JP6519547B2 - Method of manufacturing image reading apparatus - Google Patents

Description

  The present invention relates to a method of manufacturing an image reader, and more particularly to a method of manufacturing a contact glass of a sheet-through type image reader.

  In a sheet-through type image reading apparatus, a document to be read is conveyed toward the main surface of the contact glass, and the document is read by an image sensor fixed to the surface opposite to the main surface of the contact glass. , Get an image showing the original. Contact glass is generally manufactured by a float method in which molten glass is flowed and formed on molten metal contained in a bath. By producing the contact glass by the float method, the thickness of the glass can be made uniform.

JP, 2014-53845, A

  Every time the document is read, the document is conveyed toward the main surface of the contact glass, and the document contacts the main surface of the contact glass. Therefore, the main surface of the contact glass is required to have high durability against friction with the document. . In order to increase the durability against friction with the original, generally, a liquid fluorine coating agent is applied to the main surface of the contact glass, and the main surface of the contact glass is naturally dried to form fluorine on the main surface of the contact glass It is practiced to form a coating film.

  Here, in order to further enhance the durability of the main surface of the contact glass against friction with the original, plasma treatment may be performed on the main surface of the contact glass before fluorine coating, or baking of the contact glass after fluorine coating Conceivable.

  However, depending on which of the two main surfaces of the contact glass manufactured by the float method is subjected to plasma treatment or fluorine coating, the performance such as the durability of the contact glass may change. When contact glass is manufactured by the float method, the two main surfaces of the contact glass have a tin surface in contact with tin and a non-tin surface not in contact with tin, but thin tin adheres to the tin surface. There is. When plasma treatment or fluorine coating is performed on the tin surface, tin deposited on the contact glass may adversely affect the durability of the contact glass.

  Therefore, when performing plasma processing or fluorine coating, it is specified which of the two main surfaces of the contact glass is a non-tin surface, and plasma processing or fluorine coating is applied to the specified non-tin surface. By doing this, the performance of the contact glass can be enhanced, such as durability.

  The present invention has been made in view of the above circumstances, and when performing plasma treatment or fluorine coating on contact glass, any of the two main surfaces of the contact glass is a non-tin surface. The purpose is to make it possible to easily identify the non-tin side with plasma treatment and fluorine coating treatment.

  In the method of manufacturing an image reading apparatus according to one aspect of the present invention, an image sensor which conveys a document to be read toward a contact glass and fixes the conveyed document at a predetermined position of the contact glass A manufacturing method of manufacturing a sheet-through type image reading apparatus for reading by a first method, wherein the contact glass is manufactured by a float method in which molten glass is flowed and formed on molten metal accommodated in a bath; A first main surface of the contact glass in contact with the molten metal in the first step after the first step and a surface on the opposite side to the first main surface, and the molten metal in the first step Forming a mark indicating the second principal surface of the contact glass not in contact with the contact glass, and after the second step, A third step of applying plasma treatment to the second main surface indicated by the mark formed on the tact glass, and a second main surface indicated by the mark formed on the contact glass after the third step A fourth step of applying a fluorine coating treatment, a fifth step of firing the contact glass after the fourth step, and a second main surface indicated by the mark formed on the contact glass after the fifth step Is located on the side of the housing of the image reading apparatus in contact with the conveyed document, and the first main surface indicated by the mark is located on the side where the image sensor is installed in the housing And a sixth step of fixing the contact glass in the housing.

  According to the present invention, when performing plasma processing or fluorine coating on contact glass, it is possible to easily identify which of the two main surfaces of the contact glass is the non-tin surface. Thus, it becomes possible to reliably perform plasma treatment and fluorine coating treatment on the non-tin side.

