pattern; the first driving piece is connected with the first roller and the second roller and drives the liquid supply assembly, the first roller and the second roller to move between an initial position and a preset position at the same time. The transfer printing equipment can solve the problem of low efficiency in PI film printing.

Description

Transfer printing apparatus

Technical Field

The utility model relates to the technical field of display, in particular to transfer printing equipment.

Background

PI films are commonly used in the semiconductor field and are an irreplaceable film layer in TFT-LCDs. The film layer needs good material characteristics, particularly solvent resistance, wear resistance, insulativity and high voltage retention rate, so that only PI (polyimide) materials in the current LCD field meet the production requirements.

From the coating mode, the current mass production in industry mainly uses Ink JET printing (Ink JET, hereinafter abbreviated as IJ) and plate transfer printing (Roller Coater, hereinafter abbreviated as RC). The RC type film surface uniformity and high coating accuracy are not achieved by IJ type, and therefore each has merits and merits.

However, due to the limitation of the RC type structure, the transfer roller needs to be reset to perform re-feeding (liquid feeding) after each transfer, so that the RC type transfer efficiency is low, and the productivity and the cost are greatly limited.

Disclosure of Invention

The utility model aims to provide transfer printing equipment which solves the problem of low efficiency in PI film printing.

In order to achieve the purpose of the utility model, the utility model provides the following technical scheme:

the utility model provides transfer printing equipment, which is used for carrying out pattern transfer printing on a piece to be printed, wherein the piece to be printed is fixed at a preset position; the transfer printing equipment comprises a liquid supply assembly, a first roller, a second roller and a first driving piece; the liquid supply assembly is used for providing PI liquid; the first roller is rotationally connected with the liquid supply assembly, and is used for receiving PI liquid provided by the liquid supply assembly and uniformly distributing the PI liquid on the peripheral surface of the first roller; the second roller is rotationally connected with the first roller, receives PI liquid on the first roller, and the PI liquid is distributed on the outer peripheral surface of the second roller according to a preset pattern; the first driving piece is connected with the first roller and the second roller and drives the liquid supply assembly, the first roller and the second roller to move between an initial position and a preset position at the same time.

In one embodiment, the diameter of the first roller is smaller than the diameter of the second roller.

In one embodiment, the transfer apparatus further comprises: the support frame is connected with the first driving piece, the first roller and the second roller are both arranged on the support frame, and the first driving piece drives the support frame to move; the second driving piece is arranged on the supporting frame and is in transmission connection with the first roller so as to drive the first roller to rotate; and the third driving piece is arranged on the supporting frame and is in transmission connection with the second roller so as to drive the second roller to rotate.

In one embodiment, the transfer printing apparatus further comprises a recovery member mounted on the support frame, the recovery member being configured to recover PI liquid overflowed from the first roller.

In one embodiment, the liquid supply assembly comprises:

the liquid supply piece is used for providing the PI liquid;

and the guide piece is rotationally connected with the first roller and used for receiving PI liquid provided by the liquid supply piece, and the guide piece is kept static when the first roller rotates.

In one embodiment, the transfer device comprises a working surface for supporting a part to be printed, the guide member comprises a guide surface which receives the PI liquid, and an included angle is formed between the guide surface and the working surface.

In one embodiment, the outer surface of the first roller is provided with a groove, and the guide member extends into the groove and guides the PI liquid into the groove.

In one embodiment, the number of the grooves is plural, and the volume of any one groove is 60PL to 90PL.

In one embodiment, the transfer printing device further comprises a workbench, the workbench comprises a working surface, the working surface is used for supporting a piece to be printed, the first roller and the second roller move on the working surface, a vacuum hole is further formed in the working surface, and air pressure in the vacuum hole is smaller than normal pressure.

In one embodiment, the workbench further comprises a positioning part, wherein the positioning part is located on the working surface and used for determining that the to-be-printed piece is placed at a preset position.