FIG. 1 is a perspective view showing an image forming apparatus provided with an image reading apparatus to be manufactured by a manufacturing method according to an embodiment of the present invention. FIG. 2 is a cross-sectional view showing an image reading apparatus to be manufactured by a manufacturing method according to an embodiment of the present invention. It is a perspective view showing the image reading device which is the manufacturing object by the manufacturing method concerning one embodiment of the present invention. FIG. 3 is an enlarged view showing a configuration around a conveyance guide member of the image reading apparatus shown in FIG. 2; It is a figure showing the device which manufactures the 1st contact glass of an image reading device. It is the flowchart which showed the process of manufacturing the 1st contact glass of the image reading device. (A)-(C) are figures which show the 1st contact glass after a marking process. (A) is a flowchart which shows the process of fixing the 1st contact glass and the 2nd contact glass in the case of a reading part, (B) is the details of a part of process shown to (A). It is a flowchart which shows a process. It is a top view which shows the housing | casing of the reading part of the image reader which is the manufacturing object by the manufacturing method concerning one Embodiment of invention. It is a figure which shows the experimental result regarding the manufacturing method concerning one Embodiment of invention. It is a figure which shows the experimental result regarding the manufacturing method concerning one Embodiment of invention.

  Hereinafter, a method of manufacturing an image reading apparatus according to an embodiment of the present invention will be described with reference to the drawings.

  First, an image reading apparatus to be manufactured by a method of manufacturing an image reading apparatus according to an embodiment of the present invention will be described. As shown in FIG. 1, the image forming apparatus 1 is roughly configured of an apparatus main body 80 and an image reading apparatus 10 disposed above the apparatus main body 80.

  An image forming unit (not shown) and the like are accommodated in a housing 81 constituting an outer shell of the apparatus main body 80. The image forming unit forms a toner image of the document read by the image reading device 10 by the steps of charging, exposure, and development, and discharges the recording sheet on which the toner image is transferred to the discharge tray 82.

  The image reading apparatus 10 includes a reading unit 30 and a document conveyance unit 20 disposed above the reading unit 30. FIG. 2 is a cross-sectional view showing the image reading apparatus 10, and FIG. 3 is a perspective view showing the image reading apparatus 10. As shown in FIG. As shown in these drawings, the document conveyance unit 20 of the image reading apparatus 10 includes a document placement table 21, a document discharge tray 22, a pickup roller 25, a conveyance roller 26, a discharge roller 27, and the like.

  The document transport unit 20 feeds the document sheet by sheet from the document bundle placed on the document placement table 21 by the pickup roller 25, and the document fed by the transport roller 26 is the main of the first contact glass 32 described later. Transport toward the surface (first surface). The document conveyed to the first contact glass 32 is read by a scanner 34 described later at a predetermined document reading position, and then discharged to the document discharge tray 22 by the discharge roller 27.

  The reading unit 30 includes a box-shaped case 31. An opening is provided on the upper surface 31A of the housing 31 (the surface facing the document conveying unit 20 when the document conveying unit 20 is closed), and the first contact glass 32 and the second contact glass are provided in the opening. 33 is attached. The first contact glass 32 is a contact glass for reading the document conveyance, and the document is conveyed from the document conveyance unit 20. The second contact glass 33 is a contact glass for document fixing and reading, on which the document is placed. The document transport unit 20 provided above the second contact glass 33 is provided so as to be freely opened and closed with respect to the main surfaces of the first contact glass 32 and the second contact glass 33. Thus, the document placed on the second contact glass 33 is fixed.

  A scanner 34 movable in the sub-scanning direction is provided on the lower surface (second surface) side opposite to the main surfaces of the first contact glass 32 and the second contact glass 33. The scanner 34 incorporates a CIS (Contact Image Sensor) type image sensor stretched in the main scanning direction.

  In the document fixed reading, the scanner 34 reciprocates in the sub scanning direction to read the document placed on the second contact glass 33. On the other hand, in the document conveyance reading, the scanner 34 is fixed at a predetermined position (image reading position) on the back surface of the first contact glass 32 and directed to the main surface of the first contact glass 32 by the document conveyance unit 20. Scan the originals transported. Image data obtained by reading the document is stored in an image memory or an HDD incorporated in the image reading apparatus 10.

  The reading unit 30 further includes a conveyance guide member 35 on the main surface of the first contact glass 32. FIG. 4 is an enlarged cross-sectional view showing the configuration around the transport guide member 35. As shown in FIG. As shown in FIGS. 2 to 4, the conveyance guide member 35 is a long sheet extending in the main operation direction, and the adhesive is provided at a predetermined position on the main surface of the first contact glass 32. It is adhered by 36. The predetermined position is a position near the position (image reading position) of the scanner 34 at the time of document conveyance reading, and is a position outside the reading range by the scanner 34 at the document conveyance reading. The leading end of the transport guide member 35 provided at the predetermined position enters a transport path of the document transported by the transport roller 26. As a result, as shown in FIG. 4, the leading end of the conveyance guide member 35 contacts the document discharged from the opening 26A on the upstream side in the document conveyance direction with respect to the reading range of the scanner 34. The document discharged from the opening 26 </ b> A travels to the image reading position of the first contact glass 32 while in contact with the leading end of the conveyance guide member 35. When the document comes in contact with the leading end of the conveyance guide member 35, foreign matter such as dust attached to the document is removed by the leading end of the conveyance guide member 35. Thus, in addition to the role of guiding the document to the image reading position of the first contact glass 32, the transport guide member 35 also plays a role of removing foreign matter attached to the document.

  Subsequently, a method of manufacturing the image reading apparatus 10 described above will be described. The configuration other than the reading unit 30 of the image reading apparatus 10, for example, the method of manufacturing the document conveyance unit 20 is the same as a general manufacturing method, and thus the description thereof will be omitted.

  First, a method of manufacturing the first contact glass 32 will be described. FIG. 5 is a view showing an apparatus for manufacturing the first contact glass 32. As shown in FIG. FIG. 6 is a flowchart showing steps of manufacturing the first contact glass 32. As shown in FIG.

  First, glass raw materials such as silica sand, sodium carbonate (soda ash), calcium carbonate, dolomite are put into the dissolution tank (step S1), and the glass raw materials are melted by heating to 1600 ° C. or more to form molten glass. (Step S2). Then, the generated molten glass is poured into a float bath filled with a molten metal (tin in this embodiment) (step S3). The molten glass poured into the float bath floats in a band on the tin filled in the melting tank. By floating the molten glass on the molten tin, it is possible to produce a glass having a uniform thickness and a smooth surface. In addition, the temperature of the molten glass may be lowered to 1100 ° C. to 1300 ° C., and a process of extracting the internal air may be added between the above-described melting process (step S2) and the float process (step S3).

  After the float process of step S3, the temperature of the glass is gradually lowered in the annealing line (step S4). By gradually lowering the temperature of the glass, it is possible to prevent internal distortion.

  After the annealing step of step S4, the glass is cut into the size of the first contact glass 32 (step S5). Then, after the glass is cut, the first surface (tin surface) of the first contact glass 32 in contact with the tin melted in the float process in step S3 and the first surface are the surfaces on the opposite side, and the float process A mark indicating the second surface (non-tin surface) of the first contact glass 32 not in contact with the melted tin and the second contact glass 32 is formed on the first contact glass 32 (step S6).

  FIGS. 7A to 7C are views showing the first contact glass 32 after the process of step S6. 7A, the main surface 33B facing upward in the drawing is the second surface (non-tin surface) not in contact with tin, and the main surface 33A facing downward in the drawing is in contact with tin the first surface (tin Face). In the present embodiment, when viewed from the first surface side (the Z-axis direction in the drawing), a notch 331 in which any one of four corners of the first contact glass 32 is cut at an angle of about 45 degrees. Is formed on the first contact glass 32 as the above-mentioned mark.

  Here, if the main surface 33A and the main surface 33B of the first contact glass 32 have a square rectangular shape, any one of the four corners of the first contact glass 32 as described above is cut out. Of the two main surfaces of the first contact glass 32, it is not possible to identify the surface which is a tin surface or a non-tin surface by the cutaway portion 331 alone. In the present embodiment, since the main surface 33A and the main surface 33B of the first contact glass 32 have a rectangular shape, storing the position where the cutout portion 331 is formed allows the first visual inspection to be performed thereafter. Of the two main surfaces of the contact glass 32, the surface which is a tin surface or a non-tin surface can be identified. Although the details will be described later, a step of adhering a sheet-like member to be performed later by forming the above-described mark on the first contact glass 32, a plasma treatment step, a fluorine coating treatment step, and a first step In the step of fixing the contact glass 32 of the first embodiment to the housing 31 of the reading unit 30, etc., among the two main surfaces of the first contact glass 32, a main surface which can be more effectively treated is specified. Since the specified main surface can be treated, the durability and the like of the first contact glass 32 can be improved.