According to the utility model, the first driving piece is arranged to drive the liquid supply assembly, the first roller and the second roller to move between the initial position and the preset position, so that the first roller and the second roller can synchronously move, the first roller is used for homogenizing liquid and transferring PI liquid to the second roller, and therefore, feeding in the coating process can be realized, the process of reciprocating feeding in the coating process can be reduced, and the coating efficiency is improved; in addition, the liquid supply assembly, the first roller and the second roller are connected in series to form a whole, so that the integration degree is higher; meanwhile, the movable position can be regulated and controlled through the first driving piece, the area to be maintained is more controllable, and the maintenance safety is better.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the utility model, and that other drawings can be obtained from them without inventive effort for a person skilled in the art.

FIG. 1 is a schematic top view of a transfer apparatus of an embodiment;

FIG. 2 is a schematic side view of a transfer apparatus of an embodiment;

FIG. 3 is an enlarged schematic view of a first roller and a second roller of an embodiment.

Reference numerals illustrate:

100-transfer apparatus, 1-liquid supply unit, 1A-liquid supply unit, 1B-guide unit, 1B 1-guide surface, 2-first roller, 2A-groove, 3-second roller, 3A-transfer plate, 3B-roller, 4-first driving unit, 5-table, 5A-working surface, 6-supporting frame, 7-second driving unit, 8-third driving unit, 9-guide rail, 10-recovery unit, 11-vacuum hole, 12-vacuum line, 13-positioning unit, 200-printing unit,

Detailed Description

The following description of the embodiments of the present utility model will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, are intended to fall within the scope of the present utility model.

It will be understood that when an element is referred to as being "fixed to" another element, it can be directly on the other element or intervening elements may also be present. When a component is considered to be "connected" to another component, it can be directly connected to the other component or intervening components may also be present.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this utility model belongs. The terminology used in the description of the utility model herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the utility model. The term "and/or" as used herein includes any and all combinations of one or more of the associated listed items.

Some embodiments of the present utility model are described in detail below with reference to the accompanying drawings. The following embodiments and features of the embodiments may be combined with each other without conflict.

The present utility model provides a transfer apparatus 100, the transfer apparatus 100 being used for performing pattern transfer on a piece to be printed fixed at a preset position.

In one embodiment, referring to fig. 1 to 3, a transfer apparatus includes a liquid supply assembly 1, a first roller 2, a second roller 3, and a first driving member 4. The liquid supply assembly 1 is used for providing Polyimide (PI liquid for short); the first roller 2 is rotationally connected with the liquid supply assembly 1, and the first roller 2 receives PI liquid provided by the liquid supply assembly 1 and uniformly distributes the PI liquid on the peripheral surface of the first roller 2; the second roller 3 is rotationally connected with the first roller 2, the second roller 3 receives PI liquid on the first roller 2, and the PI liquid is distributed on the outer peripheral surface of the second roller 3 according to a preset pattern; the first driving member 4 connects the first roller 2 and the second roller 3, and drives the liquid supply assembly 1, the first roller 2, and the second roller 3 to move between the initial position and the preset position at the same time.

Specifically, the transfer apparatus 100 further includes a table 5, and a member to be printed is placed on the table 5. The liquid supply assembly 1, the first roller 2 and the second roller 3 are driven by a driving member to reciprocate on the surface of the workbench 5. The second rolling will also contact the piece to be printed on the surface of the table 5, thereby transferring the PI liquid of the outer peripheral surface to the piece to be printed.

Alternatively, the part to be printed 200 is a glass substrate. The method is mainly used for etching the TFT component circuit and the color film.

Alternatively, the liquid supply assembly 1 may have a function of receiving and supplying a solution. The liquid supply assembly 1 discharges PI liquid onto the first roller 2.

Alternatively, the first roller 2 may be connected to the second roller 3 and rotated so that the PI liquid received is uniformly distributed on the outer peripheral surface thereof.

Optionally, the second roller 3 includes a roller body 3B and a transfer plate 3A, where the transfer plate 3A is sleeved on the outer surface of the roller body 3B. The rotation of the second roller 3 can drive the rotation of the transfer plate 3A along with the rotation. It will be appreciated that the transfer plate 3A may be a resin stencil made in accordance with variables such as the size of the part to be printed, the parameters of the first roll 2, the parameters of the RC coater, etc.