  In addition, when manufacturing the 2nd contact glass 33, it is not necessary to perform the marking process of step S6 among the processes of said step S1-step S6.

  Subsequently, a method of fixing the first contact glass 32 and the second contact glass 33 in the housing 31 of the reading unit 30 will be described. FIG. 8A is a flow chart showing a process of fixing the first contact glass 32 and the second contact glass 33 in the housing 31 of the reading unit 30. FIG. 8B is a flow chart showing in detail the process of step S12 shown in FIG. 8A. As shown in these figures, first, the first contact glass 32 and the second contact glass 33 manufactured by the method described above are prepared (S11). Then, the first contact glass 32 is processed (step S12), and thereafter, the first contact glass 32 and the second contact glass 33 after the processing are processed in the housing 31 of the reading unit 30. (Step S13). In addition, although the process and the wiring process of mounting the scanner 34 and other members in the housing 31 of the reading unit 30 are required to complete the manufacture of the reading unit 30, general manufacturing is performed for these steps. Description is omitted because it is the same as the method.

  The details of the processing step for the first contact glass 32 in step S12 will be described. In the step, first, a sheet-like member is bonded as a conveyance guide member 35 at a predetermined position on the main surface of the first contact glass 32 (step S21). In step S21, a heat-resistant and insulating member is used as the sheet-like member. Here, the heat resistance specifically refers to the ability to withstand heat of 150 degrees or more. Such a member corresponds to, for example, a member based on polyvinyl chloride or polyethylene.

  Further, in the process of step S21, the main surface to which the sheet-like member is bonded is a non-tin surface among the two main surfaces of the first contact glass 32. In the process of step S21, which of the two main surfaces of the first contact glass 32 is a non-tin surface is specified from the position of the notch 331 formed in the process of step S6. A sheet-like member is adhered to the identified non-tin surface.

  Bonding the sheet-like member not to the tin surface but to the non-tin surface is the surface to which the sheet-like member is bonded in the process described later (steps S22 and S23), and to the non-tin surface This is because it is necessary to apply a treatment step and a fluorine coating treatment step.

  Here, the transport guide member 35 is a member for guiding the document to the image reading position of the first contact glass 32 and for removing foreign matter attached to the document, but only for these functions. As long as the conveyance guide member 35 is a sheet-like member, it is not necessary to employ a member having heat resistance and insulation as described above. In the present embodiment, the sheet-like member having heat resistance and insulation is adopted as the conveyance guide member 35 for the following reason.

  In general, when bonding another member such as the transport guide member 35 to the first contact glass 32, the process is performed after the processing on the first contact glass 32 is performed. However, in the present embodiment, in order to improve the durability and the like of the first contact glass 32, plasma treatment, fluorine coating treatment, and firing treatment are performed on the first contact glass 32, and after the treatment, the first treatment is performed. It is difficult to bond another member to the contact glass 32 of Therefore, in the present embodiment, the transport guide member 35 is adhered to the first contact glass 32 before the plasma processing, the fluorine coating processing, and the baking processing are performed.

  However, when the transport guide member 35 is adhered to the first contact glass 32 before performing the plasma processing, the fluorine coating processing, and the firing processing, the transport guide in the process of the plasma processing, the fluorine coating processing, and the firing processing. The member 35 is deformed or peeled off.

  In addition, it is conceivable to cover the area to which the transport guide member 35 is adhered using a masking tape and then to perform plasma processing or fluorine coating processing on the main surface of the first contact glass 32. As a result, the main surface of the first contact glass 32 can be subjected to plasma treatment or fluorine coating except for a range to which another member such as the conveyance guide member 35 is adhered, and the conveyance guide member 35 can be It can be adhered to the main surface of the first contact glass 32. However, in this case, the masking tape is deformed or peeled off in the steps of plasma treatment, fluorine coating treatment, and firing treatment. In addition, since the number of work processes is increased by the masking process, the manufacturing work efficiency of the image reading apparatus 10 is reduced.