Optionally, the outer surface of the transfer plate 3A has a first pattern engraved thereon, and the member to be printed has a second pattern thereon. The first template has the preset pattern as described above, and PI on the first roller 2 may also be transferred to the first template and temporarily stored. And then the PI liquid on the first sample plate is transferred to a corresponding second sample plate on the piece to be printed along with the movement and rotation of the second roller 3.

Alternatively, the second template on the part to be printed may have a different size, for example 55 inches/43 inches/32 inches.

Alternatively, the transfer plate 3A is fixed to the outer surface of the roller body 3B. The transfer plate 3A and the roller body 3B can be fixedly connected through a clamping groove, or fixedly connected through adhesive, or fixedly connected through magnetic attraction. It can be understood that the fixing manner is not limited, but the fixing manner is to fix the transfer printing plate 3A on the roller body 3B, so that the transfer printing plate 3A cannot be deformed and slid by extension even if the transfer printing plate 3A is subjected to the action of printing external force, the transfer printing plate 3A is prevented from being deformed and slid by extension, the production printing cannot be deviated, and the product quality is ensured to the greatest extent.

Alternatively, the first driving member 4 may be a linear motor.

Alternatively, the initial position is the position where the second roller 3 stays before transferring (i.e., the right side in the figure), and the preset position is the position where the second roller 3 stays after finishing transferring (i.e., the left side in the figure). The first driving member 4 may drive the liquid supply assembly 1, the first roller 2, and the second roller 3 to reciprocate between the initial position and the preset position, thereby completing the transfer work.

Alternatively, the first roller 2 and/or the second roller 3 may be equipped with a motor for driving rotation. For example, the first roller 2 may be provided with a motor for driving the first roller 2 to rotate. Alternatively, the second roller 3 may be provided with a motor for driving the second roller 3 to rotate. Of course, the second roller 3 may not be provided with a motor, and the second roller 3 may rotate relatively after contacting the member to be printed 200 during the driving movement of the first driving member 4. Or the first roller 2 is not provided with a motor, and the rotation of the first roller 2 is driven by the second roller 3.

According to the utility model, the first driving piece 4 is arranged to drive the liquid supply assembly 1, the first roller 2 and the second roller 3 to move between the initial position and the preset position, so that the first roller 2 and the second roller 3 can synchronously move, the first roller 2 is used for homogenizing liquid and transferring PI liquid to the second roller, and therefore feeding in the coating process can be realized, the process of reciprocating feeding in the coating process can be reduced, and the coating efficiency can be improved; in addition, the liquid supply assembly 1, the first roller 2 and the second roller 3 are connected in series to form a whole, so that the integration degree is higher; meanwhile, the movable position can be regulated and controlled through the first driving piece 4, the area to be maintained is more controllable, and the maintenance safety is better.

In one embodiment, referring to fig. 1 to 3, the diameter of the first roller 2 is smaller than the diameter of the second roller 3. Specifically, the first roller 2 and the second roller 3 are both cylindrical, so that the diameter of the first roller 2 may be set to D1, and the diameter of the second roller 3 may be set to D2. Also, the length H1 of the first roller 2 may be equal to the length H2 of the second roller 3. The first roller 2 and the second roller 3 are not limited in particular, and may be fixed according to a specific application scenario.

Alternatively, D1 may range from 200mm to 500mm. H1 may range from 1000mm to 3000mm. Preferably, D1 is 400mm and H1 is 2300mm.

Alternatively, D2 may range from 800mm to 1200mm. The H2 may range from 1000mm to 3000mm. Preferably, D2 is 1000mm and H2 is 2300mm.

It will be appreciated that the diameter D2 of the second roller 3 in the above description should be the diameter of the roller body 3B in the above embodiment, and that the diameter of the second roller 3 may be slightly larger after the transfer plate 3A is added.

Alternatively, the cylinder body of the second roller 3 may be made of SUS 304 alloy. The advantages are that the alloy has the characteristics of wear resistance, NMP resistance and PI liquid corrosion resistance.