  In this respect, according to the manufacturing method according to the embodiment of the present invention, a sheet-like member having heat resistance and insulation is adopted as the conveyance guide member 35, and before the plasma treatment step or the fluorine coating treatment step. Since the sheet-like member is adhered to the first contact glass 32 as the conveyance guide member 35, the conveyance guide member 35 is adhered to the main surface of the first contact glass 32 in a small number of operation steps. The image reader 10 can be manufactured. Further, although the details will be described later, since the first contact glass 32 is subjected to plasma treatment, fluorine coating treatment, and baking treatment, the durability against the friction between the first contact glass 32 and the document is generally Higher than the image reader.

  After the process of step S21, the non-tin surface of the first contact glass 32 is subjected to plasma treatment (step S22). At this time, which of the two main surfaces of the first contact glass 32 is a non-tin surface is specified from the position of the notch 331 formed in the step S6. Further, the surface on the side to which the conveyance guide member 35 is adhered in the process of step S21 may be specified as a non-tin surface.

  Of the two main surfaces of the first contact glass 32, thin tin adheres to the tin surface. Therefore, as described above, by specifying the tin surface and the non-tin surface and performing the plasma processing on the non-tin surface side, the surface treatment effect by the plasma processing can be enhanced.

  In the plasma processing, the first contact glass 32 is placed in the chamber, a plasma is generated in the chamber, and the generated plasma is irradiated to the non-tin surface of the first contact glass 32. This plasma irradiation gives energy higher than the bond energy of the atoms constituting the foreign matter such as C—C bond, C—H bond, and C—O bond, so the foreign matter attached to the non-tin surface of the first contact glass 32 is removed. In addition, since the molecules such as OH groups ionized by the plasma irradiation are modified on the surface of the first contact glass 32, the wettability of water is improved.

  Since the transport guide member 35 bonded to the non-tin surface of the first contact glass 32 is made of an insulating member, it does not burn even when a voltage of several hundred volts is applied by plasma processing. .

  After the step S22, the non-tin surface of the first contact glass 32 is subjected to a fluorine coating process (step S23). Specifically, a liquid fluorine coating agent is sprayed toward the non-tin surface of the first contact glass 32 by spraying to solidify the sprayed fluorine coating agent on the non-tin surface of the first contact glass 32. Let Thereby, a fluorine coating film is formed on the non-tin surface of the first contact glass 32. In the process of step S22, since the non-tin planar foreign matter of the first contact glass 32 is removed and the wettability of water is improved, a fine fluorine coating film can be formed.

  Here, in general, a fluorine coating film is formed on the main surface of the contact glass by applying a liquid fluorine coating agent and naturally drying the main surface of the contact glass. As compared to this conventional process, a more dense fluorine coating film can be formed by spraying the liquid fluorine coating agent as described above.

  Further, in the process of step S23, which of the two main surfaces of the first contact glass 32 is a non-tin surface is specified from the position of the notch 331 formed in the process of step S6. Further, the surface on the side to which the conveyance guide member 35 is adhered in the process of step S21 may be specified as a non-tin surface. Thus, by specifying the tin surface and the non-tin surface and performing the fluorine coating treatment on the non-tin surface side, the surface treatment effect by the fluorine coating treatment can be enhanced.

  After the process of step S23, the side surfaces (the surfaces 33C, 33D, 33E, and 33F shown in FIG. 7B) of the first contact glass 32 are polished (step S24). In the case where another member is adhered to the side surface of the first contact glass 32 or an adhesive may be applied in the assembly process of step S26 described later, the first contact can be performed by performing the above process. The fluorine coating on the side of the glass 32 is removed. In addition, it is not necessary to grind | polish all four side surfaces of the 1st contact glass 32 necessarily, and it is not necessary to grind | polish the side which does not adhere | attach another member. In addition, the polishing process of step S24 may be performed after the firing process of step S25 described later.

  After the process of step S25, the first contact glass 32 is fired in a constant temperature bath. Specifically, baking is performed for 30 minutes at a temperature of 150 degrees (step S25). The transport guide member 35 bonded to the non-tin surface of the first contact glass 32 is made of a heat-resistant member, and therefore is not damaged or burned in the firing step of step S25.