The first roller 2 is smaller than the second roller 3, so that the first roller 2 is lighter, the rotation runout generated by overlarge weight in the driving process is reduced, and the vibration generated in the synchronous movement process with the second roller 3 is reduced, so that the uneven display brightness phenomenon (Mura phenomenon) of the display screen is reduced. Meanwhile, compared with other identical mechanisms, the first roller 2 meeting the range has the advantages that the volume is reduced by 60%, the weight is reduced by 60% in the same proportion, the movable feasibility is realized, and the equipment is lighter; moreover, compared with other identical mechanisms, the volume is reduced by 60%, the number of the surface grooves 2A is smaller, and the cost of a single piece is reduced by 60%.

In one embodiment, referring to fig. 1 to 3, the transfer apparatus 100 further includes a support frame 6, a second driving member 7, and a third driving member 8. The first roller 2 and the second roller 3 are both arranged on the support frame 6, and the support frame 6 is driven by the first driving piece 4 to move; the second driving piece 7 is arranged on the supporting frame 6 and is in transmission connection with the first roller 2 so as to drive the first roller 2 to rotate; the third driving piece 8 is arranged on the supporting frame 6 and is in transmission connection with the second roller 3 so as to drive the second roller 3 to rotate.

Alternatively, the support frame 6 may also be a portal frame for carrying the first driving member 4, the first roller 2, the second roller 3, the second driving member 7 and the third driving member 8. The first driving member 4 can drive the support frame 6 to reciprocate on the table 5.

Optionally, the transfer apparatus 100 further includes a guide rail 9, and the guide rail 9 is engaged with the support frame 6 so that the support frame 6 can move on a preset path.

Optionally, the second driving member 7 and the third driving member 8 are variable frequency motors. The second driving piece 7 drives the first roller 2 to rotate, and the third driving piece 8 drives the second roller 3 to rotate.

In one embodiment, referring to fig. 1 to 3, the transfer apparatus 100 further includes a recovery member 10, where the recovery member 10 is mounted on the supporting frame 6, and the recovery member 10 is used for recovering PI liquid overflowed from the first roller 2. Specifically, the recovery member 10 may be a rectangular box without a cover, and is located below the first roller 2 with respect to the table 5.

In one embodiment, referring to fig. 1 to 3, a liquid supply assembly 1 includes a liquid supply member 1A and a guide member 1B, wherein the liquid supply member 1A is configured to provide PI liquid; the guide piece 1B is rotatably connected with the first roller 2 and receives PI liquid provided by the liquid supply piece 1A, and when the first roller 2 rotates, the guide piece 1B is kept stationary.

Alternatively, the liquid supply member 1A may be a needle.

Alternatively, the diameter D3 of the liquid outlet of the liquid supply member 1A is 1mm to 5mm, and the length H3 may be 100mm to 200mm. The material is 304 stainless steel.

Preferably, D3 is 3mm and H3 is 150mm.

Optionally, the tip needle opening (liquid supply member 1A) is 45 ° inclined. The tail end of the liquid supply part 1A is provided with threads and is connected to a PI liquid supply pipeline.

Alternatively, the guide 1B may be a rectangular parallelepiped plastic, wherein the width D4 of the guide 1B may be 200mm to 300mm, the length may be 1000mm to 3000mm, and the thickness H4 may be 1mm to 5mm. The guide 1B may have wear-resistant and corrosion-resistant properties.

Preferably, D4 is 250mm, length is 2300mm, and H4 is 2mm.

In one embodiment, referring to fig. 1 to 3, the transfer apparatus 100 includes a working surface 5A, the working surface 5A is used for supporting a to-be-printed member, the guide 1B includes a guide surface 1B1, the guide surface 1B1 receives PI liquid, and an included angle is formed between the guide surface 1B1 and the working surface 5A.

Specifically, the table 5 includes the above-described working surface 5A. Preferably, the working surface 5A is the ground or the horizontal surface. The guide surface 1B1 is a surface of the guide 1B facing the liquid supply member 1A. When the first roller 2 rotates, the guide 1B scrapes PI liquid onto the first roller 2.