  The above is the details of the process of processing the first contact glass 32 in step S12. After the step S12, the first contact glass 32 and the second contact glass 33 are mounted in the housing 31 of the reading unit 30 (step S13). At this time, the non-tin surface indicated by the mark formed on the first contact glass 32 is located on the side to be in contact with the conveyed document, and the tin surface is on the side where the image sensor 34 in the housing 31 is installed. The first contact glass 32 is fixed in the housing 31 so as to be positioned.

  FIG. 9 is a top view showing the case 31 of the reading unit 30. As shown in FIG. As shown in the figure, the upper surface 31A of the housing 31 is formed with an insertion hole 31B into which the first contact glass 32 is inserted and an insertion hole 31C into which the second contact glass 33 is inserted. The insertion hole 31B has a shape corresponding to the notch 331 formed in the first contact glass 32, and the first contact glass 32 is inserted into the insertion hole 31B to perform plasma processing and fluorine coating. The non-tin side subjected to the processing is positioned on the side to be in contact with the conveyed document, and the tin side is positioned on the side where the scanner 34 in the housing 31 is installed. It is fixed in the body 31.

  <Experiment>

  The applicant conducted the following experiment based on earnest research, and came to think of the above-mentioned technique from the experimental result.

<Experiment 1>
(1) Three kinds of fluorine coating agents of A, B and C having different friction coefficients, (2) presence or absence of plasma treatment, and (3) changing the three conditions of fluorine coating method (spray injection or application) The surface processing of the first contact glass 32 was performed. The results are shown in FIG. In FIG. 10, the durability means that when the first contact glass 32 is abraded under the conditions of a load of 1 kg, a contact area of 1 cm × 1 cm, and a speed of 60 cycles / min using steel wool, the water contact angle is It shows the number of times it took to reach 100 degrees or less. Further, the 1000-time water contact angle indicates a water contact angle when worn 1000 times using steel wool. Further, the dynamic friction coefficient indicates a value measured using paraffin paper under a load of 200 gf and a speed of 200 mm / min.

  Comparing the results of sample numbers 3, 4 and 5, 6 shown in FIG. 10, the durability of the first contact glass 32 is greatly improved by performing the plasma treatment before the fluorine coating treatment. I understand. Moreover, when the result of sample number 1, 2 and 9 is compared, when a fluorine coating is carried out by spray injection, compared with the case where a fluorine coating is carried out by application, the dynamic friction coefficient is significantly lower. In addition, when the fluorine coating is performed by the spray injection, the water contact angle is higher than the case where the fluorine coating is performed by the application. Therefore, when the document is conveyed to the first contact glass 32, unnecessary friction is not applied to the document from the first contact glass 32. Moreover, sample numbers 7 and 8 using the fluorine coating agent with the lowest coefficient of friction give the best results for each of the indicators of durability, coefficient of dynamic friction, and water contact angle.

  From the above consideration, it is understood that it is optimal to perform plasma treatment on the first contact glass 32 and then to perform fluorine coating by spray coating.

<Experiment 2>
After each member of polycarbonate, polyethylene terephthalate, crepe paper, polyvinyl chloride, and polyethylene was adhered to the first contact glass 32, the steps of plasma treatment, fluorine coating treatment, and baking treatment were performed. The results are shown in FIG.

  With respect to polycarbonate and polyethylene terephthalate, the heat of the firing step caused expansion or contraction, and displacement occurred. In addition, for crepe paper, burning and breakage were observed due to plasma treatment. This is considered to be because crepe paper has a heat resistance of 160 degrees but is not insulating. As for polyvinyl chloride and polyethylene, no burn or breakage was observed even when each step of plasma treatment, fluorine coating treatment, and firing treatment was performed. It is considered that this is because polyvinyl chloride has heat resistance of 150 degrees and is insulating, and polyethylene has heat resistance of 200 degrees and is insulating.

  From the above consideration, a sheet-like member having heat resistance and insulation is adopted as the conveyance guide member 35, and the sheet-like member is used as a first contact glass before the plasma treatment step and the fluorine coating treatment step. By carrying out the step of bonding the transfer guide member 35 as the transfer guide member 35, it is possible to manufacture the image reading apparatus 10 in which the transfer guide member 35 is bonded to the main surface of the first contact glass 32 in a small number of operation steps. I understand.