Alternatively, the angle α between the guide surface 1B1 and the working surface 5A may be 0 ° to 90 °.

Preferably, the angle between the guide surface 1B1 and the working surface 5A may be 45 °. Thereby forming a 45 deg. cutting edge which can be pressed against the outer circumferential surface of the first roller 2. Thus, a V-shaped accommodating groove is formed with the outer circumferential surface of the first roller 2, and PI liquid is accommodated in the accommodating groove.

In one embodiment, referring to fig. 1 to 3, a groove 2A is formed on the outer surface of the first roller 2, and a guide 1B extends into the groove 2A and guides PI liquid into the groove 2A. Specifically, the groove 2A is mainly used for accommodating PI liquid, so the shape of the groove 2A may not be particularly limited.

Alternatively, the guide 1B may extend at least partially into the recess 2A, and be designed with an included angle that is complementary to the guide 1B, whereby the guide 1B may guide PI liquid into the recess 2A.

In one embodiment, the number of grooves 2A is plural, and the volume of any one groove 2A is 60PL to 90PL.

In one embodiment, referring to fig. 1 to 3, the working table 5 includes a working surface 5A, the working surface 5A is used for supporting a workpiece to be printed, the first roller 2 and the second roller 3 move on the working surface 5A, the working surface 5A is further provided with a vacuum hole 11, and the air pressure in the vacuum hole 11 is less than normal pressure.

Alternatively, a vacuum pipe 12 may be connected below the table 5, the vacuum hole 11 communicates with the vacuum pipe 12, and the gas in the vacuum hole 11 is discharged through the vacuum pipe 12, thereby forming a negative pressure. The glass substrate is thereby sucked and fixed on the table 5 without being deviated by the moving second roller 3.

Alternatively, the vacuum line 12 may be provided with a solenoid valve control switch. The negative pressure fixing device is mainly used for fixing the glass substrate by providing negative pressure during coating, and relieving pressure after transfer printing is completed so that the glass substrate can move.

In one embodiment, the workbench 5 further includes a positioning portion 13, where the positioning portion 13 is located on the working surface 5A, and the positioning portion 13 is used for determining that the to-be-printed piece is placed at a preset position.

Optionally, a plurality of positioning nails (positioning parts 13) may be disposed on the working surface 5A, and the positioning nails are mainly used for mechanical alignment after the glass substrate enters the working table 5, so that the position to be coated of the glass substrate can correspond to the second roller 3.

Preferably, there are 8 positioning portions 13 in total.

In one embodiment, the present utility model provides a workflow of the transfer apparatus 100. Comprising the following steps:

the liquid supply piece 1A drops a proper amount of PI into the guide piece 1B, the guide piece 1B is connected with the first roller 2, and the guide piece 1B and the working surface 5A form an included angle, so that the guide piece 1B and the first roller 2 form a containing groove, and the PI is contained in the containing groove.

The guide 1B is pressed with a proper pressure to extend into the groove 2A on the first roller 2, and at the same time the first roller 2 rotates clockwise (or counterclockwise), the guide 1B scrapes the PI liquid in the accommodating groove into the groove 2A on the outer surface of the first roller 2.

After the first roller 2 is driven by the second driving member 7 to rotate for one circle, the grooves 2A on the outer surface of the first roller 2 are filled with PI liquid.

The first roller 2 moves towards the second roller 3, and the second roller 3 is pressed with a certain pressure; transfer plate 3A at outer periphery of second cylinder 3

PI liquid in the grooves 2A on the surface of the first roller 2 forms droplets on the outer surface of the transfer plate 3A.

After the second roller 3 and the first roller 2 synchronously rotate for one circle, the transfer printing plate 3A completes transfer printing and has a coating function.

The first driving piece 4 drives the supporting frame 6 to drive the second roller 3, the first roller 2, the liquid supply assembly 1 and the recovery piece 10 to do linear motion.

After the first template on the transfer plate 3A is aligned with the second template on the piece to be printed 200, the linear speed of the rotation of the second roller 3 is matched with the linear motion speed driven by the first driving piece 4, so that the second roller 3 finishes coating on the surface of the piece to be printed 200.