<Modification>
The present invention is not limited to the configuration of the embodiment described above, and various modifications are possible.

  For example, in the polishing step of step S24 described above, not all the four side surfaces of the first contact glass 32 are polished, but the side surfaces in a predetermined position (for example, the surface shown in FIG. 7B). 33C) may be polished. By storing the position where the side surface of the first contact glass 32 is polished together with the position where the notch portion 331 is formed, tin of the two main surfaces of the first contact glass 32 is visually checked thereafter. Surfaces that are faces or non-tin faces can be identified more reliably.

  Moreover, although said embodiment demonstrated the case where the notch part 331 was formed as a mark which shows a tin surface and a non-tin surface, this invention is not necessarily limited to this case. For example, a cut may be made at the end on the tin surface side as the above mark.

DESCRIPTION OF SYMBOLS 1 image forming apparatus 10 image reading apparatus 20 document conveyance unit 30 reading unit 31 housing 32 first contact glass 33 second contact glass 34 scanner 35 conveyance guide member 331 cutout portion

Claims (7)

A manufacturing method of manufacturing a sheet-through type image reading apparatus of conveying a document to be read toward a contact glass and reading the conveyed document by an image sensor fixed at a predetermined position of the contact glass. There,
A first step of manufacturing the contact glass by a float process in which molten glass is flowed and formed on molten metal contained in a bath;
After the first step, a first main surface of the contact glass in contact with the molten metal in the first step and a surface on the opposite side to the first main surface, and the molten metal in the first step Forming a mark indicating the second main surface of the contact glass not in contact with the contact glass;
After the second step, performing a plasma treatment on the second main surface indicated by the mark formed on the contact glass;
After the third step, a fourth step of applying a fluorine coating treatment to the second main surface indicated by the mark formed on the contact glass;
A fifth step of firing the contact glass after the fourth step;
After the fifth step, the second main surface indicated by the mark formed on the contact glass is located on the side in contact with the conveyed document in the housing of the image reading apparatus, and is indicated by the mark And a sixth step of fixing the contact glass in the housing such that the first main surface to be positioned is located on the side where the image sensor is installed in the housing. The contact glass is a rectangular parallelepiped in which the first main surface and the second main surface are rectangular rectangular shapes,
In the second step, a notch in which any one of four corners of the contact glass is notched as viewed from the first main surface side is formed as the mark on the contact glass,
In the third step, the fourth step, and the sixth step, the first main surface and the second main surface of the contact glass are specified based on the position where the notch portion is formed. The manufacturing method of the image reading apparatus as described in these. The housing is formed with a fitting hole having a shape corresponding to the shape of the contact glass in which the cutout portion is formed,
In the sixth step, by inserting the contact glass into the insertion hole, the second main surface is positioned on the side in contact with the conveyed document in a housing of the image reading apparatus, The method for manufacturing an image reading apparatus according to claim 2, wherein the contact glass is fixed in the housing with the main surface positioned on the side where the image sensor is installed in the housing.   4. The method according to claim 1, further comprising, after the fourth step, polishing the side surface of the contact glass in which the notch portion is not formed among the side surfaces in the longitudinal direction. Method of manufacturing an image reading apparatus The image reading device contacts the document at a predetermined position outside the reading range of the contact glass by the image sensor by contacting the document on the upstream side of the reading direction with respect to the document feeding direction. An image reading apparatus provided with a conveyance guide member for guiding to a reading range,
After the second step, before the third step, there is further included a step of bonding a sheet-like member having heat resistance and insulation as the transport guide member to the predetermined position of the contact glass. A method of manufacturing an image reading apparatus according to any one of claims 1 to 4.   The method according to claim 5, wherein the sheet-like member is a member based on polyvinyl chloride or polyethylene.   In the fourth step, the liquid fluorine coating agent is sprayed toward the main surface of the contact glass by spraying to solidify the sprayed fluorine coating agent on the main surface of the contact glass. The manufacturing method of the image reader of Claim 5 or 6 which forms a fluorine coating film on the main surface of glass.