When the support moves downstream of the workpiece 200 to be printed, the solenoid valve of the vacuum pipe is opened to release the vacuum suction of the work bar. The work table 5 may jack up the work 200 to be printed and then take out the work that has been coated by the industrial robot.

The industrial robot feeds the uncoated part 200 to be printed and then circulates the above steps, resulting in a cyclical production.

Aiming at the defects of an RC type PI coating machine, the device creatively adopts a reduced version coating roller (a first roller 2) and a transfer roller (a second roller 3) to be synchronously fixed on a walking portal frame (a supporting frame 6), and then utilizes a linear motor (a first driving piece 4) to finish reciprocating coating, so that the theoretical takt time can reach 22sec/sheet, the speed is increased by 47.62%, and the manufacturing cost is reduced to a certain extent. Meanwhile, the coating of the same glass substrate can be increased, the function of fractional coating is realized, the APR plate line number and the hole pitch are matched and optimized, better diffusivity is achieved, and the alignment film with higher quality is obtained. The reduced version coating roller has light weight and small vibration, and reduces the vibration Mura incidence rate.

In the description of the embodiments of the present utility model, it should be noted that, the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like are merely for convenience of description and simplicity of description, and are not to be construed as limiting the utility model, as the means or elements referred to must have a specific orientation, be constructed and operated in a specific orientation.

The above disclosure is only a preferred embodiment of the present utility model, and it should be understood that the scope of the utility model is not limited thereto, but all or part of the procedures for implementing the above embodiments can be modified by one skilled in the art according to the scope of the appended claims.

Claims (10)

1. A transfer apparatus for transferring a pattern to a member to be printed fixed at a predetermined position; the transfer apparatus includes:

the liquid supply assembly is used for providing PI liquid;

the first roller is rotationally connected with the liquid supply assembly, and is used for receiving PI liquid provided by the liquid supply assembly and uniformly distributing the PI liquid on the peripheral surface of the first roller;

the second roller is rotationally connected with the first roller, receives PI liquid on the first roller, and distributes the PI liquid on the outer peripheral surface of the second roller according to a preset pattern;

the first driving piece is connected with the first roller and the second roller and drives the liquid supply assembly, the first roller and the second roller to move between an initial position and a preset position at the same time.

2. The transfer apparatus of claim 1, wherein a diameter of the first roller is smaller than a diameter of the second roller.

3. The transfer apparatus according to claim 1, characterized in that the transfer apparatus further comprises:

the support frame is connected with the first driving piece, the first roller and the second roller are both arranged on the support frame, and the first driving piece drives the support frame to move;

the second driving piece is arranged on the supporting frame and is in transmission connection with the first roller so as to drive the first roller to rotate;

and the third driving piece is arranged on the supporting frame and is in transmission connection with the second roller so as to drive the second roller to rotate.

4. The transfer apparatus of claim 3, further comprising a recovery member mounted on the support frame, the recovery member for recovering PI liquid overflowed from the first roller.

5. The transfer apparatus of claim 1, wherein the liquid supply assembly comprises:

the liquid supply piece is used for providing the PI liquid;

and the guide piece is rotationally connected with the first roller and used for receiving PI liquid provided by the liquid supply piece, and the guide piece is kept static when the first roller rotates.

6. The transfer device of claim 5, comprising a working surface for supporting a part to be printed, the guide comprising a guide surface that receives the PI liquid and has an included angle with the working surface.

7. The transfer apparatus of claim 5, wherein the first roller has a groove formed in an outer surface thereof, and the guide extends into the groove and guides the PI liquid into the groove.

8. The transfer apparatus according to claim 7, wherein the number of the grooves is plural, and a volume of any one of the grooves is 60PL to 90PL.

9. The transfer printing apparatus of claim 1, further comprising a table, the table comprising a working surface for supporting a part to be printed, the first roller and the second roller moving on the working surface, the working surface further having a vacuum hole, the air pressure within the vacuum hole being less than normal pressure.

10. The transfer apparatus of claim 9, wherein the table further comprises a positioning portion on the work surface for determining that the part to be printed is placed at a preset position.